fileiostreamdemo.java

来自「JAVA编程思想源代码 值得一下 很难找的」· Java 代码 · 共 49 行

package chapter10;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;

public class FileIOStreamDemo {

	public static void main(String[] args) {
		File f = new File("C://test.txt");
		String str = "This is the input.";
		byte[] buffer = new byte[str.length()];
		buffer = str.getBytes();
		try {
			if (!f.exists()) {
				f.createNewFile();
			}
			FileInputStream input1 = new FileInputStream(f);
			FileOutputStream output = new FileOutputStream(f);
			//输入数据到文件
			output.write(buffer);
			output.write(buffer, 5, buffer.length - 5);
			output.close();
			//从文件读取数据
			byte[] b1 = new byte[input1.available()];
			//从文件开头读取所有的字节
			System.out.println("从文件读取的数据流的字节数为：" + input1.available());
			input1.read(b1);
			String s1 = new String(b1);
			System.out.println(s1);
			System.out.println("数据流读取完毕后可读取的字节数为：" + input1.available());
			FileInputStream input2 = new FileInputStream(f);
			//跳过文件开头5个字节读取后面的字节
			input2.skip(5);
			System.out.println("跳过头五个字节，从文件读取的数据流的字节数为：" + input2.available());
			byte[] b2 = new byte[input2.available()];
			input2.read(b2);
			String s2 = new String(b2);
			System.out.println(s2);
			System.out.println("数据流读取完毕后可读取的字节数为：" + input2.available());
		} catch (IOException e) {
			e.printStackTrace();
		}

	}

}