java socket的正确关闭姿势

java socket对应的是网络协议中的tcp，tcp的三次握手、四次挥手、11中状态什么的这里就不说了，不知道大家平常使用socket的时候如果不注意的情况下，会不会遇到各种异常报错。
例如：

java.net.SocketException:socket is closed
错误提示的出现场景：
自己主动关闭了socket，但是之后还从里面读写数据

Software caused connection abort: socket write error
错误提示的出现场景：
对方已经关闭socket，依旧向对方写数据

connection reset (by peer)
错误提示出现的场景：
一端socket被关闭，另一端仍然发送数据，发送的第一个数据包 connection reset by peer
一端socket退出，退出时为关闭连接，另一端读数据 connection reset

所以在使用socket时，需要约定好双方读写完成的条件，然后关闭输入输出流：

socket.shutdownInput();
socket.shutdownOutput();

即当一方写入完成后，调用shutdownOutput关闭输出流，这时候对方的read方法就会返回-1，这时候对方就知道你写完了，对方可以关闭输入流，然后等待对方写入完成调用shutdownOutput后己方再调用shutdownInput，双方就正常关闭了输入输出流，这时候socket就不会出现异常了。

下面是一个socket交互的例子：
server端

public class OioServer {
    public static void main(String[] args) throws IOException {
        ServerSocket serverSocket = new ServerSocket(8080);
        while (true) {
            Socket socket = serverSocket.accept();
            System.out.println("socket = " + socket);
            new Thread(() -> {
                try {
                    InputStream in = socket.getInputStream();
                    OutputStream out = socket.getOutputStream();
                    out.write("hello! I get your message that is follow".getBytes(Charset.forName("UTF-8")));
                    byte[] buf = new byte[1024];
                    int len;
                    while ((len = in.read(buf)) != -1) {
                        System.out.print(new String(buf, 0, len, Charset.forName("UTF-8")));
                        out.write(buf, 0, len);
                    }
                    out.write("\n end \n".getBytes(Charset.forName("UTF-8")));
                    out.flush();
                    socket.shutdownInput();
                    socket.shutdownOutput();
                } catch (IOException e) {
                    e.printStackTrace();
                }finally {
                    try {
                        socket.close();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
            }).start();
        }
    }
}

client端

public class OioClient {
    public static void main(String[] args) throws IOException {
        Socket socket = new Socket("127.0.0.1", 8080);
        InputStream in = socket.getInputStream();
        new Thread(() -> {
            BufferedInputStream bufferIn = new BufferedInputStream(in);
            byte[] buf = new byte[1024];
            try {
                int len;
                while ((len = bufferIn.read(buf)) != -1) {
                    System.out.print(new String(buf, 0, len, Charset.forName("UTF-8")));
                }
            }catch (Exception e) {
                e.printStackTrace();
            }
            try {
                socket.shutdownInput();
                socket.close();
            } catch (IOException e) {
                e.printStackTrace();
            }

        }).start();
        OutputStream out = socket.getOutputStream();
        int cout = 10;
        while (cout-- > 0) {
            out.write(("this time is " + System.currentTimeMillis() + "\n").getBytes("UTF-8"));
        }
        socket.shutdownOutput();
    }
}