IO，File对象-构造函数和常用方法

import java.io.File;
import java.text.DateFormat;
import java.util.Date;

public class FileDemo {
    public static void main(String[] args) throws Exception{
        creatAndDelect();
        getDemo();
        isDmeo();
        reNameToName();
        listDemo();
        listRootDmeo();
    }
    // 1， 获取
    public static void getDemo() {
        // 文件或文件夹名称
        File file = new File("D:/1.txt");
        // 绝对路劲
        String name = file.getName();
        System.out.println(name);
        // 相对路径
        String absolutePath = file.getAbsolutePath();
        System.out.println(absolutePath);
        // 文件大小
        long len = file.length();
        System.out.println(len);
        // 最后一次修改时间
        long time = file.lastModified();
        Date date = new Date(time);
        DateFormat dateFormat = DateFormat.getDateTimeInstance(DateFormat.FULL, DateFormat.FULL);
        String str_time = dateFormat.format(date);
        System.out.println(str_time);
    }
    // 2， 创建和删除
    public static void creatAndDelect() throws Exception{
        File file = new File("D:\\2.txt");
        boolean b = file.mkdirs();
        System.out.println(b);
        System.out.println(file.delete());
        //文件
//        File file2 = new File("D:\\3.txt");
//        boolean b1 = file2.createNewFile();
//        boolean b2 = file2.delete();
//        System.out.println(b1);
//        System.out.println(b2);
    }
    // 3， 判断
    public static void isDmeo() {
        File file = new File("D:\\1.txt");
        //存在
        System.out.println("exists:" + file.exists());
        //目录
        System.out.println("isDirectory:" + file.isDirectory());
        //文件
        System.out.println("isFile:" + file.isFile());
        //隐藏
        System.out.println("isHidden:" + file.isHidden());
    }
    // 4， 重命名
    public static void reNameToName() {
        File file = new File("D:\\1.txt");
        File f = new File("D:\\4.txt");
        System.out.println(file.renameTo(f));
    }
    // 5， 系统根目录和容量获取
    public static void listRootDmeo() {
        File file[] = File.listRoots();
        for(File f : file) {
            System.out.println(f);
            System.out.println("FreeSpace:" + f.getFreeSpace());
            System.out.println("TotalSpace:" + f.getTotalSpace());
            System.out.println("UsableSpace:" + f.getUsableSpace());
        }
    }
    
    public static void listDemo() {
        File file = new File("C:\\");
        String names[] = file.list();
        for(String name : names) {
            System.out.println(name);
        }
    }
}