import java.io.Serializable;

 class Person implements Serializable{

     /**

     *

     */

     private static final long serialVersionUID = 1L;

     private String name ;

     private int age ;

     public static Person p = new Person( "xyy",24);

     private Person(String name, int age ) {

          super ();

          this .name = name ;

          this .age = age ;

    }

     public static Person getPerson() {

          return p ;

    }

}

public class Demo {

     public static void main(String[] args) throws IOException, ClassNotFoundException {

         Person p=Person. p;

         ObjectOutputStream oos= new ObjectOutputStream(new FileOutputStream("C:/obj.dat" ));

          oos.writeObject( p);

          oos.close();

          ObjectInputStream ois= new ObjectInputStream( new FileInputStream("C:/obj.dat" ));

         Person p1=(Person) ois.readObject();

         System. out .println(p1 ==p );

          ois.close();

    }

}

protected Object readResolve() {

          return p ;

    }

//Paths类.用于获取Path对象.

static Path get(String first,String... more);

/*获取路径对象.将按照默认文件系统分割符组合,然后解析连接起来的结果,如果不是合法路径,抛出异常*/

//Path类.封装了一系列的路径操作

/*

如果other是绝对路径,返回绝对路径,否则返回this和other连接获得的路径

*/

Path resolve(Path other);

/*

如果other是绝对路径返回other,否则返回连接this父路径和other获得的路径

*/

Path resolveSibling(Path other);

/*

返回父路径,或者在路径没有父路径的时候,返回null

*/

Path getParent();

/*

返回该路径的最后一个部件,没有任何部件,返回null

*/

Path getFileName();

/*

从该路径中创建File对象

*/

File toFile();

//File对象提供了转化为path对象的方法

Path toPath();

//Files类封装了一系列对于文件的操作.包括输入输出流缓冲的读取.

//把文件的内容转化为字节数组.

byte[] bytes=Files.readAllBytes(path);

//希望将文件当作行序列读取,那么可以调用:

List<String> lines=Files.readAllLines(path,charset);

//将字节数组写入文件

Files.write(path,bytes);

//将行的集合写入到文件中:

Files.write(path,lines);

//获取指定文件的输入流和输出流

InputStream in=Files.newInputStream(path);

OutputStream out=Files.newOutputStream(path);

//获取指定编码的BufferedReader和指定解码的BufferedWriter

Reader in=Files.newBufferedReader(path,charset);

Writer out=Files.newBufferedWriter(path,charset);

//将一个文件复制或移动(复制并删除)到给定位置.可以代替重命名操作.

static Path copy(Path from,Path to,CopyOption... options);

static Path move(Path from,Path to,CopyOption... options);

//删除给定文件或空目录

static void delete(Path path);

static void deleteIfExits(Path path);

//创建目录(与mkdir,mkdirs一样)

static Path createFile(Path path,FileAttribute... attrs);

static Path createDirectory(Path path,FileAttribute... attrs);

static Path createDirectorys(Path path,FileAttribute... attrs);

//获取文件信息(一部分信息封装在BasicAttributes接口)

static boolean exits(Path path);    //是否存在

static boolean isHidden(Path path);    //是否隐藏

static boolean isRegularFile(Path path);    //是否是文件

static boolean isDirevtory(Path path);     //是否是文件夹

static long size(Path path);    //获取文件按字节度量的尺寸.

//通过如下操作,获取文件属性对象

PosixFileAttribute attributes=Files.readAttributes(path,BasicFileAttributes.class);

//BasicFileAttributes接口提供一系列属性信息

FileTime creationTime();   //创建时间

FileTime lastModifiedTime();       //最迟修改的时间

try(DirectoryStream<Path> entries=Files.newDirectoryStream(dir))

{

       for(Path entry:entries)

           //Process entries

}

try(DirectoryStream<Path> entries=Files.newDirectoryStream(dir,"*.txt"))

import java.io.IOException;

import java.nio.file.FileVisitResult;

import java.nio.file.FileVisitor;

import java.nio.file.Files;

import java.nio.file.Path;

import java.nio.file.Paths;

import java.nio.file.SimpleFileVisitor;

import java.nio.file.attribute.BasicFileAttributes;

public class Demo {

    public static void main(String[] args) throws IOException  {

        Path path=Paths.get("C:\\","pictures");

        printFile(path);

    }

    public static void printFile(Path path) throws IOException {

        Files.walkFileTree(path,new SimpleFileVisitor<Path>() {

            //在一个目录被处理前执行的操作

            public FileVisitResult preVisitDirectory(Path dir, BasicFileAttributes attrs) throws IOException {

                System.out.println(dir+"目录将被处理");

                return FileVisitResult.CONTINUE;

            }

            //遇见一个文件的时候执行的操作

            public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException {

                System.out.println("访问"+file+"文件");

                return FileVisitResult.CONTINUE;

            }

            //访问文件失败的时候执行的操作

            public FileVisitResult visitFileFailed(Path file, IOException exc) throws IOException {

                return FileVisitResult.CONTINUE;

            }

            //一个目录被处理后执行的操作

            public FileVisitResult postVisitDirectory(Path dir, IOException exc) throws IOException {

                System.out.println(dir+"被处理");

                return FileVisitResult.CONTINUE;

            }

        });

    }

}