Spring Cloud Alibaba学习笔记

引自B站楠哥：https://space.bilibili.com/434617924

一、创建父工程

创建父工程hello-spring-cloud-alibaba

Spring Cloud Alibaba 的环境在父工程中创建，微服务的各个组件作为子工程，继承父工程的环境。

Spring Boot ---》Spring Cloud ---》Spring Cloud Alibaba

引入依赖时注意提前查询一下spring cloud的版本依赖关系。

pom文件为，父工程打包时应打成pom，否则子工程构建时无法打包成功。

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.3.0.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.yqd</groupId>
    <artifactId>hello-spring-cloud-alibaba</artifactId>
    <version>1.0.0-SNAPSHOT</version>
    <name>hello-spring-cloud-alibaba</name>
    <description>Demo project for hello-spring-cloud-alibaba</description>
    <packaging>pom</packaging>

    <properties>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
    </dependencies>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>Hoxton.SR3</version>
            </dependency>
            <dependency>
                <groupId>com.alibaba.cloud</groupId>
                <artifactId>spring-cloud-alibaba-dependencies</artifactId>
                <version>2.2.1.RELEASE</version>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <excludes>
                        <exclude>
                            <groupId>org.projectlombok</groupId>
                            <artifactId>lombok</artifactId>
                        </exclude>
                    </excludes>
                </configuration>
            </plugin>
        </plugins>
    </build>

</project>

父工程中只需要引入所需要的依赖就可以了，不用其他的资源，可以删除src目录和resources目录。

二、服务的提供者

在父工程中添加spring boot模块module，工程名字为provider。

pom文件为

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>com.yqd</groupId>
        <artifactId>hello-spring-cloud-alibaba</artifactId>
        <version>1.0.0-SNAPSHOT</version>
    </parent>
    <groupId>com.yqd</groupId>
    <artifactId>provider</artifactId>
    <version>1.0.0-SNAPSHOT</version>
    <name>provider</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
            <version>2.2.1.RELEASE</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

在子工程中要引入spring-cloud-starter-alibaba-nacos-discovery依赖，这样才可以注册到nacos中。

配置文件application.yml为：

spring:
  cloud:
    nacos:
      discovery:
        server-addr: localhost:8848
  application:
    name: provider

server:
  port: 8081

做个接口供外部调用：

package com.yqd.controller;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class ProviderController {

    @Value("${server.port}")  //SPEL
    private String port;

    @GetMapping("/index")
    public String index(){
        return this.port;
    }
}

下载解压nacos1.2.1，解压之后打开bin目录下的startup.cmd，然后通过url访问nacos，http://localhost:8848/nacos/index.html，登录的用户名和密码都默认是nocos。可以通过nacos查看注册的实例。

三、服务的消费者

在父工程中添加spring boot模块module，工程名字为consumer。

pom文件为

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>com.yqd</groupId>
        <artifactId>hello-spring-cloud-alibaba</artifactId>
        <version>1.0.0-SNAPSHOT</version>
    </parent>
    <groupId>com.yqd</groupId>
    <artifactId>consumer</artifactId>
    <version>1.0.0-SNAPSHOT</version>
    <name>consumer</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
            <version>2.2.1.RELEASE</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

在子工程中要引入spring-cloud-starter-alibaba-nacos-discovery依赖，这样才可以注册到nacos中。但是消费者只需要到提供者中调用接口就可以了，因此可以不用在配置文件中配置nacos。

配置文件application.yml为：

server:
  port: 8180

远程过程调用使用RestTemplate

package com.yqd.config;

import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import org.springframework.web.client.RestTemplate;

@Configuration
public class ConsumerConfiguration {
    @Bean
    @LoadBalanced //使用Ribbon进行远程调用
    @Primary
    public RestTemplate restTemplate(){
        return new RestTemplate();
    }
		
    //必须使用自己配置的这个Bean，并且使用名称注入，否则报错java.lang.IllegalStateException: No instances available for ...
    @Bean
    public RestTemplate restTemplateCustom(){
        return new RestTemplate();
    }
}

创建接口来从provider的接口中获取数据

package com.yqd.controller;

import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.cloud.client.discovery.DiscoveryClient;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

import java.util.List;
import java.util.concurrent.ThreadLocalRandom;

@RestController
@Slf4j
public class ConsumerController {
    //自动装载，直接用
    @Autowired
    private DiscoveryClient discoveryClient;
    //没有自动装载，不能直接用，需要用配置类装载
    @Autowired(required = false) // 必须使用自己配置的这个Bean，并且使用名称注入，否则报错
    @Qualifier("restTemplateCustom") // 表示根据名称来找bean
    private RestTemplate restTemplateCustom;

    /**
     * 返回服务实例
     * @return
     */
    @GetMapping("/instances")
    public List<ServiceInstance> instances() {
        List<ServiceInstance> provider = this.discoveryClient.getInstances("provider");
        return provider;
    }

    @GetMapping("/index")
    public String index(){
        //调用provider服务的index方法
        //1、找到provider实例
        List<ServiceInstance> list = this.discoveryClient.getInstances("provider");
        int index = ThreadLocalRandom.current().nextInt(list.size());//返回一个随机数
        ServiceInstance serviceInstance = list.get(index); //获取其中一个实例
        String url = serviceInstance.getUri()+"/index";//URL=URI+请求路径
        //2、调用
        log.info("调用的端口是，{}", serviceInstance.getPort());
        return "调用了端口为："+serviceInstance.getPort()+"的服务，返回结果是："+this.restTemplateCutom.getForObject(url, String.class);
    }
}

四、使用Ribbon做负载均衡

配置类

@Configuration
public class ConsumerConfig {

    @Bean
    @LoadBalanced
    public RestTemplate restTemplate(){
        return new RestTemplate();
    }

}

@RestController
public class ConsumerController {

    @Autowired
    private RestTemplate restTemplate;

    @GetMapping("/index")
    public String index(){
        return "consumer远程调用provier："+this.restTemplate.getForObject("http://provider/index", String.class);
    }

}

application.yml中配置，随机调用机器

server:
  port: 8180
provider:
  ribbon:
    NFLoadBalancerRuleClassName: com.netflix.loadbalancer.RandomRule

Nacos 权重配置，在nacos中配置机器的权重，权重越高被访问的概率越大

package com.yqd.config;

import com.alibaba.cloud.nacos.NacosDiscoveryProperties;
import com.alibaba.cloud.nacos.ribbon.NacosServer;
import com.alibaba.nacos.api.exception.NacosException;
import com.alibaba.nacos.api.naming.NamingService;
import com.alibaba.nacos.api.naming.pojo.Instance;
import com.netflix.client.config.IClientConfig;
import com.netflix.loadbalancer.AbstractLoadBalancerRule;
import com.netflix.loadbalancer.BaseLoadBalancer;
import com.netflix.loadbalancer.ILoadBalancer;
import com.netflix.loadbalancer.Server;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;

@Slf4j
public class NacosWeightedRule extends AbstractLoadBalancerRule {

    @Autowired
    private NacosDiscoveryProperties nacosDiscoveryProperties;

    @Override
    public void initWithNiwsConfig(IClientConfig iClientConfig) {
        //读取配置文件
    }

    @Override
    public Server choose(Object o) {
        ILoadBalancer loadBalancer = this.getLoadBalancer();
        BaseLoadBalancer baseLoadBalancer = (BaseLoadBalancer) loadBalancer;
        //获取要请求的微服务名称
        String name = baseLoadBalancer.getName();
        //获取服务发现的相关API
        NamingService namingService = nacosDiscoveryProperties.namingServiceInstance();
        try {
            Instance instance = namingService.selectOneHealthyInstance(name);
            log.info("选择的实例是port={},instance={}",instance.getPort(),instance);
            return new NacosServer(instance);
        } catch (NacosException e) {
            e.printStackTrace();
            return null;
        }
    }
}

server:
  port: 8180
provider:
  ribbon:
    NFLoadBalancerRuleClassName: com.yqd.config.NacosWeightedRule

五、Sentinel 服务限流降级

雪崩效应--->降级、限流、熔断

解决方案：

1、设置线程超时

2、设置限流

3、熔断器 Sentinel、Hystrix

1、在服务提供者provider项目的pom.xml中加入依赖

<dependency>
    <groupId>com.alibaba.cloud</groupId>
    <artifactId>spring-cloud-starter-alibaba-sentinel</artifactId>
    <version>2.2.1.RELEASE</version>
</dependency>

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-actuator</artifactId>
</dependency>

2、在provider的application中增加配置

management:
  endpoints:
    web:
      exposure:
        include: '*'
spring:
  cloud:
    sentinel:
      transport:
        dashboard: localhost:8080

3、下载 Sentinel 控制台，解压，启动。访问地址：http://localhost:8080。用户名和密码都是sentinel。

4、启动nacos，再启动provider项目，访问provider中的接口，等待一会刷新会出现服务相关的信息。必须有请求时才可以监控到。

5.1 流控规则

直接限流：直接对某个接口限流

关联限流：对某个接口的访问会影响对另一个接口的访问

链路限流：可以通过链路入侵到其他层，比如controller层、service层

链路过滤相关代码：

1、在服务提供者provider项目的pom.xml中加入依赖

<dependency>
    <groupId>com.alibaba.csp</groupId>
    <artifactId>sentinel-core</artifactId>
    <version>1.7.1</version>
</dependency>

<dependency>
    <groupId>com.alibaba.csp</groupId>
    <artifactId>sentinel-web-servlet</artifactId>
    <version>1.7.1</version>
</dependency>

2、在provider的application中增加配置

spring:
	cloud:
        sentinel:
          filter:
            enabled: false

3、增加配置类

package com.southwind.configuration;

import com.alibaba.csp.sentinel.adapter.servlet.CommonFilter;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class FilterConfiguration {

    @Bean
    public FilterRegistrationBean registrationBean(){
        FilterRegistrationBean registrationBean = new FilterRegistrationBean();
        registrationBean.setFilter(new CommonFilter());
        registrationBean.addUrlPatterns("/*");
        registrationBean.addInitParameter(CommonFilter.WEB_CONTEXT_UNIFY,"false");
        registrationBean.setName("sentinelFilter");
        return registrationBean;
    }
}

4、Service

@Service
public class HelloService {

    @SentinelResource("test")
    public void test(){
        System.out.println("test");
    }
}

5、Controller

@Autowired
private HelloService helloService;

@GetMapping("/test1")
public String test1(){
    this.helloService.test();
    return "test1";
}

@GetMapping("/test2")
public String test2(){
    this.helloService.test();
    return "test2";
}

6、访问接口http://localhost:8081/test1和http://localhost:8081/test2。然后再sentinel控制台簇点链路会看到两个接口test1和test2。对test1接口增加一个流控，设置单机阈值=1，流控模式魏链路，入口资源为/test1，新增。然后再去分别刷新访问两个接口，会发现test1接口刷新太快会限流，test2接口不会限流。

5.2流控效果

快速失败

直接抛出异常

Warm UP

给系统一个预热的时间，预热时间段内单机阈值较低，预热时间过后单机阈值增加，预热时间内当前的单机阈值是设置的阈值的三分之一，预热时间过后单机阈值恢复设置的值。

排队等待

当请求调用失败之后，不会立即抛出异常，等待下一次调用，时间范围是超时时间，在时间范围内如果能请求成功则不抛出异常，如果请求则抛出异常。

5.3 降级规则

RT

单个请求的响应时间超过阈值，则进入准降级状态，接下来 1 S 内连续 5 个请求响应时间均超过阈值，就进行降级，持续时间为时间窗口的值。

异常比例

每秒异常数量占通过量的比例大于阈值，就进行降级处理，持续时间为时间窗口的值。

异常数

1 分钟内的异常数超过阈值就进行降级处理，时间窗口的值要大于 60S，否则刚结束熔断又进入下一次熔断了。

5.4 热点规则

热点规则是流控规则的更细粒度操作，可以具体到对某个热点参数的限流，设置限流之后，如果带着限流参数的请求量超过阈值，则进行限流，时间为统计窗口时长。

必须要添加 @SentinelResource，即对资源进行流控。

@GetMapping("/hot")
@SentinelResource("hot")
public String hot(
        @RequestParam(value = "num1",required = false) Integer num1,
        @RequestParam(value = "num2",required = false) Integer num2){
    return num1+"-"+num2;
}

5.5 授权规则

给指定的资源设置流控应用（追加参数），可以对流控应用进行访问权限的设置，具体就是添加白名单和黑名单。

如何给请求指定流控应用，通过实现 RequestOriginParser 接口来完成，代码如下所示。

package com.southwind.configuration;

import com.alibaba.csp.sentinel.adapter.servlet.callback.RequestOriginParser;
import org.springframework.util.StringUtils;

import javax.servlet.http.HttpServletRequest;

public class RequestOriginParserDefinition implements RequestOriginParser {
    @Override
    public String parseOrigin(HttpServletRequest httpServletRequest) {
        String name = httpServletRequest.getParameter("name");
        if(StringUtils.isEmpty(name)){
            throw new RuntimeException("name is null");
        }
        return name;
    }
}

要让 RequestOriginParserDefinition 生效，需要在配置类中进行配置。

package com.southwind.configuration;

import com.alibaba.csp.sentinel.adapter.servlet.callback.WebCallbackManager;
import org.springframework.context.annotation.Configuration;

import javax.annotation.PostConstruct;

@Configuration
public class SentinelConfiguration {

    @PostConstruct
    public void init(){
        WebCallbackManager.setRequestOriginParser(new RequestOriginParserDefinition());
    }
}

5.6 自定义规则异常返回

创建异常处理类

package com.southwind.handler;

import com.alibaba.csp.sentinel.adapter.servlet.callback.UrlBlockHandler;
import com.alibaba.csp.sentinel.slots.block.BlockException;
import com.alibaba.csp.sentinel.slots.block.degrade.DegradeException;
import com.alibaba.csp.sentinel.slots.block.flow.FlowException;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

public class ExceptionHandler implements UrlBlockHandler {
    @Override
    public void blocked(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, BlockException e) throws IOException {
        httpServletResponse.setContentType("text/html;charset=utf-8");
        String msg = null;
        if(e instanceof FlowException){
            msg = "限流";
        }else if(e instanceof DegradeException){
            msg = "降级";
        }
        httpServletResponse.getWriter().write(msg);
    }
}

进行配置。

@Configuration
public class SentinelConfiguration {

    @PostConstruct
    public void init(){
        WebCallbackManager.setUrlBlockHandler(new ExceptionHandler());
    }
}

六、整合 RocketMQ

6.1 安装 RocketMQ

1、传入 Linux 服务器

2、解压缩，把rocketmq的文件夹放到/usr/local/目录下

unzip rocketmq-all-4.7.1-bin-release.zip

3、切换到rockmq的目录中，启动 NameServer

nohup ./bin/mqnamesrv &

4、检查是否启动成功

netstat -an | grep 9876

5、启动 Broker

启动之前需要编辑配置文件，修改 JVM 内存设置，默认给的内存 4 GB，超过我们的 JVM 了。

cd bin
vim runserver.sh

改成如下参数：

JAVA_OPT="${JAVA_OPT} -server -Xms256m -Xmx256m -Xmn128m -XX:MetaspaceSize=128m -XX:MaxMetaspaceSize=320m"

vim runbroker.sh

改成如下参数：

JAVA_OPT="${JAVA_OPT} -server -Xms256m -Xmx256m -Xmn128m"

启动 Broker

nohup ./mqbroker -n localhost:9876 &

可以查看日志

tail -f ~/logs/rocketmqlogs/broker.log

启动成功

6、测试 RocketMQ

消息发送

cd bin
export NAMESRV_ADDR=localhost:9876
./tools.sh org.apache.rocketmq.example.quickstart.Producer

消息接收

cd bin
export NAMESRV_ADDR=localhost:9876
./tools.sh org.apache.rocketmq.example.quickstart.Consumer

7、关闭 RocketMQ

cd bin
./mqshutdown broker
./mqshutdown namesrv

6.2 安装 RocketMQ 控制台

1、把rocketmq的客户端文件解压缩，进入目录rocketmq-externals-rocketmq-console-1.0.0 ocketmq-consolesrcmain esources，修改配置application.yml，打包

mvn clean package -Dmaven.test.skip=true

2、进入 target 启动 jar

java -jar rocketmq-console-ng-1.0.0.jar 

打开浏览器访问 localhost:9877，如果报错

这是因为我们的 RocketMQ 安装在 Linux 中，控制台在 windows，Linux 需要开放端口才能访问，开放 10909 和 9876 端口

firewall-cmd --zone=public --add-port=9876/tcp --permanent
firewall-cmd --zone=public --add-port=10909/tcp --permanent
firewall-cmd --zone=public --add-port=10911/tcp --permanent
systemctl restart firewalld.service
firewall-cmd --reload

重新启动控制台项目

6.3 Java 实现消息发送

1、pom.xml 中引入依赖

<dependency>
    <groupId>org.apache.rocketmq</groupId>
    <artifactId>rocketmq-spring-boot-starter</artifactId>
    <version>2.1.0</version>
</dependency>

2、生产消息

package com.southwind;

import org.apache.rocketmq.client.producer.DefaultMQProducer;
import org.apache.rocketmq.client.producer.SendResult;
import org.apache.rocketmq.common.message.Message;

public class Test {
    public static void main(String[] args) throws Exception {
        //创建消息生产者
        DefaultMQProducer producer = new DefaultMQProducer("myproducer-group");
        //设置NameServer
        producer.setNamesrvAddr("192.168.248.129:9876");
        //启动生产者
        producer.start();
        //构建消息对象
        Message message = new Message("myTopic","myTag",("Test MQ").getBytes());
        //发送消息
        SendResult result = producer.send(message, 1000);
        System.out.println(result);
        //关闭生产者
        producer.shutdown();
    }
}

3、直接运行，如果报错 sendDefaultImpl call timeout，可以开放 10911 端口

firewall-cmd --zone=public --add-port=10911/tcp --permanent
systemctl restart firewalld.service
firewall-cmd --reload

打开 RocketMQ 控制台，可查看消息。

6.4 Java 实现消息消费

package com.southwind.service;

import lombok.extern.slf4j.Slf4j;
import org.apache.rocketmq.client.consumer.DefaultMQPushConsumer;
import org.apache.rocketmq.client.consumer.listener.ConsumeConcurrentlyContext;
import org.apache.rocketmq.client.consumer.listener.ConsumeConcurrentlyStatus;
import org.apache.rocketmq.client.consumer.listener.MessageListenerConcurrently;
import org.apache.rocketmq.client.exception.MQClientException;
import org.apache.rocketmq.common.message.MessageExt;

import java.util.List;

@Slf4j
public class ConsumerTest {
    public static void main(String[] args) throws MQClientException {
        //创建消息消费者
        DefaultMQPushConsumer consumer = new DefaultMQPushConsumer("myconsumer-group");
        //设置NameServer
        consumer.setNamesrvAddr("192.168.248.129:9876");
        //指定订阅的主题和标签
        consumer.subscribe("myTopic","*");
        //回调函数
        consumer.registerMessageListener(new MessageListenerConcurrently() {
            @Override
            public ConsumeConcurrentlyStatus consumeMessage(List<MessageExt> list, ConsumeConcurrentlyContext consumeConcurrentlyContext) {
                log.info("Message=>{}",list);
                return ConsumeConcurrentlyStatus.CONSUME_SUCCESS;
            }
        });
        //启动消费者
        consumer.start();
    }
}

6.5 Spring Boot 整合 RocketMQ

provider中添加内容

1、pom.xml

<dependency>
    <groupId>org.apache.rocketmq</groupId>
    <artifactId>rocketmq-spring-boot-starter</artifactId>
    <version>2.1.0</version>
</dependency>
<dependency>
    <groupId>org.apache.rocketmq</groupId>
    <artifactId>rocketmq-client</artifactId>
    <version>4.7.0</version>
</dependency>

2、application.yml

rocketmq:
  name-server: 192.168.248.129:9876
  producer:
    group: myprovider

3、Order

package com.southwind.entity;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

import java.util.Date;

@Data
@AllArgsConstructor
@NoArgsConstructor
public class Order {
    private Integer id;
    private String buyerName;
    private String buyerTel;
    private String address;
    private Date createDate;
}

4、Controller

@Autowired
private RocketMQTemplate rocketMQTemplate;

@GetMapping("/create")
public Order create(){
    Order order = new Order(
        1,
        "张三",
        "123123",
        "软件园",
        new Date()
    );
    this.rocketMQTemplate.convertAndSend("myTopic",order);
    return order;
}

consumer中添加内容

1、pom.xml

<dependency>
    <groupId>org.apache.rocketmq</groupId>
    <artifactId>rocketmq-spring-boot-starter</artifactId>
    <version>2.1.0</version>
</dependency>
<dependency>
    <groupId>org.apache.rocketmq</groupId>
    <artifactId>rocketmq-client</artifactId>
    <version>4.7.0</version>
</dependency>

2、application.yml

rocketmq:
  name-server: 192.168.248.129:9876

3、Service

@Slf4j
@Service
@RocketMQMessageListener(consumerGroup = "myConsumer",topic = "myTopic")
public class SmsService implements RocketMQListener<Order> {
    @Override
    public void onMessage(Order order) {
        log.info("新订单{},发短信",order);
    }
} 

先启动provider，再启动consumer。然后调用provider的接口产生消息：http://localhost:8081/create，消息会存入rocketmq服务器中，consumer一直监听着服务器，当服务器新存入消息的时候就从服务器中读取消息。可能会遇到无法读取消息的情况，可以重启一下consumer。

七、服务网关

Spring Cloud Gateway 是基于 Netty，跟 Servlet 不兼容，所以你的工程中不能出现 Servlet 的组件 。

1、pom.xml

注意，一定不能出现 spring web 的依赖，因为 Gateway 与 Servlet 不兼容。因此需要把spring-boot-starter-web依赖从父工程中添加到需要它的子工程中，这样gateway中就不会依赖到它了。

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-gateway</artifactId>
</dependency>

2、application.yml

server:
  port: 8010
spring:
  application:
    name: gateway
  cloud:
    gateway:
      discovery:
        locator:
          enabled: true
      routes: 
        - id: provider_route   
          uri: http://localhost:8081 
          predicates: 
            - Path=/provider/** 
          filters:
            - StripPrefix=1

上面这种做法其实没有用到 nacos ，现在我们让 gateway 直接去 nacos 中发现服务，配置更加简单了。

1、pom.xml 引入 nacos

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-gateway</artifactId>
</dependency>

<dependency>
    <groupId>com.alibaba.cloud</groupId>
    <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
</dependency>

2、application.yml

server:
  port: 8010
spring:
  application:
    name: gateway
  cloud:
      gateway:
        discovery:
          locator:
            enabled: true

7.1 Gateway 限流

7.1.1 基于路由限流

1、pom.xml

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-gateway</artifactId>
</dependency>

<dependency>
    <groupId>com.alibaba.csp</groupId>
    <artifactId>sentinel-spring-cloud-gateway-adapter</artifactId>
</dependency>

2、配置类

package com.southwind.configuration;

import com.alibaba.csp.sentinel.adapter.gateway.common.rule.GatewayFlowRule;
import com.alibaba.csp.sentinel.adapter.gateway.common.rule.GatewayRuleManager;
import com.alibaba.csp.sentinel.adapter.gateway.sc.SentinelGatewayFilter;
import com.alibaba.csp.sentinel.adapter.gateway.sc.callback.BlockRequestHandler;
import com.alibaba.csp.sentinel.adapter.gateway.sc.callback.GatewayCallbackManager;
import com.alibaba.csp.sentinel.adapter.gateway.sc.exception.SentinelGatewayBlockExceptionHandler;
import org.springframework.beans.factory.ObjectProvider;
import org.springframework.cloud.gateway.filter.GlobalFilter;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.Ordered;
import org.springframework.core.annotation.Order;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.http.codec.ServerCodecConfigurer;
import org.springframework.web.reactive.function.BodyInserters;
import org.springframework.web.reactive.function.server.ServerResponse;
import org.springframework.web.reactive.result.view.ViewResolver;
import org.springframework.web.server.ServerWebExchange;
import reactor.core.publisher.Mono;

import javax.annotation.PostConstruct;
import java.util.*;

@Configuration
public class GatewayConfiguration {
    private final List<ViewResolver> viewResolvers;
    private final ServerCodecConfigurer serverCodecConfigurer;


    public GatewayConfiguration(ObjectProvider<List<ViewResolver>> viewResolversProvider,
                                ServerCodecConfigurer serverCodecConfigurer) {
        this.viewResolvers = viewResolversProvider.getIfAvailable(Collections::emptyList);
        this.serverCodecConfigurer = serverCodecConfigurer;
    }

    //配置限流的异常处理
    @Bean
    @Order(Ordered.HIGHEST_PRECEDENCE)
    public SentinelGatewayBlockExceptionHandler sentinelGatewayBlockExceptionHandler() {
        return new SentinelGatewayBlockExceptionHandler(viewResolvers, serverCodecConfigurer);
    }

    //配置初始化的限流参数
    @PostConstruct
    public void initGatewayRules(){
        Set<GatewayFlowRule> rules = new HashSet<>();
        rules.add(
                new GatewayFlowRule("provider_route")
                .setCount(1)
                .setIntervalSec(1)
        );
        GatewayRuleManager.loadRules(rules);
    }

    //初始化限流过滤器
    @Bean
    @Order(Ordered.HIGHEST_PRECEDENCE)
    public GlobalFilter sentinelGatewayFilter() {
        return new SentinelGatewayFilter();
    }

    //自定义限流异常页面
    @PostConstruct
    public void initBlockHandlers(){
        BlockRequestHandler blockRequestHandler = new BlockRequestHandler() {
            @Override
            public Mono<ServerResponse> handleRequest(ServerWebExchange serverWebExchange, Throwable throwable) {
                Map map = new HashMap();
                map.put("code",0);
                map.put("msg","被限流了");
                return ServerResponse.status(HttpStatus.OK)
                        .contentType(MediaType.APPLICATION_JSON)
                        .body(BodyInserters.fromObject(map));
            }
        };
        GatewayCallbackManager.setBlockHandler(blockRequestHandler);
    }
}

3、application.yml

server:
  port: 8010
spring:
  application:
    name: gateway
  cloud:
    gateway:
      discovery:
        locator:
          enabled: true
      routes:
        - id: provider_route
          uri: http://localhost:8081
          predicates:
            - Path=/provider/**
          filters:
            - StripPrefix=1

7.1.2 基于 API 分组限流

1、修改配置类，添加基于 API 分组限流的方法，修改初始化的限流参数

package com.southwind.configuration;

import com.alibaba.csp.sentinel.adapter.gateway.common.SentinelGatewayConstants;
import com.alibaba.csp.sentinel.adapter.gateway.common.api.ApiDefinition;
import com.alibaba.csp.sentinel.adapter.gateway.common.api.ApiPathPredicateItem;
import com.alibaba.csp.sentinel.adapter.gateway.common.api.ApiPredicateItem;
import com.alibaba.csp.sentinel.adapter.gateway.common.api.GatewayApiDefinitionManager;
import com.alibaba.csp.sentinel.adapter.gateway.common.rule.GatewayFlowRule;
import com.alibaba.csp.sentinel.adapter.gateway.common.rule.GatewayRuleManager;
import com.alibaba.csp.sentinel.adapter.gateway.sc.SentinelGatewayFilter;
import com.alibaba.csp.sentinel.adapter.gateway.sc.callback.BlockRequestHandler;
import com.alibaba.csp.sentinel.adapter.gateway.sc.callback.GatewayCallbackManager;
import com.alibaba.csp.sentinel.adapter.gateway.sc.exception.SentinelGatewayBlockExceptionHandler;
import org.springframework.beans.factory.ObjectProvider;
import org.springframework.cloud.gateway.filter.GlobalFilter;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.Ordered;
import org.springframework.core.annotation.Order;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.http.codec.ServerCodecConfigurer;
import org.springframework.web.reactive.function.BodyInserters;
import org.springframework.web.reactive.function.server.ServerResponse;
import org.springframework.web.reactive.result.view.ViewResolver;
import org.springframework.web.server.ServerWebExchange;
import reactor.core.publisher.Mono;

import javax.annotation.PostConstruct;
import java.util.*;

@Configuration
public class GatewayConfiguration {

    private final List<ViewResolver> viewResolvers;
    private final ServerCodecConfigurer serverCodecConfigurer;


    public GatewayConfiguration(ObjectProvider<List<ViewResolver>> viewResolversProvider,
                                ServerCodecConfigurer serverCodecConfigurer) {
        this.viewResolvers = viewResolversProvider.getIfAvailable(Collections::emptyList);
        this.serverCodecConfigurer = serverCodecConfigurer;
    }

    //配置限流的异常处理
    @Bean
    @Order(Ordered.HIGHEST_PRECEDENCE)
    public SentinelGatewayBlockExceptionHandler sentinelGatewayBlockExceptionHandler() {
        return new SentinelGatewayBlockExceptionHandler(viewResolvers, serverCodecConfigurer);
    }

    //配置初始化的限流参数
    @PostConstruct
    public void initGatewayRules(){
        Set<GatewayFlowRule> rules = new HashSet<>();
        rules.add(new GatewayFlowRule("provider_api1").setCount(1).setIntervalSec(1));
        rules.add(new GatewayFlowRule("provider_api2").setCount(1).setIntervalSec(1));
        GatewayRuleManager.loadRules(rules);
    }

    //初始化限流过滤器
    @Bean
    @Order(Ordered.HIGHEST_PRECEDENCE)
    public GlobalFilter sentinelGatewayFilter() {
        return new SentinelGatewayFilter();
    }

    //自定义限流异常页面
    @PostConstruct
    public void initBlockHandlers(){
        BlockRequestHandler blockRequestHandler = new BlockRequestHandler() {
            @Override
            public Mono<ServerResponse> handleRequest(ServerWebExchange serverWebExchange, Throwable throwable) {
                Map map = new HashMap();
                map.put("code",0);
                map.put("msg","被限流了");
                return ServerResponse.status(HttpStatus.OK)
                        .contentType(MediaType.APPLICATION_JSON)
                        .body(BodyInserters.fromObject(map));
            }
        };
        GatewayCallbackManager.setBlockHandler(blockRequestHandler);
    }

    //自定义API分组
    @PostConstruct
    private void initCustomizedApis(){
        Set<ApiDefinition> definitions = new HashSet<>();
        ApiDefinition api1 = new ApiDefinition("provider_api1")
                .setPredicateItems(new HashSet<ApiPredicateItem>(){{
                    add(new ApiPathPredicateItem().setPattern("/provider/api1/**")
                            .setMatchStrategy(SentinelGatewayConstants.URL_MATCH_STRATEGY_PREFIX));
                }});
        ApiDefinition api2 = new ApiDefinition("provider_api2")
                .setPredicateItems(new HashSet<ApiPredicateItem>(){{
                    add(new ApiPathPredicateItem().setPattern("/provider/api2/demo1"));
                }});
        definitions.add(api1);
        definitions.add(api2);
        GatewayApiDefinitionManager.loadApiDefinitions(definitions);
    }
}

2、在provider的Controller中添加方法

@GetMapping("/api1/demo1")
public String demo1(){
    return "demo";
}

@GetMapping("/api1/demo2")
public String demo2(){
    return "demo";
}

@GetMapping("/api2/demo1")
public String demo3(){
    return "demo";
}

@GetMapping("/api2/demo2")
public String demo4(){
    return "demo";
}

7.1.3 基于 Nacos 服务发现组件进行限流

server:
  port: 8010
spring:
  application:
    name: gateway
  cloud:
    gateway:
      discovery:
        locator:
          enabled: true

API 分组代码修改，改为 discovery 中的服务名。

ApiDefinition api2 = new ApiDefinition("provider_api2")
        .setPredicateItems(new HashSet<ApiPredicateItem>(){{
            add(new ApiPathPredicateItem().setPattern("/p1/api2/demo1"));
        }});

八、分布式事务

8.1 模拟分布式事务异常

1、创建两个工程 order、pay，pom.xml

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-jdbc</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>

<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <scope>runtime</scope>
</dependency>
<dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
    <optional>true</optional>
</dependency>

2、建两个数据库 order、pay，两个微服务分别访问。

order数据库里面建一个表orders，字段有id和username。

pay数据库里面建一个表pay，字段有id和username。

3、分别写两个服务的 application.yml

server:
  port: 8010
spring:
  application:
    name: order
  datasource:
    driver-class-name: com.mysql.cj.jdbc.Driver
    username: root
    password: 123456
    url: jdbc:mysql://localhost:3306/order?useUnicode=true&characterEncoding=utf-8&useSSL=false&serverTimezone=UTC

server:
  port: 8020
spring:
  application:
    name: pay
  datasource:
    driver-class-name: com.mysql.cj.jdbc.Driver
    username: root
    password: 123456
    url: jdbc:mysql://localhost:3306/pay?useUnicode=true&characterEncoding=utf-8&useSSL=false&serverTimezone=UTC

4、分别写两个 Service

package com.southwind.service;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.stereotype.Service;

@Service
public class OrderService {
    @Autowired
    private JdbcTemplate jdbcTemplate;

    public void save(){
        this.jdbcTemplate.update("insert into orders(username) values ('张三')");
    }
}

package com.southwind.service;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.stereotype.Service;

@Service
public class PayService {
    @Autowired
    private JdbcTemplate jdbcTemplate;

    public void save(){
        this.jdbcTemplate.update("insert into pay(username) values ('张三')");
    }
}

5、控制器 Order 通过 RestTemplate 调用 Pay 的服务

package com.southwind.controller;

import com.southwind.service.OrderService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

@RestController
public class OrderController {

    @Autowired
    private OrderService orderService;
    @Autowired
    private RestTemplate restTemplate;

    @GetMapping("/save")
    public String save(){
        //订单
        this.orderService.save();
        int i = 10/0;
        //支付
        this.restTemplate.getForObject("http://localhost:8020/save",String.class);
        return "success";
    }
}

package com.southwind.controller;

import com.southwind.service.PayService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class PayController {
    @Autowired
    private PayService payService;

    @GetMapping("/save")
    public String save(){
        this.payService.save();
        return "success";
    }
}

6、启动类

package com.southwind;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.web.client.RestTemplate;

@SpringBootApplication
public class OrderApplication {

    public static void main(String[] args) {
        SpringApplication.run(OrderApplication.class, args);
    }

    @Bean
    public RestTemplate restTemplate(){
        return new RestTemplate();
    }
}

package com.southwind;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class PayApplication {

    public static void main(String[] args) {
        SpringApplication.run(PayApplication.class, args);
    }

}

分布式异常模拟结束，Order 存储完成之后，出现异常，会导致 Pay 无法存储，但是 Order 数据库不会进行回滚。

8.2 Seata 解决

1、下载

2、解压，进入到conf文件夹下修改两个文件

regisry.conf

registry {
  type = "nacos"
  nacos {
    serverAddr = "localhost"
    namespace = "public"
    cluster = "default"
  }
}

config {
  type = "nacos"
  nacos {
    serverAddr = "localhost"
    namespace = "public"
    cluster = "default"
  }
}

nacos-config.txt

3、启动 Nacos，通过git bish的命令行窗口来运行 nacos-config.sh，将 Seata 配置导入 Nacos

进入 conf，右键 Git Bash Here

cd conf
sh nacos-config.sh 127.0.0.1

执行成功，刷新 Nacos，配置加入

nacos-config.txt 配置已生效

4、启动 Seata Server， JDK 8 以上环境无法启动

cd bin
seata-server.bat -p 8090 -m file

启动成功，Nacos 注册成功。

Seata 服务环境搭建完毕，接下来去应用中添加。

1、初始化数据库，在两个数据库中添加事务日志记录表，SQL Seata 已经提供。复制conf文件夹下db_undo_log.sql中的建表语句分别在order数据库和pay数据库中新建undo_log表。

2、直接在两个数据库运行脚本。

CREATE TABLE `undo_log` (
  `id` bigint(20) NOT NULL AUTO_INCREMENT,
  `branch_id` bigint(20) NOT NULL,
  `xid` varchar(100) NOT NULL,
  `context` varchar(128) NOT NULL,
  `rollback_info` longblob NOT NULL,
  `log_status` int(11) NOT NULL,
  `log_created` datetime NOT NULL,
  `log_modified` datetime NOT NULL,
  `ext` varchar(100) DEFAULT NULL,
  PRIMARY KEY (`id`),
  UNIQUE KEY `ux_undo_log` (`xid`,`branch_id`)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;

3、两个工程的 pom.xml 添加 Seata 组件和 Nacos Config 组件。

<dependency>
    <groupId>com.alibaba.cloud</groupId>
    <artifactId>spring-cloud-starter-alibaba-seata</artifactId>
    <version>2.1.1.RELEASE</version>
</dependency>

<dependency>
    <groupId>com.alibaba.cloud</groupId>
    <artifactId>spring-cloud-starter-alibaba-nacos-config</artifactId>
</dependency>

4、给 JDBCTemplate 添加代理数据源，因为本地数据源无法通知两个不同的数据库使用代理数据源才可以

package com.southwind;

import io.seata.rm.datasource.DataSourceProxy;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.web.client.RestTemplate;

import javax.sql.DataSource;

@SpringBootApplication
public class OrderApplication {

    public static void main(String[] args) {
        SpringApplication.run(OrderApplication.class, args);
    }

    @Bean
    public RestTemplate restTemplate(){
        return new RestTemplate();
    }

    @Bean
    public JdbcTemplate jdbcTemplate(DataSource dataSource){
        return new JdbcTemplate(new DataSourceProxy(dataSource));
    }
}

package com.southwind;

import io.seata.rm.datasource.DataSourceProxy;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.jdbc.core.JdbcTemplate;

import javax.sql.DataSource;

@SpringBootApplication
public class PayApplication {

    public static void main(String[] args) {
        SpringApplication.run(PayApplication.class, args);
    }

    @Bean
    public JdbcTemplate jdbcTemplate(DataSource dataSource){
        return new JdbcTemplate(new DataSourceProxy(dataSource));
    }

}

5、将 registry.conf 复制到两个工程的 resources 下。

6、给两个工程添加 bootstrap.yml 读取 Nacos 配置。

spring:
  application:
    name: order
  cloud:
    nacos:
      config:
        server-addr: localhost:8848
        namespace: public
        group: SEATA_GROUP
    alibaba:
      seata:
        tx-service-group: ${spring.application.name}

spring:
  application:
    name: pay
  cloud:
    nacos:
      config:
        server-addr: localhost:8848
        namespace: public
        group: SEATA_GROUP
    alibaba:
      seata:
        tx-service-group: ${spring.application.name}

tx-service-group 需要和 Nacos 配置中的名称一致。

7、在 Order 调用 Pay 处添加注解 @GlobalTransactional

package com.southwind.controller;

import com.southwind.service.OrderService;
import io.seata.spring.annotation.GlobalTransactional;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

@RestController
public class OrderController {

    @Autowired
    private OrderService orderService;
    @Autowired
    private RestTemplate restTemplate;

    @GetMapping("/save")
    @GlobalTransactional
    public String save(){
        //订单
        this.orderService.save();
        int i = 10/0;
        //支付
        this.restTemplate.getForObject("http://localhost:8020/save",String.class);
        return "success";
    }
}