java實現TCP通訊
阿新 • • 發佈:2020-06-24
1.概述
通過ServerSocket與Socket實現的TCP的通訊,這個例子配合了swing使用,其實作者之前發過一篇ServerSocker與Socket的通訊,在這裡,這邊文章就是在這個例子上修改而成的.
其實原理很簡單的,就是一個服務端一個客戶端,服務端這邊建立好ServerSocket後,使用accept()堵塞一直等待客戶端傳送socket. 好吧,不廢話了.進正題.
2.服務端
swing的部分就不說了,說一下主要操作
(1)新建ServerSocket
ServerSocket serverSocket = null;
serverSocket = new ServerSocket(12345 );//一個不被佔用的埠即可
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構造方法的引數是埠,預設使用本地ip. ServerSocket有三個構造方法,
ServerSocket(int port);
ServerSocket(int port,int backlog);
ServerSocker(int poer,int backlog,InetAddress ip);
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(2)接收socket
Socket socket = serverSocket.accept();
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返回一個Socket(),會一直等待,處於阻塞狀態. 一般設定一個while(true)迴圈接收.
(3)資料處理
使用DataInputStream與DataOutputStream:
DataInputStream inputStream = new DataInputStream(socket.getInputStream());
DataOutputStram outputStream = new DataOutputStream(socket.getOutputStream());
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然後使用read與write方法即可. 注意關閉的時候要等輸入輸出完成後再一起關閉,就是說,不能這樣:
DataInputStream inputStream = new DataInputStream(socket.getInputStream());
String data = inputStream.readUTF();
inputStream.close();
DataOutputStream outputStream = new DataOutputStream(socket.getOutputStream());
outputStream.writeUTF("ok");
outputStream.close();
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這樣的話getInputStream()沒有問題,但是到了getOutputStream()的時候就有問題了,會提示異常:
Socket is closed. 所以解決辦法就是等輸出完之後再一起關閉:DataInputStream inputStream = new DataInputStream(socket.getInputStream());
String data = inputStream.readUTF();
DataOutputStream outputStream = new DataOutputStream(socket.getOutputStream());
outputStream.writeUTF("ok");
inputStream.close();//等輸出完成後再關閉
outputStream.close();
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(4)完整程式碼Server.java
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.net.InetAddress;
import java.net.ServerSocket;
import java.net.Socket;
import javax.swing.*;
public class Server {
public static void main(String[] args)
{
JFrame frame = new JFrame("Server");
JPanel panel = new JPanel();
JTextArea text = new JTextArea();
panel.add(text);
frame.setContentPane(panel);
frame.setSize(600,300);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
ServerSocket serverSocket = null;
try
{
serverSocket = new ServerSocket(12345);
while (true)
{
Socket socket = serverSocket.accept();
DataInputStream inputStream = new DataInputStream(socket.getInputStream());
text.setText(inputStream.readUTF());
DataOutputStream outputStream = new DataOutputStream(socket.getOutputStream());
outputStream.writeUTF("ok");
inputStream.close();
outputStream.close();
socket.close();
}
}
catch (IOException e)
{
e.printStackTrace();
}
finally
{
try
{
serverSocket.close();
}
catch (IOException e)
{
e.printStackTrace();
}
}
}
}
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3.客戶端
客戶端的操作就是開啟一個Socket,再通過這個socket獲取對應的輸入輸出流就可以了.
(1)新建一個Socket
Socket socket = new Socket("127.0.0.1",12345);//這個埠與服務端的埠對應
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Socket有三個構造方法:
Socket(InetAddress ip,int port);
Socket(String ip,int port);
Socket(InetAddress ip,int port,InetAddress localIp,int localPort);
Socket(String ip,int localPort);
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(2)輸入輸出
同樣使用DataInputStream與DataOutputStream:
DataOutputStream outputStream = new DataOutputStream(socket.getOutputStream());
DataInputStream inputStream = new DataInputStream(socket.getInputStream());
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(3)完整程式碼Client.java
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.net.Socket;
import javax.swing.*;
import java.awt.GridLayout;
public class Client
{
public static void main(String[] args) {
JFrame frame = new JFrame();
JTextArea text = new JTextArea();
JButton send = new JButton();
GridLayout layout = new GridLayout(2,1,0,5);
frame.setTitle("Client");
frame.setVisible(true);
frame.setLocationRelativeTo(null);
frame.setSize(600,300);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(layout);
frame.add(text);
frame.add(send);
send.setText("send");
send.addActionListener(v ->
{
try
{
String host = "127.0.0.1";
int port = 12345;
Socket socket = new Socket(host,port);
DataOutputStream outputStream = new DataOutputStream(socket.getOutputStream());
outputStream.writeUTF(text.getText());
DataInputStream inputStream = new DataInputStream(socket.getInputStream());
text.setText(inputStream.readUTF());
outputStream.close();
inputStream.close();
socket.close();
}
catch (IOException e)
{
e.printStackTrace();
}
});
}
}
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4.測試
先開啟服務端,再開啟客戶端,這裡設定了服務端返回給客戶端的資訊為"ok".