dubbo系列(一)

进入官网之后，找到

http://dubbo.apache.org/en-us/docs/user/quick-start.html

有一个链接跳转到这里

http://dubbo.apache.org/en-us/docs/admin/install/provider-demo.html

使用git将项目下载下来

修改如下Service实现类

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.dubbo.demo.provider;

import org.apache.dubbo.demo.DemoService;
import org.apache.dubbo.demo.TestForm;
import org.apache.dubbo.rpc.RpcContext;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Date;
import java.util.List;

public class DemoServiceImpl implements DemoService {
    private static Logger logger= LoggerFactory.getLogger(DemoServiceImpl.class);
    @Override
    public String sayHello(String name) {
        System.out.println("[" + new SimpleDateFormat("HH:mm:ss").format(new Date()) + "] Hello " + name + ", request from consumer: " + RpcContext.getContext().getRemoteAddress());
        return "Hello " + name + ", response from provider: " + RpcContext.getContext().getLocalAddress();
    }

    @Override
    public List<TestForm> tranForm(TestForm testForm) {
        if(testForm==null){
            return Collections.emptyList();
        }
        logger.info("当前在{} 执行",RpcContext.getContext().getLocalAddress());
        List<TestForm> testFormList=new ArrayList<>(1);
        testFormList.add(testForm);
        return testFormList;
    }

}

tranForm()是我新增的，TestForm 是一个普通的实体类

public class TestForm implements Serializable{
    private boolean b;
    private String s;
    private Integer i;
    private BigDecimal bigDecimal;
    private  Double d;
//这里省略get set方法 构造方法
}

修改dubbo-demo/dubbo-demo-consumer/的Consumer 类

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.dubbo.demo.consumer;

import com.alibaba.fastjson.JSON;
import org.apache.dubbo.demo.DemoService;
import org.apache.dubbo.demo.TestForm;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import java.math.BigDecimal;
import java.util.List;

public class Consumer {
    private static Logger logger= LoggerFactory.getLogger(Consumer.class);

    /**
     * To get ipv6 address to work, add
     * System.setProperty("java.net.preferIPv6Addresses", "true");
     * before running your application.
     */
    public static void main(String[] args) {
        ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext(new String[]{"META-INF/spring/dubbo-demo-consumer.xml"});
        context.start();
        DemoService demoService = (DemoService) context.getBean("demoService"); // get remote service proxy
        int i=10;
        while (i-->0) {
            try {
                List<TestForm> testFormList = demoService.tranForm(new TestForm(true,"s",i,new BigDecimal(99),null)); // call remote method
                logger.info("序号:{}:返回内容:{}",i,JSON.toJSON(testFormList)); // get result
            } catch (Throwable throwable) {
                throwable.printStackTrace();
            }
        }
    }
}

修改 <dubbo:protocol name="dubbo" port="端口号"/> 运行Provider中的main方法 ，依次启动三个provider服务，端口号分别是 20880，20881，20882

运行Consumer中main方法,查看日志可以看出，Consumer分布式调用Provider已经成功了

 这个demo中，一共有三个模块

dubbo-demo-api 定义Service接口

dubbo-demo-consumer 传递实参调用Service

dubbo-demo-provider 定义Service实现类

        在consumer配置文件中，没有定义DemoService的实现类（文件路径：dubbo-demodubbo-demo-consumersrcmain esourcesMETA-INFspringdubbo-demo-consumer.xml）

而与DemoService相关的有这样的一个配置，我猜是dubbo创建了DemoService的bean并且放到了spring容器里，下面证实一个我的猜想：

 <dubbo:reference id="demoService" check="false" interface="org.apache.dubbo.demo.DemoService"/>

通过日志输入demoService的类型

logger.info("demoService实际类型：{}",demoService.getClass().getName());

[28/09/18 11:29:58:058 CST] main  INFO consumer.Consumer: demoService实际类型：org.apache.dubbo.common.bytecode.proxy0

打开 org.apache.dubbo.common.bytecode.Proxy 类，可以看到代理就是在这里创建的，继承了org.apache.dubbo.common.bytecode.Proxy抽象类

那么这个代理有什么用呢？未完待续