Java_Socket简单通信

这里主要是想说PrintWriter的write方法和println的区别  我被坑了2小时 

一开始使用的是write和flush方法 我看了看源码  write方法是不会刷新缓存的 使用flush方法 即可刷新缓存  但是此种组合在服务端像输出流写是没有问题的

                             但是如果在客户端 使用write和flush的组合  居然不起作用  效果就是客户端和服务器都在读取那里阻塞 还没找到原因 所以在客户端改为了println方法

其实println方法 就是调用了print和println两个方法 最终调用了newline方法  输出行标示符 和刷新缓存

 private void newLine() {try {    synchronized (lock) {ensureOpen();out.write(lineSeparator);if (autoFlush)    out.flush();    }}

看到这 那么手动输出换行是不是也是可以啊  所以可以使用

writer.write(str);

writer.write("\n");

write.flush();         和 writer.println(str);   方法是等效的

服务端

package com.undergrowth.reactor;import java.io.IOException;import java.net.ServerSocket;import java.net.Socket;import java.net.SocketAddress;public class SocketServerUnder implements Runnable{private ServerSocket serverSocket;public SocketServerUnder(SocketAddress address) throws IOException{serverSocket=new ServerSocket();serverSocket.bind(address);}public Socket getSocket() throws IOException{System.out.println("等待客户端连接");return serverSocket.accept();}@Overridepublic void run() {// TODO Auto-generated method stubwhile(true){try {Socket socket=getSocket();System.out.println("客户端已连接");//System.out.println(socket.getLocalAddress().getHostAddress()+"\t"+socket.getLocalPort());new SocketServerHandler(socket);} catch (IOException e) {// TODO Auto-generated catch blocke.printStackTrace();}}}}

服务端处理

package com.undergrowth.reactor;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 SocketServerHandler extends Thread {private Socket socket;public SocketServerHandler(Socket socket) {// TODO Auto-generated constructor stubthis.socket = socket;this.start();}@Overridepublic void run() {// TODO Auto-generated method stubtry {dealInputStream(socket);dealOutputStream(socket);close(socket);} catch (IOException e) {// TODO Auto-generated catch blocke.printStackTrace();}}/** * 会写给客户端的信息 *  * @param socket2 * @throws IOException */private void dealOutputStream(Socket socket2) throws IOException {// TODO Auto-generated method stubSystem.out.println("处理服务器端回写客户端的消息");OutputStream osOutputStream = socket2.getOutputStream();if (osOutputStream != null) {PrintWriter writer = new PrintWriter(osOutputStream, true);// 如果使用write方法 需要调用flush方法 但是有时不起作用 客户端和服务器端还是无法接受到消息的内容// 还是使用printlnwriter.println("服务器已收到客户端信息");writer.flush();} else {throw new IOException("获取服务端的输出流为空");}}private void dealInputStream(Socket socket) throws IOException {System.out.println("处理服务器端读取客户端的消息");InputStream inputStream = socket.getInputStream();// System.out.println(inputStream);if (inputStream != null) {// 读完客户端发送的数据 将数据会写给客户端BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));String s;// while(true){s = reader.readLine();// if(s!=null&&s.equals("结束")) break;// if(s!=null) System.out.println(s);System.out.println(s);}System.out.println("结束服务器端读取客户端信息");} else {throw new IOException("获取服务端的输入流为空");}}private void close(Socket socket) throws IOException {if (!socket.isClosed()) {System.out.println("处理客户端关闭服务端的连接");if (!socket.isClosed() && !socket.isInputShutdown())socket.getInputStream().close();if (!socket.isClosed() && !socket.isOutputShutdown())socket.getOutputStream().close();if (!socket.isClosed())socket.close();}}}

客户端

package com.undergrowth.reactor;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.InetAddress;import java.net.Socket;public class SocketClientUnder {private Socket socket;public Socket getSocket() {return socket;}public SocketClientUnder(String ip,int port) throws IOException{socket=new Socket(InetAddress.getLocalHost(), 6666);}public InputStream getInputStream() throws IOException{return socket.getInputStream();}public OutputStream getOutputStream() throws IOException{return socket.getOutputStream();}public void write(String str) throws IOException{System.out.println("处理客户端回写服务端的消息");OutputStream osOutputStream=getOutputStream();if(osOutputStream!=null){PrintWriter writer=new PrintWriter(osOutputStream,true);//如果使用write方法 需要调用flush方法  但是有时不起作用 客户端和服务器端还是无法接受到消息的内容//还是使用printlnwriter.println(str);writer.flush();System.out.println("写完客户端回写服务端的消息");}else {throw new IOException("获取客户端的输出流为空");}}public void read() throws IOException {System.out.println("处理客户端读取服务端的消息");InputStream inputStream=getInputStream();if(inputStream!=null){//读完客户端发送的数据 将数据会写给客户端BufferedReader reader=new BufferedReader(new InputStreamReader(inputStream));String s;//while(true){s=reader.readLine();//if(s!=null&&s.equals("结束")) break;//if(s!=null) System.out.println(s);System.out.println(s);//}System.out.println("结束客户器端读取服务端信息");}else {throw new IOException("获取客户端的输入流为空");}}public void close() throws IOException{if(!socket.isClosed()){System.out.println("处理客户端关闭服务端的连接");if(!socket.isClosed()&&!socket.isInputShutdown()) socket.getInputStream().close();if(!socket.isClosed()&&!socket.isOutputShutdown()) socket.getOutputStream().close();if(!socket.isClosed()) socket.close();}}}

测试代码

package com.undergrowth.reactor;import java.io.IOException;import java.net.InetAddress;import java.net.InetSocketAddress;import java.net.SocketAddress;public class SocketTest {/** * @param args * @throws IOException  */public static void main(String[] args) throws IOException {// TODO Auto-generated method stubSocketAddress address=new InetSocketAddress(InetAddress.getLocalHost(), 6666);SocketServerUnder serverUnder=new SocketServerUnder(address);//服务器端等待new Thread(serverUnder).start();//System.out.println(InetAddress.getLocalHost().getHostAddress());//客户端连接SocketClientUnder socketClient=new SocketClientUnder(InetAddress.getLocalHost().getHostAddress(),6666);//System.out.println("客户端连接");//socketClient.getSocket().connect(address);//System.out.println("客户端连接");//for(int i=0;i<10;i++)socketClient.write("来自客户端的信息");//socketClient.write("来自客户端的信息2");//socketClient.write("结束");socketClient.read();socketClient.close();}}