问如何修复:连接到本地主机时出错: Java中的连接被拒绝

EN

import java.net.*;
public class Connect {
   public static void main(String[] args) {
      String server_name = "localhost";

      try {
         Socket sock = new Socket(server_name, 80);

         System.out.println("***Connect to " + server_name + " ***");

         sock.close();

      }

      catch (java.io.IOException e ) {

         System.out.println("Error connect to " + server_name + 
         ": " + e);

         return;
      }
   }
}