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java中怎么删除文件和目录

delete()方法可用于删除文件或空目录/文件夹,如果文件被删除,delete()方法返回true,如果文件不存在则返回false。

如果删除目录,delete()方法检查目录是否为空,如果目录为空,则删除目录,否则delete()方法不会执行任何操作并返回false,所以在这种情况下,必须递归删除所有文件,然后再删除目录。

删除非空目录的另一种方法是使用Files.walkFileTree()方法,在这种方法中,可以逐个处理所有文件,并在单个文件对象上调用delete()方法。

删除文件示例:

package com.journaldev.files;import java.io.File;public class DeleteFileJava {    /**     * 此类显示如何在Java中删除文件     * @param args     */    public static void main(String[] args) {        // 带路径的文件名        File file = new File("tmp/tmp2/file.txt");        if(file.delete()){            System.out.println("tmp/tmp2/file.txt File deleted");        }else System.out.println("File tmp/tmp2/file.txt doesn't exist");        // 只提供文件名称        file = new File("file.txt");        if(file.delete()){            System.out.println("file.txt File deleted from Project root directory");        }else System.out.println("File file.txt doesn't exist in the project root directory");        //relative path        file = new File("temp/file.txt");        if(file.delete()){            System.out.println("temp/file.txt File deleted from Project root directory");        }else System.out.println("File temp/file.txt doesn't exist in the project root directory");        // 删除空的目录        file = new File("temp");        if(file.delete()){            System.out.println("temp directory deleted from Project root directory");        }else System.out.println("temp directory doesn't exist or not empty in the project root directory");        // 试图删除非空目录        file = new File("D:/user/maxsu/project");        if(file.delete()){            System.out.println("D:/user/maxsu/project directory deleted from Project root directory");        }else System.out.println("D:/user/maxsu/project directory doesn't exist or not empty");    }}

注意:与createNewFile()不同,delete方法不会抛出IOException异常。

下面是一个简单的程序,演示如何删除非空目录,如果目录包含有文件,删除目录不会成功。

删除目录示例:

import java.io.File;public class JavaDeleteDirectory {    public static void main(String[] args) {        File dir = new File("D:/worksp/java/log");        if(dir.isDirectory() == false) {            System.out.println("Not a directory. Do nothing");            return;        }        File[] listFiles = dir.listFiles();        for(File file : listFiles){            System.out.println("Deleting "+file.getName());            file.delete();        }        //现在目录为空,所以可以删除它        System.out.println("Deleting Directory. Success = "+dir.delete());    }}

递归删除目录示例:

import java.io.IOException;import java.nio.file.FileVisitResult;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 JavaDeleteDirectoryRecursively {    public static void main(String[] args) throws IOException {        Path directory = Paths.get("D:/worksp/maxsu/log");        Files.walkFileTree(directory, new SimpleFileVisitor<Path>() {           @Override           public FileVisitResult visitFile(Path file, BasicFileAttributes attributes) throws IOException {               Files.delete(file); // 有效,因为它始终是一个文件               return FileVisitResult.CONTINUE;           }           @Override           public FileVisitResult postVisitDirectory(Path dir, IOException exc) throws IOException {               Files.delete(dir); //这将起作用,因为目录中的文件已被删除               return FileVisitResult.CONTINUE;           }        });    }}

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