【Thrift二】Thrift版的Hello World

本篇，不考虑细节问题和为什么，先照葫芦画瓢写一个Thrift版本的Hello World，了解Thrift RPC服务开发的基本流程

1. 在Intellij中创建一个Maven模块，加入对Thrift的依赖，同时还要加上slf4j依赖，如果不加slf4j依赖，在后面启动Thrift Server时会报错

        <dependency>
            <groupId>org.apache.thrift</groupId>
            <artifactId>libthrift</artifactId>
            <version>0.9.1</version>
        </dependency>
       <dependency>
	   <groupId>org.slf4j</groupId>
	   <artifactId>slf4j-api</artifactId>
	   <version>1.7.7</version>
       </dependency>

2. 在resources目录下创建接口定义文件helloworld.thrift文件，内容如下

namespace java com.tom.thrift.hello

service  IHelloWorldService {
  string sayHello(1:string username)
}

3.在命令号终端cd到helloworld.thrift所在的目录，执行如下命令

thrift -r -gen java helloworld.thrift

4. 命令执行完成后，在当前目录下生成一个gen-java目录，其目录结构为 gen-java/com/tom/thrift/hello/IHelloWorldService.java,这么一个简单的接口声明，自动生成了957行代码。。复杂！！！

5.使用cp -r命令将com/tom/thrift/hello/IHelloWorldService.java目录连同文件copy到Maven模块的src/java/main下面

6.在Maven模块中，自定义IHelloWorldService的实现类HelloWorldService,需要实现IHelloWorldService.Iface接口，不出意料，果然仅仅需要实现sayHello方法，类定义如下：

package com.tom.thrift.hello;

import org.apache.thrift.TException;

public class HelloWorldService implements IHelloWorldService.Iface {
    @Override
    public String sayHello(String username) throws TException {
        return "Hi, " + username + ", Welcome to the Thrift world, enjoy it!";
    }
}

 10.自定义单线程模式的ThriftServer用于响应客户端的rpc请求，注意一点，IHelloWorldService.Iface的实现类在服务器端进行了实例化

package com.tom.thrift.hello;

import org.apache.thrift.TProcessor;
import org.apache.thrift.protocol.TBinaryProtocol;
import org.apache.thrift.server.TServer;
import org.apache.thrift.server.TSimpleServer;
import org.apache.thrift.transport.TServerSocket;

public class HelloWorldSimpleServer {
    public static final int SERVER_PORT = 8090;

    public void startServer() {
        try {
            System.out.println("HelloWorld TSimpleServer start ....");

            TProcessor tprocessor = new IHelloWorldService.Processor<IHelloWorldService.Iface>(
                    new HelloWorldService());
            // 简单的单线程服务模型，一般用于测试
            TServerSocket serverTransport = new TServerSocket(SERVER_PORT);
            TServer.Args tArgs = new TServer.Args(serverTransport);
            tArgs.processor(tprocessor);
            tArgs.protocolFactory(new TBinaryProtocol.Factory());
            // tArgs.protocolFactory(new TCompactProtocol.Factory());
            // tArgs.protocolFactory(new TJSONProtocol.Factory());
            TServer server = new TSimpleServer(tArgs);
            server.serve();

        } catch (Exception e) {
            System.out.println("Server start error!!!");
            e.printStackTrace();
        }
    }

    /**
     * @param args
     */
    public static void main(String[] args) {
        HelloWorldSimpleServer server = new HelloWorldSimpleServer();
        server.startServer();
    }

}

 11.自定义HelloWorld的客户端，用于远程调用第10步Thrift Server提供的IHelloWorldService服务

package com.tom.thrift.hello;

import org.apache.thrift.TException;
import org.apache.thrift.protocol.TBinaryProtocol;
import org.apache.thrift.protocol.TProtocol;
import org.apache.thrift.transport.TSocket;
import org.apache.thrift.transport.TTransport;
import org.apache.thrift.transport.TTransportException;

public class HelloWorldSimpleClient {

	public static final String SERVER_IP = "localhost";
	public static final int SERVER_PORT = 8090;//Thrift server listening port
	public static final int TIMEOUT = 30000;

	/**
	 *
	 * @param userName
	 */
	public void startClient(String userName) {
		TTransport transport = null;
		try {
			transport = new TSocket(SERVER_IP, SERVER_PORT, TIMEOUT);
			// 协议要和服务端一致
			TProtocol protocol = new TBinaryProtocol(transport);
			// TProtocol protocol = new TCompactProtocol(transport);
			// TProtocol protocol = new TJSONProtocol(transport);
			IHelloWorldService.Client client = new IHelloWorldService.Client(protocol);
			transport.open();
			String result = client.sayHello(userName);
			System.out.println("Thrift client result =: " + result);
		} catch (TTransportException e) {
			e.printStackTrace();
		} catch (TException e) {
			e.printStackTrace();
		} finally {
			if (null != transport) {
				transport.close();
			}
		}
	}

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		HelloWorldSimpleClient client = new HelloWorldSimpleClient();
		client.startClient("Tom");
	}
}

12.启动HelloWorldSimpleServer，控制台输出HelloWorld TSimpleServer start ....，同时，HelloWorldSimpleServer作为Server一直处于运行过程中

13.启动HelloWorldSimpleClient，控制台输出Thrift client result =: Hi, Tom, Welcome to the Thrift world, enjoy it! 执行完后，客户端进程结束

总结

 前面一步一步的完成了Thrift版本的Hello World，对Thrift开发RPC服务器，有了一个基本的了解。Thrift本身的细节和更深入的学习，将在后面继续。

本文参考：http://www.micmiu.com/soa/rpc/thrift-sample/