Javaファイルの操作のオブジェクトは、いくつかのメソッドが一般的に使用される（推奨）ファイル

// Build the file object
File file=new File("E:/android_demo/a");
File fileTest=new File("E:/android_demo/a/test.mp3");

//Get the parent path of the file
File f=file.getParentFile();
System.out.println("f=="+f);//E:\android_demo

//Determine if the file exists
boolean is=file.exists();//doesn't exist, return fasle
System.out.println("is=="+is);

//Get the absolute path of the file can be understood as equivalent to getPath
String path1=file.getAbsolutePath();
System.out.println("path=="+path1);//E:\android_demo\a

//Get the path of the file
String path2=file.getPath();
System.out.println("path2=="+path2);//E:\android_demo\a

//Get the current file name
String s=file.getName();
System.out.println("s==="+s);

// Create a folder, i.e., E:/android_demo/a
file.mkdir();

//create a file, i.e., E:/android_demo/a/test.mp3

fileTest.createNewFile();
// file size, the number of bytes occupied when the file is stored.
long l=f.length();
System.out.println("l=="+l);

//Get the file path string
String str=fileTest.toString();
System.out.println("str=="+str);// E:\android_demo\a\test.mp3

// Rename the file
File fileTest2=new File("E:/android_demo/a/test2.mp3");
boolean b2=fileTest.renameTo(fileTest2);
System.out.println("b2=="+b2);// E:/android_demo/a/test2.mp3

// Delete the file
boolean b3=fileTest.delete();

//delete the folder, note that there must be no files under the deleted folder before it can be deleted, if there are, you should facilitate the deletion of all files before deleting
boolean b4=file.delete();