jdk7.NIO.2学习笔记之目录文件及权限

最新推荐文章于 2025-09-07 20:32:33 发布

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最新推荐文章于 2025-09-07 20:32:33 发布

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文章标签： java

原文链接：http://www.cnblogs.com/or2-/p/3653582.html

本文通过实例演示了Java NIO2中Path API的基本用法，包括路径操作、文件创建与删除、权限设置及读写文件等内容，并介绍了Path与File类之间的转换。

package com.zl.jdk7;

import java.io.File;
import java.io.IOException;
import java.nio.file.Path;
import java.nio.file.Paths;

public class PathTest1 {
public static void main(String[] args) {
Path listing = Paths.get("/home/c3t/1.js");
//得到文件名
System.out.println("File name :"+listing.getFileName());
//获得名称元素的数量，就是目录的数量
System.out.println("number of name elements :"+listing.getNameCount());
//获得父目录路径
System.out.println("parent path :"+listing.getParent());
//得到根目录
System.out.println("Root path :"+listing.getRoot());
//得到根目录(0)到期第二个元素(2)之间的子目录
System.out.println("Subpath from root :" + listing.subpath(0, 2));

try {
//.vimrc是一个软链接 得到链接的真实文件地址
Path realPath = Paths.get("/home/c3t/.vimrc").toRealPath();
System.out.println("real path:"+realPath.toString());
} catch (final Exception e) {
e.printStackTrace();
}

//合并目录,合并后 /home/c3t/conf/application
Path prefix = Paths.get("/home/c3t/");
Path completePath = prefix.resolve("conf/application");
System.out.println("resolve:"+completePath.toString());

//获得两个路径之间的路径 结果得到 从 /usr目录到/home/c3t/waller的路径 relativeize:../home/c3t/waller
String logging ="/usr";
String configuation = "/home/c3t/waller";
Path logdir = Paths.get(logging);
Path confDir = Paths.get(configuation);
Path pathtoConfDir = logdir.relativize(confDir);
System.out.println("relativeize:"+pathtoConfDir.toString());


//NIO.2 PATH和java已有的file类转换
//java.io.File新增了 toPath方法可以把已有的File转化为Path
//Path有toFile可以把path转化为File

File file = new File("/home/c3t/1.js");
Path lp = file.toPath();
System.out.println("file to Path:"+lp.toAbsolutePath().toString());
file = lp.toFile();
}
}

//创建文件
Path target = Paths.get("/home/c3t/jdk7.txt");
//设置文件权限 由于目录权限限制 结果可能是 rw-r--r--
Set<PosixFilePermission> perms= PosixFilePermissions.fromString("rw-rw-rw-");
FileAttribute<Set<PosixFilePermission>> attr = PosixFilePermissions.asFileAttribute(perms);

//创建文件
try {
Files.createFile(target,attr);
} catch (IOException e) {
e.printStackTrace();
}

//删除文件
try {
Files.delete(target);
} catch (IOException e) {
e.printStackTrace();
}

　　自定义权限的删除和添加

  Path profile = Paths.get("/home/c3t/1.js");
        try {
            //获得属性视图
            PosixFileAttributes attrs = Files.readAttributes(profile, PosixFileAttributes.class);
            //得到权限集合
            Set<PosixFilePermission> posixFilePermission = attrs.permissions();
            //清除所有权限
            posixFilePermission.clear();
            //得到文件爱你所有者
            String owner = attrs.owner().getName();
            //得到权限的字符串形式
            String perms = PosixFilePermissions.toString(posixFilePermission);
            //加入自定义权限
            posixFilePermission.add(PosixFilePermission.OWNER_READ);
            posixFilePermission.add(PosixFilePermission.OWNER_WRITE);
            posixFilePermission.add(PosixFilePermission.OTHERS_READ);
            posixFilePermission.add(PosixFilePermission.OTHERS_WRITE);

            //写入权限
            Files.setPosixFilePermissions(profile,posixFilePermission);

        } catch (IOException e) {
            e.printStackTrace();
        }

//读文件
    @Test
    public void test2() {
        Path profile = Paths.get("/home/c3t/1.js");
        try (BufferedReader reader = Files.newBufferedReader(profile, StandardCharsets.UTF_8)) {
            String line;
            while ((line = reader.readLine()) != null) {
                System.out.println(line);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    //追加写文件
    @Test
    public void test3() {
        Path profile = Paths.get("/home/c3t/1.js");
        try (BufferedWriter writer = Files.newBufferedWriter(profile, StandardCharsets.UTF_8, StandardOpenOption.APPEND)) {
            writer.newLine();
            writer.write("i am ok");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

转载于:https://www.cnblogs.com/or2-/p/3653582.html