我正在尝试使用Java Server和C Client实现TCP协议。从客户端读取第一个输入时，代码可以正常正常工作。但是，从客户端的第二次输入开始，即使我尝试使用line = line.replaceAll（“ \ s”，“”）删除空格，服务器也会读取“ hi”或“ command1”。这些不是空格吗？是否有从C读取到Java的垃圾？现在，在我发送第二条命令之后，该程序被阻止，因为服务器无法识别带有这些空格的命令，也无法将任何内容发送回客户端。非常感谢您的帮助或建议，谢谢您的宝贵时间。

以下是我的Java服务器代码：

// A Java program for a Server 
import java.net.*; 
import java.io.*; 

public class HXServerJava 
{ 
    //initialize socket and input stream 
    private Socket          socket   = null; 
    private ServerSocket    server   = null; 
    private DataInputStream in       =  null; 

    // constructor with port 
    public HXServerJava(int port) 
    { 
        // starts server and waits for a connection 
        try
        { 
            server = new ServerSocket(port); 
            System.out.println("Server started"); 

            System.out.println("Waiting for a client ..."); 

            socket = server.accept(); 
            System.out.println("Client accepted"); 

            // takes input from the client socket 
            BufferedReader in= new BufferedReader(new InputStreamReader(socket.getInputStream()));
            PrintWriter out=new PrintWriter(socket.getOutputStream(),true);
            String line = ""; 

            // reads message from client until "over" is sent 
            while (!line.equals("over")) 
            { 
                try
                { 
                    line = in.readLine(); 
                    System.out.println("line before is: " + line);
                    line = line.replaceAll("\\s",""); //trying to get rid of whitespace
                    System.out.println("line after is: " + line);
                    if ((line != null && line.equals("hi")==true)) {
                        out.print("Welcome by server\n");
                        out.flush();
                        //out.close();
                    }
                    if ((line != null && line.equals("command1")==true)) {
                        out.print("first command executed\n");
                        out.flush();
                        //out.close();
                    }

                } 
                catch(IOException i) 
                { 
                    System.out.println(i); 
                } 
            } 
            System.out.println("Closing connection"); 
            out.print("exit\n");
            out.flush();
            // close connection 
            socket.close(); 
            in.close(); 
            out.close();
        } 
        catch(IOException i) 
        { 
            System.out.println(i); 
        } 
    } 

    public static void main(String args[]) 
    { 
        HXServerJava server = new HXServerJava(5000); 
    } 
} 

以下是我的C客户端代码：

#include <netdb.h> 
#include <stdio.h> 
#include <stdlib.h> 
#include <string.h> 
#include <unistd.h>
#include <arpa/inet.h>
#include <sys/socket.h> 
#define MAX 80 
#define PORT 5000 
#define SA struct sockaddr 
void func(int sockfd) 
{ 
    char buff[MAX]; 
    int n,m; 
    char *str;
    int exitflag = 0;
    str = malloc(sizeof (char) * MAX);
    while (exitflag != 1){
        bzero(buff,sizeof(buff)); 
        printf("Enter the string : "); 
        n = 0; 
        while ((buff[n++] = getchar()) != '\n') 
            ; 
        //strcpy (str,buff);
        //strcat(str,"\n");
        printf("String is: %s\n",buff);
        m = write(sockfd,buff,sizeof(buff)); 
        if (m < 0){
            perror ("ERROR writing to socket\n");
        }
        bzero(buff,sizeof(buff)); 
        m = read(sockfd,sizeof(buff)); 
        if (n < 0) {
            perror("ERROR reading from socket\n");
        }
        printf("From Server : %s\n",buff); 
        if ((strncmp(buff,"exit",4)) == 0) { 
            exitflag = 1;
            printf("Client Exit...\n"); 
            break; 
        } 
    } 
} 

int main() 
{ 
    int sockfd,connfd; 
    struct sockaddr_in servaddr,cli; 

    // socket create and varification 
    sockfd = socket(AF_INET,SOCK_STREAM,0); 
    if (sockfd == -1) { 
        printf("socket creation failed...\n"); 
        exit(0); 
    } 
    else
        printf("Socket successfully created..\n"); 
    bzero(&servaddr,sizeof(servaddr)); 

    // assign IP,PORT 
    servaddr.sin_family = AF_INET; 
    servaddr.sin_addr.s_addr = inet_addr("127.0.0.1"); 
    servaddr.sin_port = htons(PORT); 

    // connect the client socket to server socket 
    if (connect(sockfd,(SA*)&servaddr,sizeof(servaddr)) != 0) { 
        printf("connection with the server failed...\n"); 
        exit(0); 
    } 
    else
        printf("connected to the server..\n"); 

    // function for chat 
    func(sockfd); 

    // close the socket 
    close(sockfd); 
}