public class SocketTCP04Server {
    public static void main(String[] args) throws IOException {
        ServerSocket serverSocket =new ServerSocket(9999);
        System.out.println("Server："+serverSocket.getClass());
        System.out.println("正在等待用户连接...");

        //当有用户连接时，会返回一个socket对象
        Socket socket = serverSocket.accept();
        System.out.println("Client："+serverSocket.getClass());//查看连接到的用户

        //接受Client的输入信息
        String read =null;
        InputStream inputStream = socket.getInputStream();
        BufferedReader bufferedReader =new BufferedReader(new InputStreamReader(inputStream));
        while ((read= bufferedReader.readLine())!=null){
            System.out.println(read);
        }
//        String s = bufferedReader.readLine();
//        System.out.println(s);
//        socket.shutdownInput();

        //现在向Client发送数据
        OutputStream outputStream = socket.getOutputStream();
        BufferedWriter bufferedWriter =new BufferedWriter(new OutputStreamWriter(outputStream));
        bufferedWriter.write("Hello, Client 字符流");
        bufferedWriter.newLine();//插入换行符，表示回复内容的结束
        bufferedWriter.flush();
        System.out.println("服务器已关闭~");

        bufferedWriter.close();
        bufferedReader.close();
        socket.close();
        serverSocket.close();

    }
}

public class SocketTCP04Client {
    public static void main(String[] args) throws IOException {
        Socket socket = new Socket(InetAddress.getLocalHost(), 9999);
        System.out.println("获取的Client的socket：" + socket.getClass());

        //现在向Server发送信息
        OutputStream outputStream = socket.getOutputStream();
        BufferedWriter bufferedWriter = new BufferedWriter(new OutputStreamWriter(outputStream));
        bufferedWriter.write("Hello,server 字符流");
        bufferedWriter.newLine();
        /**插入换行符后,相当于写入结束，就不用socket.shutdownOutput();
        此时对面一定要使用readLine()一次读一行代表读取结束*/
        bufferedWriter.flush();

        //现在接受Server的信息
        InputStream inputStream = socket.getInputStream();
        BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
        String read = null;
        while ((read = bufferedReader.readLine()) != null) {
            System.out.println(read);
        }
//        String s = bufferedReader.readLine();
//        System.out.println(s);

        socket.shutdownInput();
        bufferedReader.close();
        bufferedWriter.close();
        socket.close();

    }
}

 

 

此时的服务器还在等待输入，客户端也在等待服务器的应答，产生死锁，僵持不下。

经过一番尝试后发现，

当使用单行读取的时候，使用bufferedWriter.newLine();此时就不用关闭socket的输出流，即socket.shutdownOutput();可以省略，当然写上去也没错。

当使用多行读取的时候，此时，必须使用关闭socket的输出流，即socket.shutdownOutput();不能省略！！！

单行接受代码如下： 

这是Client： 

 //现在向Server发送信息
        OutputStream outputStream = socket.getOutputStream();
        BufferedWriter bufferedWriter = new BufferedWriter(new OutputStreamWriter(outputStream));
        bufferedWriter.write("Hello,server 字符流");
        bufferedWriter.newLine();
        /**插入换行符后,相当于写入结束，就不用socket.shutdownOutput();
        此时对面一定要使用readLine()一次读一行代表读取结束*/
        bufferedWriter.flush();
        socket.shutdownOutput();//可以省略，加上不为错

这是Server端： 

//接受Client的输入信息
        String read =null;
        InputStream inputStream = socket.getInputStream();
        BufferedReader bufferedReader =new BufferedReader(new InputStreamReader(inputStream));
        String s = bufferedReader.readLine();
        System.out.println(s);
        socket.shutdownInput();

多行读取时：

这是Client端： 

 //现在向Server发送信息
        OutputStream outputStream = socket.getOutputStream();
        BufferedWriter bufferedWriter = new BufferedWriter(new OutputStreamWriter(outputStream));
        bufferedWriter.write("Hello,server 字符流");
        bufferedWriter.newLine();
        /**插入换行符后,相当于写入结束，就不用socket.shutdownOutput();
        此时对面一定要使用readLine()一次读一行代表读取结束*/
        bufferedWriter.flush();
        socket.shutdownOutput();//一定不能省略

 这是Server端：

       //接受Client的输入信息
        String read =null;
        InputStream inputStream = socket.getInputStream();
        BufferedReader bufferedReader =new BufferedReader(new InputStreamReader(inputStream));
        while ((read= bufferedReader.readLine())!=null){
            System.out.println(read);
        }
        socket.shutdownInput();//不可省