java Socket通信的学习笔记三

 先看一段服务器端的代码：

package com.socket.test;

import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;

public class Server {

	public static void main(String[] args) {
		try {
			System.out.println("开始侦听请求。。。。");
			ServerSocket serverSocket=new ServerSocket(3333);//服务器套接字
			Socket clientSocket=null;
			while(true){
				
				clientSocket=serverSocket.accept();//获得客户端的请求的Socket
				System.out.println("已侦听到了客户端的请求。。。。。");
				new ServerThread(clientSocket);
			}
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}

}

 下面是ServerThread的代码：

package com.socket.test;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.net.Socket;

public class ServerThread extends Thread {
	
	private Socket socket;
	private InputStream  clientInput;
	private OutputStream clientOutput;
	
	public ServerThread(Socket socket){
			this.socket=socket;
		try {
			this.clientInput=socket.getInputStream();
			this.clientOutput=socket.getOutputStream();
		} catch (IOException e) {
			e.printStackTrace();
		}
		this.start();
	}
	
	@Override
	public void run() {
		System.out.println("this is child class's run method.....");
		BufferedReader breader=new BufferedReader(new InputStreamReader(clientInput));
		try {
			String strLine=breader.readLine();
			if("over".equalsIgnoreCase(strLine)){
				PrintWriter printWriter=new PrintWriter(clientOutput,true);
				printWriter.println("over");
			}else{
				double side=Double.parseDouble(strLine);
				side=Double.parseDouble(strLine);
				System.out.println("Side of Square Received:"+side);
				double squareArea=side*side;
				String str="Side:"+side+"Square:"+squareArea;
				PrintWriter printWriter=new PrintWriter(clientOutput,true);
				printWriter.println(str);
				System.out.println("Finish sending to client...");
				
			}
			clientInput.close();
			clientOutput.close();
			socket.close();
			
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		
	}

}

 这段代码主要作用：

   1从构造函数中获得客户端的套接字请求，创建向客户端输入和输出的流。调用线程执行接下来的请求(this.start());

public ServerThread(Socket socket){
			this.socket=socket;
		try {
			this.clientInput=socket.getInputStream();
			this.clientOutput=socket.getOutputStream();
		} catch (IOException e) {
			e.printStackTrace();
		}
		this.start();
	}

   2通过bufferedReader获取客户端的输入并进行分析，假如是over，则向客户端输出over,并关闭，反之。则计算从客户端传来的数值，对应正方形的面积，并蒋结果返回到客户端。之后关闭。

if("over".equalsIgnoreCase(strLine)){
				PrintWriter printWriter=new PrintWriter(clientOutput,true);
				printWriter.println("over");
			}else{
				double side=Double.parseDouble(strLine);
				side=Double.parseDouble(strLine);
				System.out.println("Side of Square Received:"+side);
				double squareArea=side*side;
				String str="Side:"+side+"Square:"+squareArea;
				PrintWriter printWriter=new PrintWriter(clientOutput,true);
				printWriter.println(str);
				System.out.println("Finish sending to client...");
				
			}

注意PrintWriter的使用。。。。。。。。。

下面是客户端调用的代码：

package com.socket.test;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.net.Socket;
import java.net.UnknownHostException;

public class Client {

	public static void main(String[] args) {
		try {
			System.out.println("开始发送请求。。。。");
			Socket socket=new Socket("127.0.0.1",3333);
			BufferedReader bfReader=new BufferedReader(new InputStreamReader(System.in));
			System.out.println("Please input the line.....");
			String strLine=bfReader.readLine();
			
			OutputStream outputStream=socket.getOutputStream();
			InputStream  inputStream=socket.getInputStream();
			
			PrintWriter pw=new PrintWriter(outputStream,true);
			pw.println(strLine);
			BufferedReader br=new BufferedReader(new InputStreamReader(inputStream));
			System.out.println(br.readLine());
			socket.close();
			
		} catch (UnknownHostException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}

}

 代码分析：

Socket socket=new Socket("127.0.0.1",3333);
			BufferedReader bfReader=new BufferedReader(new InputStreamReader(System.in));
			System.out.println("Please input the line.....");
			String strLine=bfReader.readLine();

 建立与服务器的连接：

Socket socket=new Socket("127.0.0.1",3333);

构建缓从输入流：

BufferedReader bfReader=new BufferedReader(new InputStreamReader(System.in));
			System.out.println("Please input the line.....");
			String strLine=bfReader.readLine();

获得服务器的输出和输入流：

OutputStream outputStream=socket.getOutputStream();
			InputStream  inputStream=socket.getInputStream();

把输入发送到服务器：

PrintWriter pw=new PrintWriter(outputStream,true);
			pw.println(strLine);

获得服务器的输出：

BufferedReader br=new BufferedReader(new InputStreamReader(inputStream));
			System.out.println(br.readLine());

这里的

PrintWriter pw=new PrintWriter(outputStream,true);
			pw.println(strLine);

代码用outputStream我理解的是服务器的输出流对应的就是客户端的输入流，所以客户端发送到服务器端的数据就用outputStream,而获取服务器的输出则用inputStream，感觉这有点怪。不敢肯定是否对？

参考java API:

public class PrintWriter

向文本输出流打印对象的格式化表示形式。此类实现在 PrintStream 中的所有 print 方法。它不包含用于写入原始字节的方法，对于这些字节，程序应该使用未编码的字节流进行写入