Java中新建一个文件、目录及路径操作实例_开发_开发者

前言

学习Java中如何新建文件、目录、路径

1-文件、目录、路径

文件	fileName，就如我们在电脑中看到的.txt、.java、.doc等
目录	dir，可以理解成文件夹，里面可以包含多个文件夹或文件
路径	directoryPath，有绝对路径和相对路径，这个不需要多说，但需要注意的是，如果想把win11电脑上已经存在的路径用来创建File实例，需要注意加转义符

2-在当前路径下创建一个文件

Main.java

class MainActivity{
	public static void main(String[] args){
		System.out.println("Main thread is running...");
		FileTest1.createAFileInCurrentPath("DefaultJavaFile1.java", null);
	}
}

FileTest1.java

import java.io.*;
class FileTest1{
	// the path of the fileName
	String directoryPath;
	// the name of the fileName
	String fileName;
	FileTest1(){
	}
	FileTest1(String directoryPath, String fileName){
		this.directoryPath = directoryPath;
		this.fileName = fileName;
	}
	static void createAFileInCurrentPath(String fileName, String directoryPath){
		if (null == directoryPath){
			directoryPath = ".";
		}
		File tempFile = new File(directoryPath, fileName);
		try{
			tempFile.createNewFile();
		}catch (IOException e){
			System.out.println("文件创建异常！");
		}
	}
}

上面的代码中，如果createAFileInCurrentPath方法传入的directoryPath为"."也是可以的，就表示当前路径

3-在当前路径下创建一个文件夹（目录）

3.1 测试1-路径已经存在

Main.java

import java.io.*;

class MainActivity{
	public static void main(String[] args){
		System.out.println("Main thread is running...");
		
		String existedPath1 = "D:\\JavaandroidLearnningDiary\\《Java 2实用教程》（5版 耿祥义、张跃平）\\Chapter10\\Leson1";
		String testFileName1 = "实习日志.java";
		
		//create a file in current path
		FileTest1.createAFileInCurrentPath("DefaultJavaFile1.java", ".");
		
		//create a file in certain path
		File testFile1 = new File(existedPath1, testFileName1);
		FileTest1.createAFileInCertainPath(testFile1);
	}
}

FileTest1.java

import java.io.*;
class FileTest1{
	// the path of the fileName
	String directoryPath;
	// the name of the fileName
	String fileName;
	FileTest1(){
	}
	FileTest1(String directoryPath, String fileName){
		this.directoryPath = directoryPath;
		this.fileName = fileName;
	}
	static void createAFileInCurrentPath(String fileName, String directoryPath){
		if (null == directoryPath){
			directoryPath = ".";
		}
		File tempFile = new File(directoryPath, fileName);
		try{
			tempFile.createNewFile();
		}catch (IOException e){
			System.out.println("文件创建异常！");
		}
	}
	static void createAFileInCertainPath(File file){
		try{
			file.createNewFile();
		}catch(Exception e){
			System.out.println(e);
		}
	}
}

测试结果：编译通过、解释运行正常，创建了新文件

3.2 测试2-路径不存在

Main.java

import java.io.*;

class MainActivity{
	public static void main(String[] args){
		System.out.println("Main thread is running...");
		
		String existedPath1 = "D:\\JavaAndroidLearnningDiary\\《Java 2实用教程》（5版 耿祥义、张跃平）\\Chapter10\\Leson1\\Lesson1~4_Review1";
		String testFileName1 = "实习日志.java";
		
		String unExistedPath1 = "D:\\JavaAndroidLearnningDiary\\《Java 2实用教程》（5版 耿祥义、张跃平）\\Chapter10\\Leson1\\Lesson1~4_Review1\\testDir1";
		String testFileName2 = "学习笔记.java";
		
		//create a file in current path
		FileTest1.createAFileInCurrentPath("DefaultJavaFile1.java", ".");
		
		//create a file in certain and existed path
		File testFile1 = new File(existedPath1, testFileName1);
		FileTest1.createAFileInCertainPath(testFile1);
		//create a file in certain but not existed path
		File testFile2 = new File(unExistedPath1, testFileName2);
		FileTest1.createAFileInCertainPath(testFile2);
	}
}

FileTest1.java

import java.io.*;

class FileTest1{
	// the path of the fileName
	String directoryPath;
	// the name of the fileName
	String fileName;
	
	FileTest1(){
		
	}
	
	FileTest1(String directoryPath, String fileName){
		this.directoryPath = directoryPath;
		this.fileName = fileName;
	}
	
	static void createAFileInCurrentPath(String fileName, String directoryPath){
		if (null == directoryPath){
			directoryPath = ".";
		}
		File tempFile = new File(directoryPath, fileName);
		try{
			tempFile.createNewFile();
		}catch (IOException e){
			System.out.println("文件创建异常！");
		}
	}
	
	static void createAFileInCertainPath(File file){
		try{
			file.createNewFile();
		}catch(Exception e){
			System.out.println(e);
		}
	}
}

测试结果如下

Java中新建一个文件、目录及路径操作实例

3.2 创建不存在的路径并新建文件

Main.java

import java.io.*;

class MainActivity{
	public static void main(String[] args){
		System.out.println("Main thread is running...");
		
		String existedPath1 = "D:\\JavaAndroidLearnningDiary\\《Java 2实用教程》（5版 耿祥义、张跃平）\\Chapter10\\Leson1\\Lesson1~4_Review1";
		String testFileName1 = "实习日志.java";
		
		String unExistedPath1 = "D:\\JavaAndroidLearnningDiary\\《Java 2实用教程》（5版 耿祥义、张跃平）\\Chapter10\\Leson1\\Lesson1~4_Review1\\testDir1";
		String testFileName2 = "学习笔记.java";
		
		//create a file in current path
		FileTest1.createAFileInCurrentPath("DefaultJavaFile1.java", ".");
		
		//create a file in certain and existed path
		File testFile1 = new File(existedPath1);
		FileTest1.createAFileInCertainPath(testFile1);
		
		//create a file in certain but not existedwww.devze.com path
		
		FileTest1.createAFileInCertainPath(testFileName2, unExistedPath1);
	}
}

FileTest1.java

import java.io.*;

class FileTest1{
	// the path of the fileName
	String directoryPath;
	// the name of the fileName
	String fileName;
	
	FileTest1(){
		
	}
	
	FileTest1(String directoryPath, String fileName){
		this.directoryPath = directoryPath;
		this.fileName = fileName;
	}
	
	static void createAFileInCurrentPath(String fileName, String directoryPath){
		if (null == directoryPath){
			directoryPath = ".";
		}
		File tempFile = new File(directoryPath, fileName);
		try{
			tempFile.createNewFile();
		}catch (IOException e){
			System.out.println("文件创建异常！");
		}
	}
	
	static void createAFileInCertainPath(File file){
		try{
			if (file.exists()){
				file.createNewFile();
			}else{
				System.out.println("the path is not existed ! here are the information of the path:");
				System.out.println("Name :"+file.getName());
				System.out.println("AbsoluteFile :"+file.getAbsoluteFile());
				System.out.println("AbsolutePath :"+file.getAbsolutePath());
			}
			
		}catch(Exception e){
			System.out.println(e);
		}
	}
	
	static void createAFileInCertainPath(String fileName, String directoryPath){
		File tempFileName, tempDirectoryPath;
		
		if (null != directoryPath){
			tempDirectoryPath = new File(directoryPath);
			System.out.println("Is tempFileNameandroid a directory :"+tempDirectoryPath.isDirectory());
			tempDirectoryPath.mkdirs();
		}
		if (null != fileName){
			tempFileName = new File(directoryPath, fileName);
			System.out.println("Is tempFileName a file :"+tempFileName.isFile());
			try{
				tempFileName.createNewFile();
			}catch(Exception e){
				System.out.println("在未存在的路径下创建文件失败！");
			}
		}
	}
}

测试结果：编译通过、解释运行，创建成功

3.3 删除已存在的文件并新建

Main.java

import java.io.*;

class MainActivity{
	public static void main(String[] args){
		System.out.println("Main thread is running...");
		
		String existedPath1 = "D:\\JavaAndroidLearnningDiary\\《Java 2实用教程》（5版 耿祥义、张跃平）\\Chapter10\\Leson1\\Lesson1~4_Review1";
		String testFileName1 = "实习日志.java";
		
		String unExistedPath1 = "D:\\JavaAndroidLearnningDiary\\《Java 2实用教程》（5版 耿祥义、张跃平）\\Chapter10\\Leson1\\Lesson1~4_Review1\\testDir2";
		String testFileName2 = "学习笔记.java";
		
		//create a file in current path
		
		//create a file in certain and existed path
		File testFile1 = new File(existedPath1);
		FileTest1.createAFileInCertainPath(testFile1);
		
		//create a file in certain but not existed path
		FileTest1.createAFileInCertainPath(testFileName2, unExistedPath1);
		
		//delete a file in current path
		FileTest1.编程deleteAFileInCurrentPath("DefaultJavaFile1.java");
		
		//delete a file in certain path
		String deleteTestPath1 = "D:\\TestPath1\\TestDir1\pythonTestDir2\\TestDir3\\TestDir3_1\\测试.txt";
		FileTest1.deleteAFileInCeratainPath("D:\\TestPath1\\TestDir1\\TestDir2\\TestDir3\\TestDir3_1", "测试.txt");
		
		//delete a dir in certain path
		FileTest1.deleteADirInCertainPath("D:\\TestPath1\\TestDir1\\TestDir2\\TestDir3\\TestDir3_2");
	}
}

FileTest1.java

impphport java.io.*;

class FileTest1{
	// the path of the fileName
	String directoryPath;
	// the name of the fileName
	String fileName;
	
	FileTest1(){
		
	}
	
	FileTest1(String directoryPath, String fileName){
		this.directoryPath = directoryPath;
		this.fileName = fileName;
	}
	
	static void createAFileInCurrentPath(String fileName, String directoryPath){
		if (null == directoryPath){
			directoryPath = ".";
		}
		File tempFile = new File(directoryPath, fileName);
		try{
			tempFile.createNewFile();
		}catch (IOException e){
			System.out.println("文件创建异常！");
		}
	}
	
	static void createAFileInCertainPath(File file){
		try{
			if (!file.exists()){
				file.createNewFile();
			}else{
				
			}
			
		}catch(Exception e){
			System.out.println(e);
		}
	}
	
	static void createAFileInCertainPath(String fileName, String directoryPath){
		File tempFileName, tempDirectoryPath;
		
		if (null != directoryPath){
			tempDirectoryPath = new File(directoryPath);
			System.out.println("Is tempFileName a directory :"+tempDirectoryPath.isDirectory());
			tempDirectoryPath.mkdirs();
		}
		if (null != fileName){
			tempFileName = new File(directoryPath, fileName);
			System.out.println("Is tempFileName a file :"+tempFileName.isFile());
			try{
				tempFileName.createNewFile();
			}catch(Exception e){
				System.out.println("在未存在的路径下创建文件失败！");
			}
			
		}
		
	}
	
	static void deleteAFileInCurrentPath(String fileName){
		System.out.println("Function deleteAFileInCurrentPath is running---------");
		File tempFile = new File(fileName);
		try{
			if (tempFile.exists()){
				System.out.println(tempFile.getName()+" 文件存在");
				tempFile.delete();
			}else{
				System.out.println("文件不存在");
			}
		}catch(Exception e){
			System.out.println("删除文件失败！");
		}
		System.out.println("Function deleteAFileInCurrentPath is finished---------");
	}
	
	static void deleteAFileInCeratainPath(String directory, String fileName){
		System.out.println("Function deleteAFileInCeratainPath is running---------");
		File tempFile = new File(directory, fileName);
		try{
			if (tempFile.exists()){
				System.out.println(tempFile.getName()+" 文件存在");
				tempFile.delete();
			}else{
				System.out.println("文件不存在");
			}
		}catch(Exception e){
			System.out.println("删除文件失败！");
		}
		System.out.println("Function deleteAFileInCeratainPath is finished---------");
	}
	
	static void deleteADirInCertainPath(String directory){
		System.out.println("Function deleteADirInCertainPath is running---------");
		File tempFile = new File(directory);
		try{
			if (tempFile.exists()){
				System.out.println(tempFile.getName()+" 文件存在");
				tempFile.delete();
			}else{
				System.out.println("文件不存在");
			}
		}catch(Exception e){
			System.out.println("删除文件失败！");
		}
		System.out.println("Function deleteADirInCertainPath is finished---------");
	}
}

4-总结

1.简要学习了Java中如何创建文件、目录

2.在调试过程中遇到了一些问题

（1）导包，本来想使用Nullable，但似乎没有相关包

（2）直接在java文件的目录下打开的Windows power Shell窗口中运行时，显示无法加载主类MainActivity，而打开的cmd窗口却可以运行

（3）如果实例化的File对象中的路径是磁盘里不存在的，则isFile、isDirectory全返回false

附：java根据路径创建文件夹

import java.io.File;

public class CreateFolderExample {
    public static void main(String[] args) {
        String folderPath = "path/to/folder";
        File folder = new File(folderPath);
        
        if (folder.exists()) {
            System.out.println("文件夹已存在");
            return;
        }
        
        if (folder.mkdir()) {
            System.out.println("文件夹创建成功");
        } else {
            System.out.println("文件夹创建失败");
        }
    }
}

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