问我使用javaudp去接收硬件设备的数据，但是在judp以后他就立马自动关闭了，请问怎么处理？

@PostConstruct

public String recv() throws Exception {

DatagramSocket ds = new DatagramSocket(20055);

new Thread(() -> {

while (true) {

byte[] buf = new byte[1024];

DatagramPacket dp = new DatagramPacket(buf, buf.length);

try {

System.out.println("准备接收..");

// ds.setSoTimeout(2000);

ds.receive(dp);

} catch (IOException e) {

System.out.println("接收失败..");

e.printStackTrace();

}

String ip = dp.getAddress().getHostAddress();

int port = dp.getPort();

String de = new String(dp.getData(), 0, dp.getLength());

if (de.equals("exit")) {

System.out.println(ip + "退出会话.....");

break;

}

System.out.println(ip + ":" + port + "===>" + de);

Gson gson = new Gson();

String jsonStr = gson.toJson(de);

//每次得到数据存数据库或缓存

System.out.println("接收数据；" + jsonStr);

}

}).start();

//关闭资源

ds.close();

return null;

}

public void action() {

System.out.println("bean has been init.");

}

}

错误信息：

准备接收..

接收失败..

java.net.SocketException: Socket closed

at java.net.DualStackPlainDatagramSocketImpl.checkAndReturnNativeFD(DualStackPlainDatagramSocketImpl.java:260)

at java.net.DualStackPlainDatagramSocketImpl.receive0(DualStackPlainDatagramSocketImpl.java:117)

at java.net.AbstractPlainDatagramSocketImpl.receive(AbstractPlainDatagramSocketImpl.java:143)

at java.net.DatagramSocket.receive(DatagramSocket.java:812)

at com.zukai.connectionudp.UdpReceive.lambda$0(UdpReceive.java:71)

at java.lang.Thread.run(Thread.java:748)

Exception in thread "Thread-1" java.lang.NullPointerException

at com.zukai.connectionudp.UdpReceive.lambda$0(UdpReceive.java:76)

at java.lang.Thread.run(Thread.java:748)