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 # 20

Java byte input streams

The basic input stream is class InputStream. InputStream is an abstract class: it does not define how to read the data. The real functionality is provided by subclasses of InputStream .

For file handling, the most important subclass of InputStream is FileInputStream.

This is a class that can read a specified file from beginning to end.

A Java program creates a new FileInputStream like this:

File aFile = new File("readme.txt");
FileInputStream fis = new FileInputStream(aFile);

Note that the FileInputStream needs to be supplied with a file object, not a simple filename, so we have to create a File object as well. You will often see this code shortened to:

FileInputStream fis = new FileInputStream(new File("readme.txt"));

The program can read the first byte of data in the file like this:

Byte b = fis.read();

Each new call to the read() method reads the next byte in the file, until the end.

Back to top