Java 天地·Core Java·Lecture Notes·Unit 10 - Applications, File Handling and Exceptions

您的位置：寻梦网首页＞编程乐园＞Java天地＞Core Java＞Java Lecture Notes

Introduction

Content

Apply

Reflect

Extend

Content Index

Content Page # 18

Example of using File class

Consider a text file called examples.txt containing the following 2 lines of text:

This is a test file
it has 2 lines of text

We can write an application ( FileTest1.java ) to interrogate this file via an object of class File:

import Java.io.*;
public class FileTest1
{
public static void main( String args[] )
    {
    String fileName = "example.txt";
    File f1 = new File( fileName );
    System.out.println("properties of file " + fileName );
    System.out.println("canRead() : " + f1.canRead() );
    System.out.println("canWrite() : " + f1.canWrite() );
    System.out.println("length() : " + f1.length() );
    }
} // class

The result of running our application is the following:

If we edit examples.txt to make it contain just the character:

the output of the application is as follows:

You might like to try compiling this application, and changing the contents of file examples.txt to see the length in bytes change (note that the end of line character also takes up a byte…).

Back to top