使用线程java的错误TCP客户端服务器聊天程序

Question

我正在制作一个 tcp 客户端服务器聊天程序。我的服务器是线程做的，代码如下：

    System.out.println("Server binded at "+((client.getInetAddress()).getLocalHost()).getHostAddress()+":9867");
    System.out.println("Run the Client");
    //ready to accept client request
    //opening the input stream to read data from client connection
    in= new BufferedReader(new InputStreamReader(client.getInputStream()));
    System.out.println(in.readLine());

                //using output stream responsing data 

                out=new PrintStream(client.getOutputStream());
                out.print("Welcome by server\n");

                System.out.println("1");

                in= new BufferedReader(new InputStreamReader(client.getInputStream()));
    System.out.println(in.readLine());                        


                while(! in.readLine().trim().equals("*")) {

                    //using output stream responsing data 
                    System.out.println("3");
                   BufferedReader bufferRead = new BufferedReader(new InputStreamReader(System.in));
                    str = bufferRead.readLine();                    
                    out.println(str);
                    out.flush();

                    //opening the input stream to read data from client connection
            in= new BufferedReader(new InputStreamReader(client.getInputStream()));
                      System.out.println(in.readLine());

        }

我的客户端文件是：（简单无线程）

client =new Socket("127.0.0.1", 9867);

                System.out.println("Client connected ");
                //getting the o/p stream of that connection
                out=new PrintStream(client.getOutputStream());
                //sending the message to server
                out.print("Hello from client\n");

                //reading the response using input stream
                in= new BufferedReader(new InputStreamReader(client.getInputStream()));
                System.out.println(in.readLine());

                bufferRead = new BufferedReader(new InputStreamReader(System.in));
                str = bufferRead.readLine();                    
                out=new PrintStream(client.getOutputStream());
                out.print(str);
                out.flush();

                while(! in.readLine().trim().equals("*")) {

                   // opening the input stream to read data from server connection
                   in= new BufferedReader(new InputStreamReader(client.getInputStream()));
                    System.out.println("4");
                    System.out.println(in.readLine());
                    System.out.println("5");

                    out=new PrintStream(client.getOutputStream());
                    bufferRead = new BufferedReader(new InputStreamReader(System.in));
                    str = bufferRead.readLine();                    
                    out.print(str);
                    out.flush();

                }

现在对我来说发生了一件奇怪的事情。当我注释掉两个文件上的 while 循环时，程序运行良好。但是当我在向服务器发送消息后取消评论时，我的客户端进入了 while 循环，我的服务器继续等待响应。

所以输出是：（客户端）

Client connected 
Welcome by server
l;skc
4

和服务器是：

Server binded at 192.168.1.242:9867
Run the Client
Hello from client
1

我认为这是由于使用了线程/异步进程。请帮助

修改后的代码

服务器端：

System.out.println("Server binded at "+((client.getInetAddress()).getLocalHost()).getHostAddress()+":9867");
            System.out.println("Run the Client");
            //ready to accept client request
            //opening the input stream to read data from client connection
            in= new BufferedReader(new InputStreamReader(client.getInputStream()));
            System.out.println(in.readLine());

                        //using output stream responsing data 

                        out=new PrintStream(client.getOutputStream());
                        out.print("Welcome by server\n");

                        System.out.println("1");

                        str = in.readLine();
            System.out.println(str);                        


                        while(!str.trim().equals("*")) {

                            //using output stream responsing data 
                            System.out.println("3");
                           BufferedReader bufferRead = new BufferedReader(new InputStreamReader(System.in));
                            str = bufferRead.readLine();                    
                            out.println(str);
                            out.flush();

                            //opening the input stream to read data from client connection
                    in= new BufferedReader(new InputStreamReader(client.getInputStream()));
                              System.out.println(in.readLine());

                }

客户端：

client =new Socket("127.0.0.1", 9867);

            System.out.println("Client connected ");
            //getting the o/p stream of that connection
            out=new PrintStream(client.getOutputStream());
            //sending the message to server
            out.print("Hello from client\n");

            //reading the response using input stream
            in= new BufferedReader(new InputStreamReader(client.getInputStream()));
            System.out.println(in.readLine());

            bufferRead = new BufferedReader(new InputStreamReader(System.in));
            str = bufferRead.readLine();                    
            out=new PrintStream(client.getOutputStream());
            out.print(str);
            out.flush();

            while(! str.trim().equals("*")) {

               // opening the input stream to read data from server connection
                str = in.readLine();
                System.out.println("4");
                System.out.println(str);

                out=new PrintStream(client.getOutputStream());
                str = bufferRead.readLine();                    
                out.print(str);
                out.flush();

            }

Answer 1

对于您的示例，我强烈推荐通过以下链接http://docs.oracle.com/javase/tutorial/networking/sockets/clientServer.html 进行敲击敲门协议

对我来说，代码中明显的主要错误是

   while(! str.trim().equals("*"))

应该是什么时候

while ((str = in.readLine()) != null) {
System.out.println("Server: " + str);

这意味着你的线程将通过输入流持续监听输入，然后你可以在服务器返回响应后对 str 变量做任何你想做的事情

Answer 2

第一条线索。看看你能用这个做什么：

这一行：

 System.out.println(in.readLine());

将从传入连接中读取一行并回显它。当它这样做时，行内容消失了，如果您再次尝试调用“in.readLine()”，它将尝试读取另一行，而不是再次读取同一行。

此外，这一行：

in= new BufferedReader(new InputStreamReader(client.getInputStream()));

通常只会出现一次。当你构建阅读器时，你只需要使用它。您不必一遍又一遍地重建它。