java 常用的文件操作

三种文件创建方操作：

import org.testng.annotations.Test;

import java.io.File;
import java.io.IOException;


public class FileTest {
    public static void main(){

    }
    //方式1
    @Test
    public void create1() throws IOException {
        String filePath = "d:\\file1.txt";
        File file = new File(filePath);
        try {
            file.createNewFile();
            System.out.println("创建文件1成功");
        }catch (IOException e){
            e.printStackTrace();
        }

    }
    //方式2
    @Test
    public void create2(){
        File parentFile = new File("D:\\");
        String fileName = "file2.txt";
        File file = new File(parentFile,fileName);

        try {
            file.createNewFile();
            System.out.println("文件2 创建成功");
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }
    //方式3
    @Test
    public void create3(){
        String parentPath = "d:\\";
        String filePath = "file3.txt";


        File file = new File(parentPath,filePath);

        try {
            file.createNewFile();
            System.out.println("文件3创建成功");
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }
}

获取文件的相关信息：

 常见方法：

import org.testng.annotations.Test;

import javax.xml.transform.Source;
import javax.xml.transform.sax.SAXSource;
import java.io.File;
import java.sql.SQLOutput;

public class FileFormation {
    public static void main(String[] args){

    }
    // 获取文件信息
    @Test
    public void Info(){
        //先创建文件对象
        File file = new File("D:\\file1.txt");


        //调用相应方法，得到相应信息
        System.out.println("文件名称："+file.getName());
        System.out.println("文件绝对路径："+file.getAbsoluteFile());
        System.out.println("文件父目录："+file.getParent());
        System.out.println("文件大小（字节）："+file.length());
        System.out.println("文件是否存在："+file.exists());
        System.out.println("是否是文件："+file.isFile());
        System.out.println("是否是目录："+file.isDirectory());
    }
}

目录的操作：

import org.testng.annotations.Test;

import java.io.File;

public class FileDirectory {
    public static void main(String[] args){

    }
    @Test
    //删除文件
    public void FileDelete(){
        String filePath = "D:\\file1.txt";
        File file = new File(filePath);

        if(file.exists()) {
            if (file.delete()) {
                System.out.println(filePath + " 删除成功");
            } else {
                System.out.println(filePath + " 删除失败");
            };
        }else{
            System.out.println(filePath+ " 文件不存在");
        }
    }

    //删除目录
    @Test
    public void FileDeleteD(){
        String filePath = "D:\\file1.txt";
        File file = new File(filePath);
        if(file.exists()) {
            if (file.delete()) {
                System.out.println(filePath + "删除成功");
            } else {
                System.out.println(filePath + "删除失败");
            };
        }else{
            System.out.println(filePath+ "目录不存在");
        }
    }
    //判断目录是否存在，不存在就创建
    @Test
    public void fileDeleteD1(){
        String dirPath = "D:\\test\\dir1.txt";
        File file = new File(dirPath);

        if(file.exists()){
            System.out.println(dirPath + "该目录已经存在");
        }else{
            if(file.mkdir()){
                System.out.println("创建成功");
            }else{
                System.out.println("创建失败");
            };
        }
    }
}