18th Java I/O stream (2)

1. Get all files or folders in the specified directory

1  Packagecn.itcast_01;2 ImportJava.io.File;3 Importjava.io.IOException;4 /**5 * Requirements: Gets all files and directories in the specified directory (returns an array of names or a file array)6  */7  Public classFileDemo5 {8      Public Static voidMain (string[] args) {9         //To create a file object and specify an abstract path nameTenFile File =NewFile ("E:"); One         //list () returns an array of names AString[] s =file.list (); -          for(String string:s) { - System.out.println (string); the         } -System.out.println ("--------"); -file[] ListFile =file.listfiles (); -          for(File f:listfile) { + System.out.println (F.getname ()); - System.out.println (F.getpath ()); +         } A     } at}

2. Get the specified file under the specified directory

1  Packagecn.itcast_01;2 ImportJava.io.File;3 Importjava.io.IOException;4 /**5 * Requirements: Get all files in the specified directory ending in. jpg6  */7  Public classFileDemo6 {8      Public Static voidMain (string[] args)throwsIOException {9         //To create a file object specifying an abstract path nameTenFile File =NewFile ("E:"); One         //get all content in the specified directory (file array) Afile[] Files =file.listfiles (); -         //iterate through the array and determine if the condition is met -          for(File f:files) { the             if(F.isfile ()) { -                 if(F.getname (). EndsWith (". jpg")){ - System.out.println (F.getname ()); -                 } +             } -         } +     } A}

1  Packagecn.itcast_01;2 ImportJava.io.File;3 ImportJava.io.FilenameFilter;4 Importjava.io.IOException;5 /**6 * File name filter7 * Return directly to the document that meets the criteria8  */9  Public classFileDemo7 {Ten      Public Static voidMain (string[] args)throwsIOException { One         //defining a File object specifying a path AFile File =NewFile ("E:"); -         //query all files that meet the criteria -String[] s = file.list (NewFilenameFilter () { the              -              Public BooleanAccept (File dir, String name) { -                 /*File File = new file (dir,name); - Boolean Flag1 = File.isfile (); + Boolean flag2 = Name.endswith (". jpg"); - return flag1&&flag2;*/ +                 return NewFile (dir, name). Isfile () && name.endswith (". jpg"); A             } at         }); -          for(String string:s) { - System.out.println (string); -         } -     } -}

18th Java I/O stream (2)