JavaSE复习_11 IO流复习

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;
            }
            
        });
    }
}