线程“main”java.net.BindException中的绑定服务器套接字异常：地址已在使用：JVM_Bind java [重复]

Question

我正在尝试创建一个 Java 程序来从客户端向服务器发送消息并使用套接字编程接收响应，但它出现了这个错误：

线程“main”java.net.BindException 中的异常：地址已在使用中：JVM_Bind 在 java.net.DualStackPlainSocketImpl.bind0（本机方法） 在 java.net.DualStackPlainSocketImpl.socketBind(DualStackPlainSocketImpl.java:106) 在 java.net.AbstractPlainSocketImpl.bind(AbstractPlainSocketImpl.java:387) 在 java.net.PlainSocketImpl.bind(PlainSocketImpl.java:190) 在 java.net.ServerSocket.bind(ServerSocket.java:375) 在 java.net.ServerSocket.(ServerSocket.java:237) 在 java.net.ServerSocket.(ServerSocket.java:128) 在 Bob.main(Bob.java:9)

客户端：

public static void main(String[] args) throws IOException {

    InetAddress addr = InetAddress.getByName("127.0.0.1") ; //set the address of the server to be connected to. Any IP address can be set here as a string
    //If the name is saved in your "etc/hosts" file, then the name can be used instead of the ip address
    //Alternative method: InetAddress.getByAddress -see "stackoverflow" explanation if interested

    System.out.println("addr = " + addr);

    Socket socket = new Socket(addr, 8080); //attempt to connect to the server by creating a socket using the IP address and Port number of the server

    try {
        System.out.println("socket = " + socket);
        BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream())); //create an input variable for the socket- accepts input from the socket

        PrintWriter out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(socket.getOutputStream())),true); // create an output variable for the socket- writes output to the socket

        //this loop simply writes to the socket 10 times waits for a reply from the socket and then prints the reply received
        for(int i = 0; i < 10; i ++) {
            out.println("I am it: " + i); //write to socket
            String str = in.readLine(); //read from socket
            System.out.println(str);    //print to console line read from socket
        }

        out.println("END"); //send string that indicates end of transmission

    }catch( SocketException e ) {
        System.out.println("Server closed connection");
    }finally{
        System.out.println("closing...");
        socket.close(); //close the connection
    }
}

服务器端：

    public static final int PORT = 8080;
    public static void main(String[] args) throws IOException {

    ServerSocket s = new ServerSocket(PORT); //create server socket object
    System.out.println("Started: " + s);

    try {
        Socket socket = s.accept(); //accept a socket connection using the Server Socket created previously
        try {
            System.out.println("Connection accepted: "+ socket);

            BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream())); //create an input variable for the socket- accepts input from the socket

            PrintWriter out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(socket.getOutputStream())),true);   // create an output variable for the socket- writes output to the socket


            //this loop accepts input from the socket, prints out what it receives anc echoes it back into the socket until it recives the word "END" indicating the end of transmission
            while (true) {
                String str = in.readLine(); //read line from socket
                if (str.equals("END")) break;
                System.out.println("Echoing: " + str);  //print line to console
                out.println("You said: " + str); //echo line read back into socket
            }


        }catch ( SocketException  e ) {
            System.out.println("Client closed connection");
        }finally{               //close the present connection
            System.out.println("closing...");
            socket.close();
        }

    }catch( SocketException e ){
        System.out.println("Server socket closed unexpectedly");
    }finally{               //close the server socket. i.e. stop listening for connections
        s.close();          //without this line, the server would continue waiting for another connection
    }
}

Answer 1

java.net.BindException 表示您正在尝试绑定到已占用的端口。

您的服务器有两个实例正在运行，或者其他一些程序已经在使用端口 8080。