java读写文件一

写入文件后可逆序输出

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

public class Test3 {
	public static void main(String[] args) {
		//创建文件对象
		File file= new File("2.txt");
		
		if (file.exists()) {
			//文件存在
			String name= file.getName();
			long len= file.length();
			//判断文件隐藏属性
			boolean hidden= file.isHidden();
			System.out.println("文件名称: "+ name+ "\n文件长度: "+ len+ "\n隐藏属性: "+ hidden);
			writefile(file);
			readfile(file);
		}else {
			//文件不存在，创建文件
			try {
				file.createNewFile();
			} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}finally {
				System.out.println("文件已创建");
			}
		}
	}

	private static void readfile(File file) {
		// TODO Auto-generated method stub
		try {
		FileInputStream fileInputStream= new FileInputStream(file);
		
		byte[] b= new byte[1024];
		
		int len= fileInputStream.read(b);
		fileInputStream.close();
		StringBuilder ab = new StringBuilder(new String(b, 0, len));
		
		System.out.println("文件读出的内容是: \n"+ ab.reverse().toString());
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}

	private static void writefile(File file) {
		// TODO Auto-generated method stub
		Scanner in= new Scanner(System.in);
		System.out.println("请输入要写入得内容");
		String string= in.next();
		
		//建立文件传输管道
		try {
			FileOutputStream fileOutputStream= new FileOutputStream(file);
			
			//写文件
			fileOutputStream.write(string.getBytes());
			
			//关闭管道
			fileOutputStream.close();
			System.out.println("文件写入完成");
		} catch (FileNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		
	}
}