java socket实现信息传输

在Java中，可以使用Socket类来实现网络传输。下面是一个简单的示例代码，演示如何使用Socket实现信息传输：

1. 服务端代码：

import java.net.*;
import java.io.*;

public class Server {
    public static void main(String[] args) throws IOException {
        ServerSocket serverSocket = null;
        try {
            serverSocket = new ServerSocket(8888);
        } catch (IOException e) {
            System.err.println("Could not listen on port: 8888.");
            System.exit(1);
        }

        Socket clientSocket = null;
        try {
            clientSocket = serverSocket.accept();
        } catch (IOException e) {
            System.err.println("Accept failed.");
            System.exit(1);
        }

        PrintWriter out = new PrintWriter(clientSocket.getOutputStream(), true);
        BufferedReader in = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));

        String inputLine;

        while ((inputLine = in.readLine()) != null) {
            out.println(inputLine);
        }

        out.close();
        in.close();
        clientSocket.close();
        serverSocket.close();
    }
}

2. 客户端代码：

import java.net.*;
import java.io.*;

public class Client {
    public static void main(String[] args) throws IOException {

        Socket socket = null;
        PrintWriter out = null;
        BufferedReader in = null;

        try {
            socket = new Socket("localhost", 8888);
            out = new PrintWriter(socket.getOutputStream(), true);
            in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
        } catch (UnknownHostException e) {
            System.err.println("Don't know about host: localhost.");
            System.exit(1);
        } catch (IOException e) {
            System.err.println("Couldn't get I/O for the connection to: localhost.");
            System.exit(1);
        }

        BufferedReader stdIn = new BufferedReader(new InputStreamReader(System.in));
        String userInput;

        while ((userInput = stdIn.readLine()) != null) {
            out.println(userInput);
            System.out.println("echo: " + in.readLine());
        }

        out.close();
        in.close();
        stdIn.close();
        socket.close();
    }
}

在这个示例中，服务端监听8888端口，客户端连接到服务端，然后发送消息并接收回复。需要注意的是，这个示例只能发送一行消息，如果需要发送多行消息，需要自行添加分隔符。