I'm new to java but I'm picking it up pretty quickly. One thing that I keep running into is I end up having one function that is full of queries and just code in general and I would like to break it down into separate functions. Take this for example:
public ResultSet getApples (){
ResultSet rs;
try{
PreparedStatement stmt = con.prepareStatement("SELECT * FROM fruit WHERE type='apples'");
rs = stmt.executeQuery();
} catch (SQLException e){
e.printStackTrace();
}
return rs;
}
Ideally this would be what I want to do, have all of try's and catches within one function, but this gives me the error: Local variable may not have been initilized
I do realize I could do this:
public function start(){
try{
ResultSet apples = getApples();
catch (SQLException e){
e.printStackTrace();
}
}
public ResultSet getApples () throws SQLException {
PreparedStatement stmt = con.prepareStatement("SELECT * FROM fruit WHERE type='apples'");
return stmt.executeQuery();
}
But I would really rather have the exceptions handled within the function as well as it return a result.
EDIT
Alright so kinda a modififed answer to whats being provided. My whole goal on this question was to make the main functions of my script as clean as possible. Even the extra if ( _resultSet != null )
was something that I didn't really like. That being said I am pretty happy with this result:
public ResultSet getApples (){
try{
PreparedStatement stmt = con.prepareStatement("SELECT * FROM fruit WHERE type='apples'");
return stmt.executeQuery();
} catch (SQLException e){
System.out.println("************************");
System.out.println("Class.getApples null");
System.out.println(e.getMessage());
return null;
}
}
Everything is handled within the getApples
function and when _resultSet.next()
is called I get a NullPointerException
and the prints in the getApples exception so I am able to find the error and debug quickly.
Initialize rs to null first.
public ResultSet getApples (){
ResultSet rs = null;
try{
PreparedStatement stmt = con.prepareStatement("SELECT * FROM fruit WHERE type='apples'");
rs = stmt.executeQuery();
} catch (SQLException e){
e.printStackTrace();
}
return rs;
}
You can declare your RS like this
ResultSet rs = null;
but where you call your function:
ResultSet apples = getApples ()
you have to check:
if(apples == null)
{
//do something, because your query did not work.
}
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