为 C++ 服务器实现 Java TCP 客户端

Question

我正在尝试实现 TCP 服务器-客户端应用程序。服务器是用 C++ 编写的，客户端是 Java.

TCP 服务器正在使用 CURL 和 Mozilla 浏览器，但不支持 CHROME 以及 Java 客户端。
客户端脚本能够访问服务器，但无法从服务器消息中检索响应和打印。

Client.java

//client side 
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.MalformedURLException;
import java.net.URL;
import java.io.UnsupportedEncodingException;

public class Client {

    public static void main(String[] args) {

        URL url = null;
        try {
            url = new URL("http://192.168.1.101:12345");
        } catch (MalformedURLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

        BufferedReader reader = null;
        try {
            reader = new BufferedReader(new InputStreamReader(url.openStream(), "UTF-8"));
        } catch (UnsupportedEncodingException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

        try {
            for (String line; (line = reader.readLine()) != null;) {
                System.out.println(line);
            }
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

    }
}

server.cpp


// Server side C/C++ program to demonstrate Socket programming 
#include <unistd.h> 
#include <stdio.h> 
#include <sys/socket.h> 
#include <stdlib.h> 
#include <netinet/in.h> 
#include <string.h> 
#define PORT 12345
int main(int argc, char const *argv[]) 
{ 
    int server_fd, new_socket, valread; 
    struct sockaddr_in address; 
    int opt = 1; 
    int addrlen = sizeof(address); 
    char buffer[1024] = {0}; 
    char *hello = "Hello from server"; 

    // Creating socket file descriptor 
    if ((server_fd = socket(AF_INET, SOCK_STREAM, 0)) == 0) 
    { 
        perror("socket failed"); 
        exit(EXIT_FAILURE); 
    } 

    // Forcefully attaching socket to the port 8080 
    if (setsockopt(server_fd, SOL_SOCKET, SO_REUSEADDR | SO_REUSEPORT, 
                                                &opt, sizeof(opt))) 
    { 
        perror("setsockopt"); 
        exit(EXIT_FAILURE); 
    } 
    address.sin_family = AF_INET; 
    address.sin_addr.s_addr = INADDR_ANY; 
    address.sin_port = htons( PORT ); 

    // Forcefully attaching socket to the port 8080 
    if (bind(server_fd, (struct sockaddr *)&address, 
                                sizeof(address))<0) 
    { 
        perror("bind failed"); 
        exit(EXIT_FAILURE); 
    } 
    if (listen(server_fd, 3) < 0) 
    { 
        perror("listen"); 
        exit(EXIT_FAILURE); 
    } 
    if ((new_socket = accept(server_fd, (struct sockaddr *)&address, 
                    (socklen_t*)&addrlen))<0) 
    { 
        perror("accept"); 
        exit(EXIT_FAILURE); 
    } 
    valread = read( new_socket , buffer, 1024); 
    printf("%s\n",buffer ); 
    send(new_socket , hello , strlen(hello) , 0 ); 
    printf("Hello message sent\n"); 
    return 0; 
}

" 来自服务器的问候未显示在控制台上并且 java 提供错误信息：

java.io.IOException: Invalid Http response
    at sun.net.www.protocol.http.HttpURLConnection.getInputStream0(HttpURLConnection.java:1606)
    at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1492)
    at java.net.URL.openStream(URL.java:1045)
    at com.sri.tcptest.Client.main(Client.java:24)
Exception in thread "main" java.lang.NullPointerException
    at com.srinar.tcptest.Client.main(Client.java:34) "

Answer 1

您的服务器响应无效的 HTTP 响应。

要么让它有效，要么让你的客户端不期望它（使用普通套接字代替哦 HTTP 客户端）。

Answer 2

在 server.cpp 文件中，更改：

char *hello = "HTTP/1.1 200 OK\r\nContent-Length: 17\r\nContent-Type: text/html\r\n\r\nHello from server";

为 C++ 服务器实现 Java TCP 客户端

Implementing Java TCP client for C++ server

c++

java

tcp

client-server