JAVA基础（File类的判断功能）

1，判断功能

public boolean isDirectory():判断是否是目录

public boolean isFile():判断是否是文件

public boolean exists():判断是否存在

public boolean canRead():判断是否可读

public boolean canWrite():判断是否可写

public boolean isHidden():判断是否隐藏

 

2，实现步骤

import java.io.File; public class Demo4_FileMethod {     /**      * * A:判断功能         * public boolean isDirectory():判断是否是目录         * public boolean isFile():判断是否是文件         * public boolean exists():判断是否存在         * public boolean canRead():判断是否可读         * public boolean canWrite():判断是否可写         * public boolean isHidden():判断是否隐藏     * B:案例演示         * File类的判断功能      */     public static void main(String[] args) {         //demo1();         File file = new File("zzz");         file.setReadable(false);         System.out.println(file.canRead());             //windows系统认为所有的文件都是可读的         file.setWritable(true);         System.out.println(file.canWrite());             //windows系统可以设置为不可写                  File file2 = new File("aaa.txt");         System.out.println(file2.isHidden());            //判断是否是隐藏文件         System.out.println(file.isHidden());     }     public static void demo1() {         File dir1 = new File("ccc");         System.out.println(dir1.isDirectory());            //判断是否是文件夹                  File dir2 = new File("zzz");         System.out.println(dir2.isDirectory());                  System.out.println(dir1.isFile());                //判断是否是文件         System.out.println(dir2.isFile());     } }