Java实现一个简单的RPC框架(六) 注册机制

注册

就是Server要声明支持那些RPC方法，比如我们之前Server支持‘sayHello’和‘add’方法，其它的方法就无法识别。

我们是之前把注册功能写在了procRequest函数中，但是这样写的话，我么每次新增一个rpc方法的时候就需要修改这个函数，如何避免？引入服务注册机制。

String procRequest(String reqStr){//return "Hello World";mRequest req =decode(reqStr);mResponse rsp = new mResponse();rsp.id = req.id;if(req.command.equals("sayHello")){rsp.result = "Hello";}else if(req.command.equals("add")){rsp.result = Integer.toString(req.arg1+req.arg2);}else{System.out.println("req command"+req.command);rsp.result = "unknown command";}return encode(rsp);}

服务注册机制，就是将command与具体的function object绑定起来，生成第一dict。

｛‘sayHello’:sayHello,'add':add｝

有了dict，每次收到req，只要提取出command字段，就可以从dict中找出对应的function，调用该function即可。

Java代码实现：

Client.java不变

import java.io.BufferedReader;import java.io.BufferedWriter;import java.io.IOException;import java.io.InputStreamReader;import java.io.PrintWriter;import java.net.Socket;import java.net.UnknownHostException;public class Client {public static void main(String[] args) {mClient client = new mClient();client.setReqId(1);client.setReqCommand("sayHello");String reqStr = client.req.getRequest();try {Socket socket = new Socket("localhost",12345);PrintWriter out = new PrintWriter(socket.getOutputStream());//将reqStr传给serverout.println(reqStr);out.flush();BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));//while(){String rspStr = in.readLine();System.out.println("response form Server:"+rspStr);client.rsp = client.decode(rspStr);System.out.println("decode result:"+client.rsp.result);}//BufferedReader in = new BufferedReader(in)//socket.close();} catch (UnknownHostException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();}}}class mResponse{int id;String result;String getResponse(){return "id"+id+"result"+result;}}class mRequest{int id;String command;int arg1;int arg2;String getRequest(){return "req:id"+id+"command"+command+"arg1"+arg1+"arg2"+arg2;}}class mClient{mServer remote;mRequest req = new mRequest();String reqStr = req.getRequest();mResponse rsp = new mResponse();void setReqId(int id){req.id=id;}void setReqCommand(String command){req.command=command;}mClient(){remote = null;}String getRsp(String reqStr){String rspStr = remote.procRequest(reqStr);mResponse rsp=decode(rspStr);return rsp.result;}String sayHello(){req.id=1;req.command="sayHello";//req.getRequest()return getRsp(req.getRequest());}String add(int a,int b){req.id=1;req.command="add";req.arg1=a;req.arg2=b;return getRsp(req.getRequest());}mResponse decode(String rspStr){mResponse response = new mResponse();if(!rspStr.startsWith("rsp:")){System.out.println("it is not a response data");}else{response.id=Integer.parseInt(rspStr.substring(rspStr.indexOf("id")+2, rspStr.indexOf("result")));response.result=rspStr.substring(rspStr.indexOf("result")+6);}return response;}}

Server.java修改procRequest函数

import java.io.BufferedReader;import java.io.IOException;import java.io.InputStreamReader;import java.io.PrintWriter;import java.net.ServerSocket;import java.net.Socket;import javax.swing.JOptionPane;import com.sun.corba.se.impl.legacy.connection.SocketFactoryContactInfoListImpl;public class Server {//基于socket实现传输层public static void main(String[] args) {mServer server = new mServer();//server监听的端口号//port取值范围1-65535，这个server监听的端口号，一般指定较大的数值，这样可以和系统预留的端口号分开int port=12345;ServerSocket serverSocket = null;try {serverSocket = new ServerSocket(port);Socket socket = serverSocket.accept();//提示建立链接JOptionPane.showMessageDialog(null, "有客户端链接到本机的12345端口");BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));//while(true){String msgFromClient=in.readLine();System.out.println("Server print recived msg:"+msgFromClient);String reqStr = msgFromClient;String rspStr = server.procRequest(reqStr);PrintWriter out = new PrintWriter(socket.getOutputStream());out.println(rspStr);out.flush();}socket.close();} catch (IOException e) {e.printStackTrace();}}}/*class mResponse{int id;String result;String getResponse(){return "id"+id+"result"+result;}}class mRequest{int id;String command;int arg1;int arg2;String getRequest(){return "req:id"+id+"command"+command+"arg1"+arg1+"arg2"+arg2;}}*/class mServer{//Server解析收到的Request报文（报文由id和command组成）//将回复报文id设置为收到的报文一致//如果command为sayHello，那么范围的报文内容为Hello//如果为其他命令，我们暂时没有设定，所有输出无法解析提示消息unknown commandString procRequest(String reqStr){//return "Hello World";mRequest req =decode(reqStr);mResponse rsp = new mResponse();rsp.id = req.id;//if(req.command.equals("sayHello"))//{//rsp.result = "Hello";//}else if(req.command.equals("add"))//{//rsp.result = Integer.toString(req.arg1+req.arg2);//}//else//{//System.out.println("req command"+req.command);//rsp.result = "unknown command";//}ServiceRegister register = new ServiceRegister(req);register.resigte(req.command);rsp.result = register.getService(req.command);return encode(rsp);}//rspStr格式：rsp:id+@id+result+@resultString encode(mResponse response){String rspStr;rspStr="rsp:id"+response.id+"result"+response.result;return rspStr;}//reqStr格式：req:id+@id+command+@command+arg1+@arg1+arg2+@arg2mRequest decode(String reqStr){//System.out.println("serverdecode reqStr:"+reqStr);mRequest request = new mRequest();if(!reqStr.startsWith("req:")){System.err.println("it is not a request data");}else{request.id=Integer.parseInt(reqStr.substring(reqStr.indexOf("id")+2,reqStr.indexOf("command")));request.command=reqStr.substring(reqStr.indexOf("command")+7, reqStr.indexOf("arg1"));//System.out.println("server decode command:"+request.command);request.arg1=Integer.parseInt(reqStr.substring(reqStr.indexOf("arg1")+4, reqStr.indexOf("arg2")));request.arg2=Integer.parseInt(reqStr.substring(reqStr.indexOf("arg2")+4));}return request;}}

新增注册类ServiceRegister.java

import java.util.HashMap;/** * 通过register（）去注册服务，通过get_service（）去获取服务名对应的function * @author xchen * */public class ServiceRegister {int arg1;int arg2;HashMap<String, String> hm = new HashMap<>();void resigte(String servicename){if(hm.containsKey(servicename)){System.out.println("service is already exist!do have to resigter");}else{hm.put(servicename,servicename);}}public ServiceRegister(mRequest request) {this.arg1 = request.arg1;this.arg2 = request.arg2;}Services services = new Services(arg1, arg2);String getService(String callName){String functionN=hm.get(callName);return doMethod(functionN);}String doMethod(String functionN){if(functionN.equals("sayHello")){return services.sayHello();}if(functionN.equals("add")){return services.add();}return null;}}class Services{int id;int arg1;int arg2;public Services(int arg1,int arg2) {this.arg1=arg1;this.arg2=arg2;}String sayHello(){return "Hello";}String add(){return Integer.toString(arg1+arg2);}}

运行一下：