commonsIO工具类的使用

1、下载jar文件：commonsIO工具包

2、导入到工程中去

操作

文件和文件夹的大小：FileUtils.sizeOf()

public class io_commonsIO_test {
    public static void main(String[] args) {
        //文件大小
        long len= FileUtils.sizeOf(new File("E:/idea/io_commonsIO_study/io_commonsIO_study.iml"));
        System.out.println(len);
        //文件夹大小
        len=FileUtils.sizeOfDirectory(new File("E:/idea/io_commonsIO_study"));
        System.out.println(len);
    }
}

遍历子孙级文件

public class io_commonsIO_test02 {
    public static void main(String[] args) {
        //过滤空文件，null为第一层目录
        Collection<File> files=FileUtils.listFiles(new File("E:/idea/io_commonsIO_study"), EmptyFileFilter.NOT_EMPTY,null);
        for (File fs:files
             ) {
            System.out.println(fs.getAbsolutePath());
        }
        System.out.println("--------------------------");
        //过滤空文件，递归目录
        files=FileUtils.listFiles(new File("E:/idea/io_commonsIO_study"), EmptyFileFilter.NOT_EMPTY, DirectoryFileFilter.INSTANCE);
        for (File fs:files
        ) {
            System.out.println(fs.getAbsolutePath());
        }
        System.out.println("--------------------------");
        //递归列出后缀为.java的文件
        files=FileUtils.listFiles(new File("E:/idea/io_commonsIO_study"),
                new SuffixFileFilter("java"), DirectoryFileFilter.INSTANCE);
        for (File fs:files
        ) {
            System.out.println(fs.getAbsolutePath());
        }
        System.out.println("--------------------------");
        //递归列出后缀为.java和.class的文件和空文件
        files=FileUtils.listFiles(new File("E:/idea/io_commonsIO_study"),
                FileFilterUtils.or(new SuffixFileFilter("java"),new SuffixFileFilter("class"),EmptyFileFilter.EMPTY),DirectoryFileFilter.INSTANCE);
        for (File fs:files
        ) {
            System.out.println(fs.getAbsolutePath());
        }
        System.out.println("--------------------------");
    }
}

读取文件

public class io_commonsIO_test03 {
    public static void main(String[] args) throws IOException {
        //读取文件
        String msg =FileUtils.readFileToString(new File("empty.txt"),"utf-8");
        System.out.println(msg);
        System.out.println("----------------");
        //读取文件存入字节数组
        byte[]datas=FileUtils.readFileToByteArray(new File("empty.txt"));
        System.out.println(datas.length);
        System.out.println("------------------");
        //逐行读取
        List<String>list=FileUtils.readLines(new File("empty.txt"),"utf-8");
        for (String sr:list
             ) {
            System.out.println(sr);
        }
        System.out.println("---------------");
    }
}

写出内容

public class io_commonsIO_test04 {
    public static void main(String[] args) throws IOException {
        //写出文件
        FileUtils.write(new File("happycode.txt"),"山东扒鸡，买一送一！\r\n","utf-8");
        FileUtils.writeStringToFile(new File("happycode.txt"),"山东扒鸡，买一送一！\r\n","utf-8",true);
        //写出列表
        List<String>datas=new ArrayList<>();
        datas.add("扒鸡");
        datas.add("山扒");
        datas.add("德扒");
        FileUtils.writeLines(new File("happycode.txt"),datas,"===",true);
    }
}

文件拷贝

public class io_commonsIO_test05 {
    public static void main(String[] args) throws IOException {
       复制文件
        FileUtils.copyFile(new File("io.png"),new File("io_copy.png"));
        复制文件到目录
        FileUtils.copyFileToDirectory(new File("io.png"),new File("lib"));
        复制目录到目录，成为子目录
        FileUtils.copyDirectoryToDirectory(new File("lib"),new File("lib2"));
        复制目录
        FileUtils.copyDirectory(new File("lib"),new File("lib2"));
        拷贝URl内容
        String url="http://down-update.qq.com/dnf/website/wallpaper/201907/201907b.rar";
        FileUtils.copyURLToFile(new URL(url),new File("C:/Users/tfp12/Desktop/DNF.rar"));
        String baidu=IOUtils.toString(new URL("http://www.baidu.com"),"utf-8");
        System.out.println(baidu);
    }
}