无法从 java 服务器应用程序获得响应

Question

我有下面的代码，这是一个非常基本的服务器。在浏览器中，我输入类似：localhost:6789/xxxx。当应用程序运行时，它确实从客户端读取请求，但随后显示消息 "This site can’t be reached" 并且应用程序抛出异常。回应客户的最佳方式是什么？

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

public class URLConnection {
    public static void main(String[] args)throws IOException {
        String clientSentence;
        ServerSocket welcomeSocket = new ServerSocket(6789);

        while (true) {
         Socket connectionSocket = welcomeSocket.accept();
         BufferedReader inFromClient =
          new BufferedReader(new InputStreamReader(connectionSocket.getInputStream()));
         DataOutputStream outToClient = new DataOutputStream(connectionSocket.getOutputStream());
         clientSentence = inFromClient.readLine();
         System.out.println("Received: " + clientSentence);
         outToClient.writeBytes("HTTP/1.1 200 OK");
        }
    }

}

Answer 1

您必须关闭 OutputStream：

    while (true) {
        Socket connectionSocket = welcomeSocket.accept();
        BufferedReader inFromClient =
                new BufferedReader(new InputStreamReader(connectionSocket.getInputStream()));
        DataOutputStream outToClient = new DataOutputStream(connectionSocket.getOutputStream());
        clientSentence = inFromClient.readLine();
        System.out.println("Received: " + clientSentence);
        outToClient.writeBytes("HTTP/1.1 200 OK");
        outToClient.close();
    }

Answer 2

请注意

请求不一定是 HTTP 1.1，因此您的响应无效。

实际上会有几个clientSentence（即考虑如下添加一个循环）

while (true) {
    Socket connectionSocket = welcomeSocket.accept();
    BufferedReader inFromClient =
            new BufferedReader(new InputStreamReader(connectionSocket.getInputStream()));
    DataOutputStream outToClient = new DataOutputStream(connectionSocket.getOutputStream());

    while(true) {
        clientSentence = inFromClient.readLine();
        if (clientSentence != null && clientSentence.trim().isEmpty()) {
            break;
        } else {
            System.out.println("Received: " + clientSentence);
        }
    }

    outToClient.writeBytes("HTTP/1.1 200 OK\n\nHello world");
    outToClient.close();

无法从 java 服务器应用程序获得响应

Cannot get response from java server app

java

http

serversocket