java-用java.net.Socket和java.net.ServerSocket实现简单的聊天程序

java.net.Socket

java.net.ServerSocket

Server.class

Client.class

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Client.java

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.net.InetAddress;
import java.net.Socket;
import java.net.SocketException;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Date;

/**
* Created by DuanJiaNing on 2017/3/16.
*/
public class Client {

public static void main(String[] args) {
try {
//创建Socket连接到本机的2003端口
Socket socket = new Socket(InetAddress.getLocalHost(), 2003);
println("**********您正在和：" + InetAddress.getLocalHost().getHostAddress() + " 聊天***********\n" + "输入信息，按回车即可发送!输入quit可结束会话并关闭程序。");
OutputStream out = socket.getOutputStream();
out.write("Hello 在么？".getBytes());

//创建新线程负责打印接收到的消息
new Thread(new ClientThread(socket.getInputStream())).start();

//接收控制台输入
BufferedReader bufr = new BufferedReader(new InputStreamReader(System.in));
//读取控制台输入，有输入且不为quit时进行发送
String line;
while ((line = bufr.readLine()) != null && !line.equals("quit")) {
out.write(line.getBytes());
}
//关闭套接字
//程序结束 这将导致ClientThread抛java.net.SocketException: Socket closed异常而结束（暂且就这样关闭这个线程）
socket.close();

} catch (Exception e) {
e.printStackTrace();
}
}

static class ClientThread implements Runnable {
InputStream input;

public ClientThread(InputStream in) {
this.input = in;
}

public void run() {
byte[] bytes = new byte[1024];
int len;
try {
//当收到消息时把消息打印到控制台
while ((len = input.read(bytes)) != -1) {
println(new String(bytes, 0, len));
}
} catch (Exception e) {
//当服务端或客户端结束会话时（输入quit时）会关闭socket从而抛出java.net.SocketException: Socket closed异常
//隐藏此异常不做处理让程序继续“正常”运行(正常结束)
if (!(e instanceof SocketException))
e.printStackTrace();
}
println("**********此次会话结束**********");
System.exit(0);
}
}

private static void println(String msg) {
Date date = new Date();
DateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss ");
System.out.println(format.format(date) + msg);
}

}

Server.java

import java.io.*;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.SocketException;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Date;

/**
* Created by DuanJiaNing on 2017/3/16.
*/
public class Server {

private static BufferedReader reader;

public static void main(String[] args) {

//监听本机（服务器）的2003端口
ServerSocket serverSocket = null;
try {
serverSocket = new ServerSocket(2003);
} catch (IOException e) {
e.printStackTrace();
}
while (true) {

try {
println("************当前没有正在进行的会话***********");

//accept为阻塞时方法，当有连接时会返回连接着的socket对象
Socket socket = serverSocket.accept();
println("当前聊天对象来自：" + socket.getLocalAddress().getHostAddress() + "\n" + "输入信息，按回车即可发送!输入quit可结束此次会话。");

//创建新线程负责打印接收到的消息
InputStream in = socket.getInputStream();
new Thread(new ServerThread(in)).start();

//接收输入并发送给连接者
reader = new BufferedReader(new InputStreamReader(System.in));
String line;
OutputStream out = socket.getOutputStream();
while ((line = reader.readLine()) != null && !line.equals("quit")) {
out.write(line.getBytes());
}
//服务端主动结束会话
out.write("先不聊了。bye~".getBytes());

//关闭套接字
//程序结束 这将导致ServerThread抛java.net.SocketException: Socket closed异常而结束（暂且就这样关闭此次会话对应的线程）
socket.close();

} catch (Exception e) {
//当客户端主动结束会话（输入quit时），而服务端试图发送信息时会抛出java.net.SocketException: Software caused connection abort: socket write error
//借这个异常让服务端回到等待客户端接入状态
if (e instanceof SocketException) {
println("您的聊天对象已离线\n");
continue;
}
else
e.printStackTrace();
}
}
}

static class ServerThread implements Runnable {
InputStream input;

public ServerThread(InputStream in) {
this.input = in;
}

public void run() {
byte[] bytes = new byte[1024];
int len;
try {
//当收到消息时把消息打印到控制台
while ((len = input.read(bytes)) != -1) {
println(new String(bytes, 0, len));
}
} catch (Exception e) {
//当服务端或（输入quit时）会关闭socket从而抛出java.net.SocketException: Socket closed异常
//当服务端输入quit时隐藏此异常不做处理让程序继续运行（回到等待客户端接入的状态）
if (!(e instanceof SocketException)) {
e.printStackTrace();
}
}

}
}

private static void println(String msg) {
Date date = new Date();
DateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss ");
System.out.println(format.format(date) + msg);
}
}

javac Server.java
javac Client.java

java Server
java Client

quit

java Client