Java 如何检测远端插座关闭?
如何检测是否在远程端的套接字上调用了Java 如何检测远端插座关闭?,java,networking,sockets,tcp,Java,Networking,Sockets,Tcp,如何检测是否在远程端的套接字上调用了Socket#close()。isConnected方法没有帮助,即使远程端关闭了套接字,它也会返回true。试试这个: public class MyServer { public static final int PORT = 12345; public static void main(String[] args) throws IOException, InterruptedException { ServerSocke
Socket#close()
。isConnected方法没有帮助,即使远程端关闭了套接字,它也会返回true
。试试这个:
public class MyServer {
public static final int PORT = 12345;
public static void main(String[] args) throws IOException, InterruptedException {
ServerSocket ss = ServerSocketFactory.getDefault().createServerSocket(PORT);
Socket s = ss.accept();
Thread.sleep(5000);
ss.close();
s.close();
}
}
public class MyClient {
public static void main(String[] args) throws IOException, InterruptedException {
Socket s = SocketFactory.getDefault().createSocket("localhost", MyServer.PORT);
System.out.println(" connected: " + s.isConnected());
Thread.sleep(10000);
System.out.println(" connected: " + s.isConnected());
}
}
启动服务器,启动客户端。您将看到它打印“connected:true”两次,即使第二次关闭套接字也是如此
真正找到答案的唯一方法是在相关的输入/输出流上读取(返回值为-1)或写入(抛出
IOException
(断管)。在写入客户端套接字时,还可以检查套接字输出流错误
out.println(output);
if(out.checkError())
{
throw new Exception("Error transmitting data.");
}
由于答案有偏差,我决定对此进行测试并公布结果——包括测试示例 这里的服务器只是将数据写入客户端,不需要任何输入 服务器:
ServerSocket serverSocket = new ServerSocket(4444);
Socket clientSocket = serverSocket.accept();
PrintWriter out = new PrintWriter(clientSocket.getOutputStream(), true);
while (true) {
out.println("output");
if (out.checkError()) System.out.println("ERROR writing data to socket !!!");
System.out.println(clientSocket.isConnected());
System.out.println(clientSocket.getInputStream().read());
// thread sleep ...
// break condition , close sockets and the like ...
}
- clientSocket.isConnected()在客户端连接后(甚至在断开连接后)始终返回true李>
- getInputStream().read()
- 只要客户端连接,线程就会等待输入,因此程序不会执行任何操作,除非您得到一些输入
- 如果客户端断开连接,则返回-1
- 一旦客户端断开连接,out.checkError()就为true,因此我建议这样做