Java网络学习
TCP C/S连接
客户端
-
连接服务器 Socket
-
发送消息
package com.Internetlearn.TCP.interactive; import java.io.IOException; import java.io.OutputStream; import java.net.InetAddress; import java.net.Socket; public class ClientTCP { public static void main(String[] args) { Socket socket = null; OutputStream os = null; try { //要知道服务器地址 端口号 InetAddress serverIP = InetAddress.getByName("127.0.0.1"); int port = 9990; //创建一个socket连接 socket = new Socket(serverIP,port); //发送消息 IO流 os = socket.getOutputStream(); os.write("发送消息".getBytes()); } catch (Exception e) { e.printStackTrace(); }finally { try { os.close(); socket.close(); } catch (IOException e) { e.printStackTrace(); } } } }
服务器端
-
建立服务器的端口ServerSocket
-
等待用户的连接 accept
-
接受用户的消息
package com.Internetlearn.TCP.interactive; import java.io.ByteArrayOutputStream; import java.io.IOException; import java.io.InputStream; import java.net.ServerSocket; import java.net.Socket; public class ServerTCP { public static void main(String[] args) { ServerSocket serverSocket = null; Socket socket = null; InputStream is = null; ByteArrayOutputStream baos = null; try { //我有一个地址 serverSocket = new ServerSocket(9990); //等待客户端连接 socket = serverSocket.accept(); //读取客户端消息 is = socket.getInputStream(); /* 暴力读取 byte[] buffer = new byte[1024]; int len; while((len = is.read(buffer))!=-1){ String message = new String(buffer,0,len); System.out.println(message); } */ //管道流 baos = new ByteArrayOutputStream(); byte[] buffer = new byte[1024]; int len; while(-1 != (len = is.read(buffer))){ baos.write(buffer,0,len); } System.out.println(baos.toString()); } catch (IOException e) { e.printStackTrace(); } finally { try { baos.close(); is.close(); socket.close(); serverSocket.close(); } catch (IOException e) { e.printStackTrace(); } } } }
注意点
一端退出，但退出时并未关闭该连接，另一端如果在从连接中读数据则抛出该异常（Connection reset）。简单的说就是在连接断开后的读和写操作引起的。
TCP 文件上传
服务器端
package com.Internetlearn.TCP.File;
import java.io.*;
import java.net.ServerSocket;
import java.net.Socket;
public class FileServer {
public static void main(String[] args) {
ServerSocket serverSocket = null;
Socket socket = null;
InputStream is = null;
FileOutputStream fos = null;
OutputStream os = null;
try {
//创建服务
serverSocket = new ServerSocket(9000);
//监听客户端的连接
socket = serverSocket.accept();
//获取输入流
is = socket.getInputStream();
//文件输出流
fos = new FileOutputStream(new File("receive.txt"));
byte[] buffer = new byte[1024];
int len;
while(-1!=(len = is.read(buffer))){
fos.write(buffer,0,len);
}
//通知客户端接收完毕
os = socket.getOutputStream();
os.write("接收完毕".getBytes());
} catch (IOException e) {
e.printStackTrace();
} finally {
//
try{
os.close();
fos.close();
is.close();
socket.close();
serverSocket.close();
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
客户端
package com.Internetlearn.TCP.File;
import java.io.*;
import java.net.InetAddress;
import java.net.Socket;
public class FileClient {
public static void main(String[] args) {
Socket socket = null;
OutputStream os = null;
FileInputStream fis = null;
InputStream is = null;
ByteArrayOutputStream baos = null;
try {
//创建Socket连接
socket = new Socket(InetAddress.getByName("127.0.0.1"), 9000);
//创建输出流
os = socket.getOutputStream();
//文件流
fis = new FileInputStream(new File("hamlet.txt"));
//读文件
byte[] inbuffer = new byte[1024];
int inlen;
while ((inlen=fis.read(inbuffer))!=-1){
os.write(inbuffer,0,inlen);
}
//通知服务器我已经发送完了
socket.shutdownOutput();
//确认服务器端接收完毕
is = socket.getInputStream();
baos = new ByteArrayOutputStream();
byte[] outbuffer = new byte[1024];
int outlen;
while((outlen = is.read(outbuffer))!=-1){
baos.write(outbuffer,0,outlen);
}
System.out.println(baos.toString());
} catch (IOException e) {
e.printStackTrace();
} finally {
//关闭资源
try {
baos.close();
is.close();
fis.close();
os.close();
socket.close();
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
UDP
不需要连接，需要知道对方地址
发送端
package com.Internetlearn.UDP;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.net.SocketException;
import java.nio.file.LinkPermission;
//不需要连接服务器
public class UDPClient {
public static void main(String[] args) {
DatagramSocket datagramSocket = null;
try {
//建立一个socket
datagramSocket = new DatagramSocket();
//建个包
String message = "你好！";
//发送给谁 IP + 端口
InetAddress inetAddress = InetAddress.getByName("127.0.0.1");
int port = 9090;
//数据 数据初始位置 数据长度 发送给谁 （IP + 端口）
DatagramPacket datagramPacket = new DatagramPacket(message.getBytes(),0,message.getBytes().length,inetAddress,port);
//发送包
datagramSocket.send(datagramPacket);
} catch (Exception e) {
e.printStackTrace();
} finally {
datagramSocket.close();
}
}
}
接收端
package com.Internetlearn.UDP;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
public class UDPServer {
public static void main(String[] args) {
DatagramSocket datagramSocket = null;
try {
//开放端口（端口号）
datagramSocket = new DatagramSocket(9090);
//创建接收数据包
byte[] buffer = new byte[1024];
DatagramPacket datagramPacket = new DatagramPacket(buffer, 0, buffer.length);
//接收包
datagramSocket.receive(datagramPacket);
//数据显示
System.out.println(new String(datagramPacket.getData(), 0, datagramPacket.getLength()));
} catch (Exception e) {
e.printStackTrace();
} finally {
datagramSocket.close();
}
}
}
在线交互
发送端线程
package com.Internetlearn.UDP.Chat;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.*;
public class TalkSend implements Runnable {
/**
* When an object implementing interface {@code Runnable} is used
* to create a thread, starting the thread causes the object's
* {@code run} method to be called in that separately executing
* thread.
*
* The general contract of the method {@code run} is that it may
* take any action whatsoever.
*
* @see Thread#run()
*/
DatagramSocket datagramSocket = null;
BufferedReader bufferedReader = null;
private int fromPort;//自身端口
private String toIP; //目标IP
private int toPort; //目标端口
public TalkSend(int fromPort, String toIP, int toPort) {
this.fromPort = fromPort;
this.toIP = toIP;
this.toPort = toPort;
try {
datagramSocket = new DatagramSocket(fromPort);
//控制台获取message
bufferedReader = new BufferedReader(new InputStreamReader(System.in));
} catch (SocketException e) {
e.printStackTrace();
}
}
@Override
public void run() {
while(true){
try {
String message = bufferedReader.readLine();
DatagramPacket datagramPacket = new DatagramPacket(message.getBytes(),
0,message.getBytes().length,new InetSocketAddress(this.toIP,this.toPort));
datagramSocket.send(datagramPacket);
//通话结束标志
if("bye".equals(message)){
break;
}
} catch (Exception e) {
e.printStackTrace();
} finally {
datagramSocket.close();
}
}
}
}
接收端线程
package com.Internetlearn.UDP.Chat;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.SocketException;
public class TalkReceive implements Runnable {
/**
* When an object implementing interface {@code Runnable} is used
* to create a thread, starting the thread causes the object's
* {@code run} method to be called in that separately executing
* thread.
*
* The general contract of the method {@code run} is that it may
* take any action whatsoever.
*
* @see Thread#run()
*/
DatagramSocket datagramSocket = null;
private int port;
public TalkReceive(int port) {
this.port = port;
try {
datagramSocket = new DatagramSocket(port);
} catch (Exception e) {
e.printStackTrace();
}
}
@Override
public void run() {
while (true){
try {
//创建接收数据包
byte[] buffer = new byte[1024];
DatagramPacket datagramPacket = new DatagramPacket(buffer, 0, buffer.length);
//接收包
datagramSocket.receive(datagramPacket);
//数据显示
String message = new String(datagramPacket.getData(), 0, datagramPacket.getLength());
System.out.println(message);
//通话结束标志
if("bye".equals(message)){
break;
}
} catch (Exception e) {
e.printStackTrace();
} finally {
datagramSocket.close();
}
}
}
}