Java socket客户端不停止读取数据

Question

Hello i'm trying to execute a socket client in Java, but the client still reading the data and don't proceed with the program execution. Any ideas?

Here's the code:

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

public class SocketTeste {

    public static void main(String[] args) {
        try {
            Socket client = new Socket("127.0.0.1", 1987);
            System.out.println("Got connection");
            DataInputStream handshake = new DataInputStream(client.getInputStream());
            String handshakePure = handshake.readUTF();
            System.out.println("Got the handshake");
            System.out.println(handshakePure);
            DataOutputStream saida = new DataOutputStream(client.getOutputStream());
            saida.writeUTF("Got it!");
            saida.flush();
            saida.close();
            String returnedData = handshake.readUTF();
            System.out.println(returnedData);
            handshake.close();
            client.close();
        } catch (Exception e) {
            System.out.println("ERROR: " + e);
        }
    }
}

I don't think if that matter, but the socket server is a PHP socket server.

Answer 1

DataInputStream.readUTF expects a uniquely weird message format. The first two bytes it reads are interpreted as the length of the string to read, in a big endian binary format. This is then followed by a weird non-standard text encoding similar to but incompatible with UTF-8. Most likely you should not be using DataInputStream.readUTF to read data in a program, unless you used its counterpart DataOutputStream.writeUTF to write it in the first place.

Based on your comments it sounds like your communication protocol is based on lines of text. To read lines of text, you can use for example the BufferedReader class.

BufferedReader handshake = new BufferedReader(new InputStreamReader(client.getInputStream(), StandardCharsets.UTF_8));
String handshakePure = handshake.readLine();