IO流复制文件——做一个文件拷贝的小练习（IO流）

以前学过IO流，那时候也做了很多联系，不过好像忘了一些了，现在做个小练习巩固一下，主要针对子文件夹拷贝的递归操作
现在我的D盘有两个文件夹dir1(内含子文件夹和文件)和dir2(空)，我想把整个dir1拷贝到dir2下面

视频演示

dir1和dir2

dir1中的文件和子文件夹

dir2现在为空，待会我们要把dir1中的所有拷贝到这里来

代码实现

import java.io.*;

class FileUtil {
    private File srcFile;
    private File desFile;
    /**
     * 构造
     */
    public FileUtil(String oldFile, String newFile) {
        // 利用路径字符串来创建文件
        this.srcFile = new File(oldFile);
        // 新文件 = 新文件所在的路径 + 系统分隔符 + 原文件的路径
        this.desFile = new File(newFile + File.separator + this.srcFile.getName());
    }
    public FileUtil(File srcFile, File desFile) {
        this.srcFile = srcFile;
        this.desFile = desFile;
    }
    /**
     * 拷贝
     */
    public boolean copy() {
        if (!srcFile.exists()) {
            System.out.println("原文件不存在！");
            return false;
        }
        try {
            copyImpy(srcFile);
            return true;
        } catch (Exception e) {
            return false;
        }
    }
    /**
     * 复制的核心代码，利用了递归
     */
    public void copyImpy(File file) throws IOException {
        // 判断是一个目录
        if (file.isDirectory()) {
            File[] files = file.listFiles();
            if (files != null) {
                for (File f : files) {
                    copyImpy(f);
                }
            }
        }
        // 判断是一个文件
        else {
            // 文件目录 = 原文件路径 - 原文件最外层路径 - 系统分隔符
            String path = file.getPath().replace(srcFile.getPath() + File.separator, "");
            // 新文件路径（包含子文件夹） = 目的文件夹 + 子文件夹路径
            File newFile = new File(this.desFile, path);
            // 调用文件拷贝函数
            copyFileImpl(file, newFile);
        }
    }
    /**
     * 复制文件
     */
    public void copyFileImpl(File srcFile, File desFile) throws IOException {
        // 如果目标路径不存在，就创建路径，可能有多层文件夹，故用mkdirs()
        if (!desFile.getParentFile().exists()) {
            desFile.getParentFile().mkdirs();
        }
        InputStream inputStream = new FileInputStream(srcFile);
        OutputStream outputStream = new FileOutputStream(desFile);
        // 后台输出拷贝情况
        System.out.println("正在从 " + srcFile.getParent() + " 拷贝文件 " + srcFile.getName() + " 到" + desFile.getParent());
        // 字节数组，相当于一个缓冲区
        byte[] date = new byte[1024];
        // 一次性读出的字节长度
        int len = 0;
        while ((len = inputStream.read(date)) != -1) {
            // 将缓存数组的数据写入到新文件
            outputStream.write(date, 0, len);
        }
        // 关闭流
        inputStream.close();
        outputStream.close();
    }
}

public class Main {
    public static void main(String[] args) {
        // 两个参数，一个表示原文件及路径，一个表示目的路径
        if (args.length != 2) {
            System.out.println("初始化数据错误！");
            return;
        }
        FileUtil fileUtil = new FileUtil(args[0], args[1]);
        if (fileUtil.copy()) {
            System.out.println("拷贝成功！");
        } else {
            System.out.println("拷贝失败！");
        }
    }
}

控制台实时输出

正在从 D:\dir1 拷贝文件 boot-crm.rar 到D:\dir2\dir1
正在从 D:\dir1 拷贝文件 idea使用教程2017-06-01.pdf 到D:\dir2\dir1
正在从 D:\dir1 拷贝文件 ssmchapter01.rar 到D:\dir2\dir1
正在从 D:\dir1\ssmchapter02\ssmchapter02 拷贝文件 pom.xml 到D:\dir2\dir1\ssmchapter02\ssmchapter02
正在从 D:\dir1\ssmchapter02\ssmchapter02\src\main\Java\com\ssm\annotation 拷贝文件 AnnotationAssembleTest.java 到D:\dir2\dir1\ssmchapter02\ssmchapter02\src\main\Java\com\ssm\annotation
正在从 D:\dir1\ssmchapter02\ssmchapter02\src\main\Java\com\ssm\annotation 拷贝文件 UserController.java 到D:\dir2\dir1\ssmchapter02\ssmchapter02\src\main\Java\com\ssm\annotation
正在从 D:\dir1\ssmchapter02\ssmchapter02\src\main\Java\com\ssm\annotation 拷贝文件 UserDao.java 到D:\dir2\dir1\ssmchapter02\ssmchapter02\src\main\Java\com\ssm\annotation
正在从 D:\dir1\ssmchapter02\ssmchapter02\src\main\Java\com\ssm\annotation 拷贝文件 UserDaoImpl.java 到D:\dir2\dir1\ssmchapter02\ssmchapter02\src\main\Java\com\ssm\annotation
正在从 D:\dir1\ssmchapter02\ssmchapter02\src\main\Java\com\ssm\annotation 拷贝文件 UserService.java 到D:\dir2\dir1\ssmchapter02\ssmchapter02\src\main\Java\com\ssm\annotation
正在从 D:\dir1\ssmchapter02\ssmchapter02\src\main\Java\com\ssm\annotation 拷贝文件 UserServiceImpl.java 到D:\dir2\dir1\ssmchapter02\ssmchapter02\src\main\Java\com\ssm\annotation
正在从 D:\dir1\ssmchapter02\ssmchapter02\src\main\Java\com\ssm\assemble 拷贝文件 User.java 到D:\dir2\dir1\ssmchapter02\ssmchapter02\src\main\Java\com\ssm\assemble
正在从 D:\dir1\ssmchapter02\ssmchapter02\src\main\Java\com\ssm\assemble 拷贝文件 XmlBeanAssembleTest.java 到D:\dir2\dir1\ssmchapter02\ssmchapter02\src\main\Java\com\ssm\assemble
正在从 D:\dir1\ssmchapter02\ssmchapter02\src\main\Java\com\ssm\instance\constructor 拷贝文件 Bean1.java 到D:\dir2\dir1\ssmchapter02\ssmchapter02\src\main\Java\com\ssm\instance\constructor
正在从 D:\dir1\ssmchapter02\ssmchapter02\src\main\Java\com\ssm\instance\constructor 拷贝文件 InstanceTest1.java 到D:\dir2\dir1\ssmchapter02\ssmchapter02\src\main\Java\com\ssm\instance\constructor
正在从 D:\dir1\ssmchapter02\ssmchapter02\src\main\Java\com\ssm\instance\factory 拷贝文件 Bean3.java 到D:\dir2\dir1\ssmchapter02\ssmchapter02\src\main\Java\com\ssm\instance\factory
正在从 D:\dir1\ssmchapter02\ssmchapter02\src\main\Java\com\ssm\instance\factory 拷贝文件 InstanceTest3.java 到D:\dir2\dir1\ssmchapter02\ssmchapter02\src\main\Java\com\ssm\instance\factory
正在从 D:\dir1\ssmchapter02\ssmchapter02\src\main\Java\com\ssm\instance\factory 拷贝文件 MyBean3Factory.java 到D:\dir2\dir1\ssmchapter02\ssmchapter02\src\main\Java\com\ssm\instance\factory
正在从 D:\dir1\ssmchapter02\ssmchapter02\src\main\Java\com\ssm\instance\static_factory 拷贝文件 Bean2.java 到D:\dir2\dir1\ssmchapter02\ssmchapter02\src\main\Java\com\ssm\instance\static_factory
正在从 D:\dir1\ssmchapter02\ssmchapter02\src\main\Java\com\ssm\instance\static_factory 拷贝文件 InstanceTest2.java 到D:\dir2\dir1\ssmchapter02\ssmchapter02\src\main\Java\com\ssm\instance\static_factory
正在从 D:\dir1\ssmchapter02\ssmchapter02\src\main\Java\com\ssm\instance\static_factory 拷贝文件 MyBean2Factory.java 到D:\dir2\dir1\ssmchapter02\ssmchapter02\src\main\Java\com\ssm\instance\static_factory
正在从 D:\dir1\ssmchapter02\ssmchapter02\src\main\Java\com\ssm\scope 拷贝文件 Scope.java 到D:\dir2\dir1\ssmchapter02\ssmchapter02\src\main\Java\com\ssm\scope
正在从 D:\dir1\ssmchapter02\ssmchapter02\src\main\Java\com\ssm\scope 拷贝文件 ScopeTest.java 到D:\dir2\dir1\ssmchapter02\ssmchapter02\src\main\Java\com\ssm\scope
正在从 D:\dir1\ssmchapter02\ssmchapter02\src\main\resources 拷贝文件 beans1.xml 到D:\dir2\dir1\ssmchapter02\ssmchapter02\src\main\resources
正在从 D:\dir1\ssmchapter02\ssmchapter02\src\main\resources 拷贝文件 beans2.xml 到D:\dir2\dir1\ssmchapter02\ssmchapter02\src\main\resources
正在从 D:\dir1\ssmchapter02\ssmchapter02\src\main\resources 拷贝文件 beans3.xml 到D:\dir2\dir1\ssmchapter02\ssmchapter02\src\main\resources
正在从 D:\dir1\ssmchapter02\ssmchapter02\src\main\resources 拷贝文件 beans4.xml 到D:\dir2\dir1\ssmchapter02\ssmchapter02\src\main\resources
正在从 D:\dir1\ssmchapter02\ssmchapter02\src\main\resources 拷贝文件 beans5.xml 到D:\dir2\dir1\ssmchapter02\ssmchapter02\src\main\resources
正在从 D:\dir1\ssmchapter02\ssmchapter02\src\main\resources 拷贝文件 beans6.xml 到D:\dir2\dir1\ssmchapter02\ssmchapter02\src\main\resources
正在从 D:\dir1\ssmchapter02\ssmchapter02\src\main\webapp 拷贝文件 index.jsp 到D:\dir2\dir1\ssmchapter02\ssmchapter02\src\main\webapp
正在从 D:\dir1\ssmchapter02\ssmchapter02\src\main\webapp\WEB-INF 拷贝文件 web.xml 到D:\dir2\dir1\ssmchapter02\ssmchapter02\src\main\webapp\WEB-INF
正在从 D:\dir1\ssmchapter02 拷贝文件 第2章 Spring中的Bean.pdf 到D:\dir2\dir1\ssmchapter02
正在从 D:\dir1 拷贝文件 ssmchapter02.rar 到D:\dir2\dir1
正在从 D:\dir1\ssmchapter03\ssmchapter03 拷贝文件 pom.xml 到D:\dir2\dir1\ssmchapter03\ssmchapter03
正在从 D:\dir1\ssmchapter03\ssmchapter03\src\main\Java\com\ssm\aspect 拷贝文件 MyAspect.java 到D:\dir2\dir1\ssmchapter03\ssmchapter03\src\main\Java\com\ssm\aspect
正在从 D:\dir1\ssmchapter03\ssmchapter03\src\main\Java\com\ssm\aspectj\annotation 拷贝文件 MyAspect.java 到D:\dir2\dir1\ssmchapter03\ssmchapter03\src\main\Java\com\ssm\aspectj\annotation
正在从 D:\dir1\ssmchapter03\ssmchapter03\src\main\Java\com\ssm\aspectj\annotation 拷贝文件 TestAnnotationAspectj.java 到D:\dir2\dir1\ssmchapter03\ssmchapter03\src\main\Java\com\ssm\aspectj\annotation
正在从 D:\dir1\ssmchapter03\ssmchapter03\src\main\Java\com\ssm\aspectj\xml 拷贝文件 MyAspect.java 到D:\dir2\dir1\ssmchapter03\ssmchapter03\src\main\Java\com\ssm\aspectj\xml
正在从 D:\dir1\ssmchapter03\ssmchapter03\src\main\Java\com\ssm\aspectj\xml 拷贝文件 TestXmlAspectj.java 到D:\dir2\dir1\ssmchapter03\ssmchapter03\src\main\Java\com\ssm\aspectj\xml
正在从 D:\dir1\ssmchapter03\ssmchapter03\src\main\Java\com\ssm\cglib 拷贝文件 CglibProxy.java 到D:\dir2\dir1\ssmchapter03\ssmchapter03\src\main\Java\com\ssm\cglib
正在从 D:\dir1\ssmchapter03\ssmchapter03\src\main\Java\com\ssm\cglib 拷贝文件 CglibTest.java 到D:\dir2\dir1\ssmchapter03\ssmchapter03\src\main\Java\com\ssm\cglib
正在从 D:\dir1\ssmchapter03\ssmchapter03\src\main\Java\com\ssm\cglib 拷贝文件 UserDao.java 到D:\dir2\dir1\ssmchapter03\ssmchapter03\src\main\Java\com\ssm\cglib
正在从 D:\dir1\ssmchapter03\ssmchapter03\src\main\Java\com\ssm\factorybean 拷贝文件 MyAspect.java 到D:\dir2\dir1\ssmchapter03\ssmchapter03\src\main\Java\com\ssm\factorybean
正在从 D:\dir1\ssmchapter03\ssmchapter03\src\main\Java\com\ssm\factorybean 拷贝文件 ProxyFactoryBeanTest.java 到D:\dir2\dir1\ssmchapter03\ssmchapter03\src\main\Java\com\ssm\factorybean
正在从 D:\dir1\ssmchapter03\ssmchapter03\src\main\Java\com\ssm\jdk 拷贝文件 JdkProxy.java 到D:\dir2\dir1\ssmchapter03\ssmchapter03\src\main\Java\com\ssm\jdk
正在从 D:\dir1\ssmchapter03\ssmchapter03\src\main\Java\com\ssm\jdk 拷贝文件 JdkTest.java 到D:\dir2\dir1\ssmchapter03\ssmchapter03\src\main\Java\com\ssm\jdk
正在从 D:\dir1\ssmchapter03\ssmchapter03\src\main\Java\com\ssm\jdk 拷贝文件 UserDao.java 到D:\dir2\dir1\ssmchapter03\ssmchapter03\src\main\Java\com\ssm\jdk
正在从 D:\dir1\ssmchapter03\ssmchapter03\src\main\Java\com\ssm\jdk 拷贝文件 UserDaoImpl.java 到D:\dir2\dir1\ssmchapter03\ssmchapter03\src\main\Java\com\ssm\jdk
正在从 D:\dir1\ssmchapter03\ssmchapter03\src\main\resources 拷贝文件 applicationContext.xml 到D:\dir2\dir1\ssmchapter03\ssmchapter03\src\main\resources
正在从 D:\dir1\ssmchapter03\ssmchapter03\src\main\resources 拷贝文件 applicationContext1.xml 到D:\dir2\dir1\ssmchapter03\ssmchapter03\src\main\resources
正在从 D:\dir1\ssmchapter03\ssmchapter03\src\main\resources 拷贝文件 applicationContext2.xml 到D:\dir2\dir1\ssmchapter03\ssmchapter03\src\main\resources
正在从 D:\dir1\ssmchapter03\ssmchapter03\src\main\webapp 拷贝文件 index.jsp 到D:\dir2\dir1\ssmchapter03\ssmchapter03\src\main\webapp
正在从 D:\dir1\ssmchapter03\ssmchapter03\src\main\webapp\WEB-INF 拷贝文件 web.xml 到D:\dir2\dir1\ssmchapter03\ssmchapter03\src\main\webapp\WEB-INF
正在从 D:\dir1\ssmchapter03 拷贝文件 第3章 Spring AOP.pdf 到D:\dir2\dir1\ssmchapter03
正在从 D:\dir1 拷贝文件 ssmchapter03.rar 到D:\dir2\dir1
正在从 D:\dir1 拷贝文件 ssmchapter04.rar 到D:\dir2\dir1
拷贝成功！

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文件夹dir2情况

成功拷贝！

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代码编译器：IntelliJ IDEA 2020.1