File类

import org.junit.Test;

import java.io.File;
import java.io.IOException;
import java.util.Date;

/**
 * @author xianyu
 * @time 2019-08-16-19:16
 */
public class demo1 {

    @Test
    public void test(){

        //File类

        //构造器1
        File file1 = new File("hello.txt");  // 相对路径
        File file2 = new File("E:\\FileTest\\hi.txt");  // 绝对路径


        System.out.println(file1.getAbsolutePath());   //获取绝对路径  E:\ThirdApp\day02\hello.txt
        System.out.println(file1.getPath());           //获取路径      hello.txt
        System.out.println(file1.getName());           //获取名字      hello.txt
        System.out.println(file1.getParent());         //获取上层路径   null
        System.out.println(file1.length());            //获取文件大小   11个字节
        System.out.println(new Date(file1.lastModified()));      //获取文件最后一次修改时间   Sat Aug 17 21:24:19 CST 2019


        System.out.println("*****************************");

        System.out.println(file2.getAbsolutePath());   //获取绝对路径        E:\FileTest\hi.txt
        System.out.println(file2.getPath());           //获取路径            E:\FileTest\hi.txt
        System.out.println(file2.getName());           //获取名字            hi.txt
        System.out.println(file2.getParent());         //获取上层路径         E:\FileTest
        System.out.println(file2.length());            //获取文件长度         10个字节
        System.out.println(new Date(file2.lastModified()));      //获取文件最后一次修改时间    Sat Aug 17 21:27:06 CST 2019

        System.out.println("*****************************");

        //也可以获取目录
        //构造器2
        File file3 = new File("E:\\FileTest","Demo");


        //构造器3
        File file4 = new File(file3,"good.txt");
        System.out.println(file4.getAbsolutePath());   //获取绝对路径        E:\FileTest\Demo\good.txt
        System.out.println(file4.getPath());           //获取路径            E:\FileTest\Demo\good.txt
        System.out.println(file4.getName());           //获取名字            good.txt
        System.out.println(file4.getParent());         //获取上层路径        E:\FileTest\Demo
        System.out.println(file4.length());            //获取文件长度        13个字节
        System.out.println(new Date(file4.lastModified()));      //获取文件最后一次修改时间    Sat Aug 17 21:32:15 CST 2019


        System.out.println("*****************************");
        File file5 = new File("E:\\halo");

        String[] nameList = file5.list();     //获取指定目录下所有文件或文件目录的名称String数组

        for(String s : nameList){
            System.out.println(s);
        }

        System.out.println("*****************************");

        File[] nameList2 = file5.listFiles();  //获取指定目录下所有文件或文件目录的名称File数组
        for(File s : nameList2){
            System.out.println(s);
        }

        System.out.println("*****************************");

    }


    @Test
    public void test2(){

        File file = new File("hello.txt");

        System.out.println(file.isDirectory());          //判断是否是文件目录
        System.out.println(file.isFile());               //判断是否是文件
        System.out.println(file.exists());               //判断文件是否存在
        System.out.println(file.canRead());              //判断文件是否可读
        System.out.println(file.canWrite());             //判断文件是否可写
        System.out.println(file.isHidden());             //判断文件是否隐藏

    }




    @Test
    public void test3() throws IOException {

        File file = new File("hello1.txt");
        if(!(file.exists())){
            //如果文件不存在就创建文件
            file.createNewFile();
            System.out.println("创建成功！！！！");
        }else{
            file.delete();
            System.out.println("删除成功");
        }
    }

    @Test
    public void test7(){
        //文件目录的创建
        File file1 = new File("e:\\io\\io1\\io3");

        boolean mkdir = file1.mkdir();
        if(mkdir){
            System.out.println("创建成功1");
        }

        File file2 = new File("e:\\io\\io1\\io4");

        boolean mkdir1 = file2.mkdirs();
        if(mkdir1){
            System.out.println("创建成功2");
        }
        //要想删除成功，io4文件目录下不能有子目录或文件
//        File file3 = new File("e:\\io\\io1\\io4");
        File file3 = new File("e:\\io\\io1");
        System.out.println(file3.delete());
    }



}

E:\ThirdApp\day02\hello.txt
hello.txt
hello.txt
null
11
Sat Aug 17 21:24:19 CST 2019
*****************************
E:\FileTest\hi.txt
E:\FileTest\hi.txt
hi.txt
E:\FileTest
10
Sat Aug 17 21:27:06 CST 2019
*****************************
E:\FileTest\Demo\good.txt
E:\FileTest\Demo\good.txt
good.txt
E:\FileTest\Demo
13
Sat Aug 17 21:32:15 CST 2019
*****************************
.gitattributes
.github
.gitignore
.gradle
.idea
.travis.yml
build.gradle
Dockerfile
gradle
gradlew
gradlew.bat
LICENSE
lombok.config
out
README.md
scripts
settings.gradle
src
*****************************
E:\halo\.gitattributes
E:\halo\.github
E:\halo\.gitignore
E:\halo\.gradle
E:\halo\.idea
E:\halo\.travis.yml
E:\halo\build.gradle
E:\halo\Dockerfile
E:\halo\gradle
E:\halo\gradlew
E:\halo\gradlew.bat
E:\halo\LICENSE
E:\halo\lombok.config
E:\halo\out
E:\halo\README.md
E:\halo\scripts
E:\halo\settings.gradle
E:\halo\src
*****************************