need help in understanding exceptions

[786snow]

Hi, I am trying to understand how exception work. I understand the code below.

  try {
        BufferedReader in = new BufferedReader(new FileReader("infilename.txt"));
        String str;
        while ((str = in.readLine()) != null) {
            //process(str);
             System.out.print("it did not works");

        }
        in.close();
    } 
    
    catch (FileNotFoundException ex) {
       System.out.print("file not found");
    }
}
    
    catch (IOException e) {  System.out.print("file can not be opened");
        e.printStackTrace();
    }

 
}

But I do not understand in the following code they decalaed "throws IOException' in the method declaration with out any catch and try, how does that work?

public void readFile(Sring filename) throws IOException {


while (numBytes <= myBuffer.length){  myInputStream.read(myBuffer);
nymByres;++
}

 

[Diancecht]

Basically, it considers the exception will be caught outside the method.

http://java.sun.com/docs/books/tutorial/essential/exceptions/

Cheers,
Dian

 

[ronnyjljr]

When you use that method you are required to enclose the call in a try/catch statement. This means the calling function will deal with any errors that occur, rather than the called function.

[blue]
YourObject obj = new YourObject();

try
{
  obj.readFile("test.txt");
}
catch (IOException e)
{
  [green]//You are dealing with the error which occured in the read File method where you called it in the code, rather than inside the readfile method.[/green]
  System.out.println("Something happened!\n"+e.toString());
}

[/blue]

But, please be sure to read the link posted by Diancecht.


Hope that helps,
Ron


typedef map<GiantX,gold, less<std::shortestpathtogold> > AwesomeMap;