java文件操作之Path,Paths,Files

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Java7中文件IO发生了很大的变化，专门引入了很多新的类：

import java.nio.file.DirectoryStream;
import java.nio.file.FileSystem;
import java.nio.file.FileSystems;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.attribute.FileAttribute;
import java.nio.file.attribute.PosixFilePermission;
import java.nio.file.attribute.PosixFilePermissions;

在以前的操作中，主要通过File构造一个文件，然后将File作为入参，获取输入流等操作。Api的操作不是很流畅。在新的文件IO中，用Path取代了File，用Files作为一个操作类，并且封装了很多非常实用的Api,看完下面的示例，就会有一个新的理解。

package filespaths;import org.junit.Test;import java.io.*;import java.net.URI;import java.nio.charset.StandardCharsets;import java.nio.file.FileSystems;import java.nio.file.Files;import java.nio.file.Path;import java.nio.file.Paths;import java.nio.file.attribute.PosixFilePermission;import java.util.HashSet;import java.util.List;import java.util.Set;import java.util.stream.Stream;/** * @Author kingboy * @Date 2017/4/13 11:05 * @Description Path is used to Path Sample * @email kingboyworld@163.com */public class PathTest {    private static String separator = File.separator;    /**     * 构建Path     */    @Test    public void constructon(){        //1.Paths        Path path = Paths.get("/Users/kingboy/Desktop/");        Path path1 = Paths.get(URI.create("/Users/kingboy/Desktop/"));        //2.FileSystems        Path path2 = FileSystems.getDefault().getPath("/Users/kingboy/Desktop/");        //3.File        Path path3 = new File("/Users/kingboy/Desktop/").toPath();    }    /**     * 创建一个空文件/文件夹     * @throws IOException     */    @Test    public void create() throws IOException {        //文件夹        Path path = Paths.get("/Users/kingboy/Desktop/hello");        if(!Files.exists(path)){            Files.createDirectory(path);            //创建多个目录            //Files.createDirectories(path);        }        //文件        Path path1 = Paths.get("/Users/kingboy/Desktop/helloFile");        if(Files.exists(path1)){            Files.createFile(path1);        }    }    /**     * 文件属性     */    @Test    public void getFileProperties() throws IOException {        Path path = Paths.get("/Users/kingboy/Desktop/text.txt");        System.out.println(Files.getLastModifiedTime(path));//最后修改时间        System.out.println(Files.getOwner(path));//拥有者        System.out.println(Files.getPosixFilePermissions(path));//权限        System.out.println(Files.size(path));//文件大小    }    /**     * 读取一个文本文件     */    @Test    public void readText() throws IOException {        Path path = Paths.get("/Users/kingboy/Desktop/text.txt");        //通过bufferedReader读取        BufferedReader bufferedReader = Files.newBufferedReader(path, StandardCharsets.UTF_8);//文件编码        StringBuilder sb = new StringBuilder();        String tempString = null;        while ((tempString = bufferedReader.readLine())!=null){            sb = sb.append(tempString);        }        System.out.println(sb);        //通过Files方法readAllLines        List<String> strings = Files.readAllLines(path);        strings.forEach(s -> System.out.print(s));        //输出结果        //adsfasdfasdfadsfasdfgsdfsdffsdfsdf        //adsfasdfasdfadsfasdfgsdfsdffsdfsdf    }    /**     * 拿到文件输入流     * @throws IOException     */    @Test    public void getInputStream() throws IOException {        Path path = Paths.get("/Users/kingboy/Desktop/text.txt");        InputStream inputStream = Files.newInputStream(path);    }    /**     * 文件写操作     */    @Test    public void writeFile() throws IOException {        Path path = Paths.get("/Users/kingboy/Desktop/writeFile");        BufferedWriter bufferedWriter = Files.newBufferedWriter(path);        String str = "write file test";        bufferedWriter.write(str);        bufferedWriter.flush();        bufferedWriter.close();    }    /**     * 遍历一个文件夹     */    @Test    public void traverseDirectory() throws IOException {        Path path = Paths.get("/Users/kingboy/Desktop/");        Stream<Path> list = Files.list(path);        list.forEach(p -> {            System.out.println(p.getFileName());        });    }    /**     * 遍历文件树     */    @Test    public void traverseTree() throws IOException {        Path path = Paths.get("/Users/kingboy/Desktop/");        Stream<Path> walk = Files.walk(path);        walk.forEach(path1 -> {//            System.out.println(path1.getRoot());//根目录            System.out.println(path1.getFileName());//文件名//            System.out.println(path1.getParent());//上级目录//            System.out.println(path1.getFileSystem());//文件系统        });        //还有种方式Files.walkFileTree()    }    /**     * 文件复制     */    @Test    public void copyFile() throws IOException {        Path path = Paths.get("/Users/kingboy/Desktop/text.txt");        Path path2 = Paths.get("/Users/kingboy/Desktop/hello.txt");        Files.copy(path,path2);    }    /**     * 读取权限见上面示例，设置权限     */    @Test    public void writePermission() throws IOException {        Path path = Paths.get("/Users/kingboy/Desktop/text.txt");        Set<PosixFilePermission> permissionSet = new HashSet<>();        permissionSet.add(PosixFilePermission.GROUP_WRITE);        permissionSet.add(PosixFilePermission.OWNER_EXECUTE);        Files.setPosixFilePermissions(path,permissionSet);    }    //还有很多其他操作Api,自己查看方法名，很容易就能分辨出功能。}

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