吴裕雄--天生自然--SPRING BOOT--自定义端点

Spring Boot提供了注解@Endpoint供我们定义一个端点类，并在端点类的方法上使用@ReadOperation注解来显示监控信息（对应Get请求），使用@WriteOperation来动态更新监控信息（对应Post请求，可以是rest-client-master访问）。

自定义端点(演示显示数据源的相关信息)

1．创建基于Spring Data JPA和Spring Boot Actuator的Web应用ch10_2
2．修改pom.xml文件添加MySQL依赖
3．配置数据源
4．自定义端点
5．暴露端点
6．测试端点

<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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.endpoint</groupId>
    <artifactId>SpringBootEndPoint</artifactId>
    <version>0.0.1-SNAPSHOT</version>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.0.RELEASE</version>
        <relativePath /> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <!-- 声明项目配置依赖编码格式为 utf-8 -->
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <fastjson.version>1.2.24</fastjson.version>
    </properties>

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

        <!-- 添加MySQL依赖 -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
            <version>8.0.13</version><!--$NO-MVN-MAN-VER$ -->
        </dependency>

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

    <build>
        <plugins>
            <plugin>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

spring.datasource.url=jdbc:mysql://localhost:3306/springbootjpa?serverTimezone=UTC&autoReconnect=true
spring.datasource.username=root
spring.datasource.password=admin
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.jpa.database=MYSQL
spring.jpa.show-sql=true
spring.jpa.hibernate.ddl-auto=update
spring.jackson.serialization.indent-output=true
management.endpoints.web.exposure.include=*
management.endpoint.health.show-details=always

package com.ch.ch10_2.endPoint;

import java.util.HashMap;
import java.util.Map;
import org.springframework.boot.actuate.endpoint.annotation.Endpoint;
import org.springframework.boot.actuate.endpoint.annotation.ReadOperation;
import org.springframework.boot.actuate.endpoint.annotation.WriteOperation;
import org.springframework.stereotype.Component;
import com.zaxxer.hikari.HikariConfigMXBean;
import com.zaxxer.hikari.HikariDataSource;
import com.zaxxer.hikari.HikariPoolMXBean;

//注册为端点，id不能使用驼峰法（dataSource），需要以-分割
@Endpoint(id = "data-source")
@Component
public class DataSourceEndpoint {
    // HikariDataSource提供多个监控信息
    HikariDataSource ds;

    public DataSourceEndpoint(HikariDataSource ds) {
        this.ds = ds;
    }

    @ReadOperation
    public Map<String, Object> info() {
        Map<String, Object> map = new HashMap<String, Object>();
        // 连接池配置
        HikariConfigMXBean configBean = ds.getHikariConfigMXBean();
        map.put("max", configBean.getMaximumPoolSize());
        // 连接池运行状态
        HikariPoolMXBean mxBean = ds.getHikariPoolMXBean();
        map.put("active", mxBean.getActiveConnections());
        map.put("idle", mxBean.getIdleConnections());
        // 连接池无连接时，等待获取连接的线程个数
        map.put("wait", mxBean.getThreadsAwaitingConnection());
        return map;
    }

    @WriteOperation
    public void setMax(int max) {
        ds.getHikariConfigMXBean().setMaximumPoolSize(max);
    }
}

5．暴露端点

在配置文件application.properties中暴露端点，内容如下：
    #暴露所有端点，当然包括data-source，我们也可以只暴露data-source端点
management.endpoints.web.exposure.include=*

package com.ch.ch10_2;

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

@SpringBootApplication
public class Ch102Application {
    public static void main(String[] args) {
        SpringApplication.run(Ch102Application.class, args);
    }
}

6．测试端点

首先，启动应用程序主类Ch102Application，然后通过“http://localhost:8080/actuator/data-source”测试端点data-source

使用rest-client-master发送POST请求“http://localhost:8080/actuator/data-source?max=20”

POST请求“http://localhost:8080/actuator/data-source?max=20”执行后，“http://localhost:8080/actuator/data-source”测试端点data-source