Java 7 for Absolute Beginners

CHAPTER 8 ■ WRITING AND READING FILES

Listing 8-3. Getting a File object for an existing file

package com.apress.java7forabsolutebeginners.examples;

import java.io.File;

public class FileTest {

public static void main(String[] args) {

String fileName = "C:" + File.separator +

"test" + File.separator + "myFile.txt";

File myFile = new File(fileName);

System.out.println(fileName + " exists? " + myFile.exists());

}

}

Notice how the creation of a File object is the same, regardless of whether the file exists or not. As

we saw earlier in this chapter, a File object is not a file. A File object is a path specification (which might

or might not exist on the file system) and some other information that might or might correspond to an

actual file. Just specifying a path and creating a new File object for it does not create a new file or prove

an existing file exists. To do that, we have to take further steps, as shown in Listings 8-1 and 8-2 (where

we used the createnewFile() method) and Listing 8-3 (where we used the exists() method).

Deleting a File

Sometimes, you need to delete a file, too. The process parallels that of creating a new or finding an

existing file. Listing 8-4 shows the simplest way to do it.

Listing 8-4. Deleting a file

package com.apress.java7forabsolutebeginners.examples;

import java.io.File;

import java.io.IOException;

public class FileTest {

public static void main(String[] args) throws IOException {

String fileName = "C:" + File.separator +

"test" + File.separator + "myFile.txt";

File myFile = new File(fileName);

if(!myFile.exists()) {

throw new IOException("Cannot delete " + fileName

+ " because" + fileName + " does not exist");

} else {

myFile.delete();

}

System.out.println(fileName + " exists? " + myFile.exists());

}

}