unreported exception java.io.FileNotFoundException; must be caught or declared to be thrown

问题

I am creating a class -- just a class, no main() and I am receiving the error of "unreported exception java.io.FileNotFoundException; must be caught or declared to be thrown" at this line:

FileOutputStream outStr = new FileOutputStream(FILE, true);

I don't understand; I put in a try{} catch{} block and it's still reporting the error.

Additionally, it's also reporting an "illegal start of type" for the try and both catch lines, and it's also saying that ';' is expected for both catch lines.

I'm using the NetBean IDE, FYI.

Thank you for any help.

Here is the full code:

import java.io.FileOutputStream;
import java.io.IOException;
import java.io.PrintStream;
import java.io.FileNotFoundException;


public class UseLoggingOutputStream 
{

    String FILE = "c:\\system.txt";

    try
    {

        FileOutputStream outStr = new FileOutputStream(FILE, true);

    }

    catch(FileNotFoundException fnfe)
    {

        System.out.println(fnfe.getMessage());

    }

    catch(IOException ioe)
    {

        System.out.println(ioe.getMessage());

    }

}

回答1:

You need to put the file processing statements inside a method:

import java.io.FileOutputStream;
import java.io.FileNotFoundException;

public class UseLoggingOutputStream {
    public void myMethod() {
        String file = "c:\\system.txt";
        try {
            FileOutputStream outStr = new FileOutputStream(file, true);
        } catch(FileNotFoundException fnfe) { 
            System.out.println(fnfe.getMessage());
        } 
    }
}

回答2:

All functional code needs to go into methods - I don't see a method in your code - that's the illegal start of type problem. The other compile errors should become clearer once you get the basics down.

public class Foo {

  public void doSomething() {
    //code here 
  }

}

回答3:

Move this code to some method or at least to a static initializer block.

回答4:

import java.io.*;
import java.util.*; 

public class SortNames {

private String[] strings = new String[10];  

private int counter;

public SortNames() {

ArrayList<String> names = new ArrayList<String>();
Scanner scan = null;
File f = null;

try{
 f = new File("names.txt");
 scan = new Scanner(f);

  while(scan.hasNext()) names.add(scan.next());
}
  finally{scan.close();}

Collections.sort(names);

  for(String s:names) System.out.println(s);

     }  
}

回答5:

Sorry if this isn't helpful to you, but I was able to solve this exact issue by adding " throws FileNotFoundException " to my method call that contained the FileWriter. I know this may not be helpful since you aren't using methods, but then again, maybe it is.

来源：https://stackoverflow.com/questions/5748656/unreported-exception-java-io-filenotfoundexception-must-be-caught-or-declared-t

标签

java

exception

try-catch

filenotfoundexception