迅速摆脱困境

Question

I have a try-catch block as defined below and a for-each loop inside it.

try
{

 // Doing some JDBC Connections here

  Map<String,Connection> connections = new HashMap<>();

   while(DeviceRS.next()){
   final String ip_address = DeviceRS.getString("Connection_vch");
       System.out.println("Value of the IP Address Field:"+ip_address);
   connections.put(ip_address,DriverManager.getConnection("jdbc:mysql://" + ip_address + ":3306/test",RemoteUser,RemotePass));
   }    

    for(final String ip : connections.keySet())
    {

      // Selecting and inserting into database here ...

     }// ENd of for loop

}// ENd of try block
catch(SQLException ex){

ex.printStackTrace();

}

So, if something goes wrong with the connection, my program will get stuck in the catch block,printing the stack trace. I want to move onto other connections.

Is there a way can exit the catch block quickly just after printing the stack trace?

Note: I haven't mentioned full code here as I think my question is not concerned with my code.

Answer 1

Changed your code like this. To quickly skip it on its failure.

 // Doing some JDBC Connections here





       Map<String,Connection> connections = new HashMap<>();
        try
        {

           while(DeviceRS.next()){
           try{
           final String ip_address = DeviceRS.getString("Connection_vch");
           connections.put(ip_address,DriverManager.getConnection("jdbc:mysql://" + ip_address + ":3306/test",RemoteUser,RemotePass));
            }
            catch(SQLException ex){
            ex.printStackTrace();

             }
           }  
    catch(Exception ex){

        ex.printStackTrace();
            System.out.println("in catch block");
//System.exit(0); // dont use this -in real time projects
        }finally{
       System.out.println("in finally block");

        } 

            for(final String ip : connections.keySet())
            {

              // Selecting and inserting into database here ...

             }// ENd of for loop

        }// ENd of try block

Answer 2

I don't think there's fine looking way. But you can make another try-catch block inside your try-catch

 try {
     // your code here

     for(final String ip : connections.keySet()) {
         try { // inner catch
             // your code, that will be continued if sql exception occurs
         } catch (SQLException e) {
             e.printStackTrace();
         }
     }

 } catch (SQLException e) {
     e.printStackTrace();
 }

Answer 3

Like you said if you want if something goes wrong with the connection and you want to move onto another connection,just do this :

 boolean check = true;

 while(check) {
   try {

   Map<String,Connection> connections = new HashMap<>();

   while(DeviceRS.next()){

   final String ip_address = DeviceRS.getString("Connection_vch");
   connections.put(ip_address,DriverManager.getConnection("jdbc:mysql://" + ip_address   +    ":3306/test",RemoteUser,RemotePass));

  } // Ends inner while    

  check = false;  //As connection is ok,we don't need to loop back.  

   for(final String ip : connections.keySet())
   {

     // Selecting and inserting into database here ...
   }

 }// Ends try block

 catch(SQLException ex){

    ex.printStackTrace();

   } //Ends catch block

  finally{

         // close the connection if needed.
   } // Ends finally block

}// Ends outer while loop