Java：从文件读取时，扫描仪不接受try-catch类错误

Question

At Java 8 documentation, it is written that the constructor from Scanner which receives a File Source as parameter throws a FileNotFoundException . But take a look at the following code:

  try{
            sc = new Scanner("Rede.txt");      //This archive already exists
        }
        catch(FileNotFoundException f){
            f.printStackTrace;
        }
        finally{
            sc.close();
        }

When I run it, I get something like:

error:exception FileNotFoundException is never thrown in body of corresponding try statement
              catch(FileNotFoundException f){

Same happens with IOException . The curious is that, if I throw away the try-catch part, the code compiles.

What is wrong here?

Answer 1

Scanner can also scan a String. To see what I mean, try:

System.out.println( new Scanner("Rede.txt").next() );

It will print Rede.txt .

Some other classes (like eg FileInputStream) will take a String path, but Scanner doesn't. If you want to use a file, you need to actually pass it a File:

sc = new Scanner(new File("Rede.txt"));