search
HomeJavajavaTutorialApplication example tutorial of FileUtils class

FileUtils class application

1. Write a file;

2. Read from the file;

3. Create a folder, including folders ;

4. Copy files and folders;

5. Delete files and folders;

6. Get files from URL address;

7. List files and folders by file filter and extension;

8. Compare file contents;

9. File last modification time;

10. Calculate checksum.

1. Method of copying files or folders:

Example:

 1 public class CopyFileorDirectory {
 2     public static void main(String[] args) throws Exception {
 3         File file1 =new File("path1");
 4         File file2 =new File("path2");
 5         File file3 =new File("path3");
 6         File file4 =new File("path4");
 7         File file5 =new File("path5");
 8         //将文件复制到指定文件夹中,保存文件日期的时间。
 9         // 该方法将指定源文件的内容复制到指定目标目录中相同名称的文件中。
10         // 如果不存在,则创建目标目录。如果目标文件存在,则该方法将覆盖它。
11         FileUtils.copyFileToDirectory(file1,file2);//文件不重命
12         //将文件复制到一个新的地方(重命名文件)并保存文件日期的时间。
13         FileUtils.copyFile(file1,file3);
14 
15         //复制文件夹到指定目录下,如果指定目录不存在则创建
16         FileUtils.copyDirectoryToDirectory(file2,file4);
17 
18         //复制文件夹到指定目录下并重命名
19         FileUtils.copyDirectory(file4,file5);
20 
21         //该方法将指定的源目录结构复制到指定的目标目录中。
22         FileUtils.copyDirectory(file4,file5, DirectoryFileFilter.DIRECTORY);
23 
24         // 复制文件夹下第一级内容中指定后缀文件
25         IOFileFilter txtSuffixFilter = FileFilterUtils.suffixFileFilter(".txt");
26         IOFileFilter txtFiles = FileFilterUtils.and(FileFileFilter.FILE, txtSuffixFilter);
27         FileUtils.copyDirectory(file4,file5, txtFiles);
28 
29         // 复制文件目录结构及文件夹下第一级目录内指定后缀文件
30         FileFilter filter = FileFilterUtils.or(DirectoryFileFilter.DIRECTORY, txtFiles);
31         FileUtils.copyDirectory(file4,file5, filter,false);//preserveFileDate参数默认为true。
32 
33         //将字节从URL源复制到文件目的地。如果它们还不存在,则将创建到目的地的目录。如果已经存在,文件将被覆盖。
34         URL source = new URL("http://imgsrc.baidu.com/baike/pic/ewe.jpg");
35         FileUtils.copyURLToFile(source,file5,1000,1000);
36 
37         // 等待NFS传播文件创建,并强制执行超时。该方法重复测试File.exists(),直到它返回true,或直到秒内指定的最大时间。
38         File file = new File("/abc/");
39         boolean d = FileUtils.waitFor(file,100);
40         System.out.println(d);
41     }
42 }

2. Method of deleting files or files

 1 public class FileorDirectoryDelete {
 2     public static void main(String[] args) throws Exception{
 3         File file = new File("path1");
 4         File directory = new File("path2");
 5         //递归删除一个目录(包括内容)。
 6         FileUtils.deleteDirectory(directory);
 7 
 8         //删除一个文件,不会抛出异常。如果文件是一个目录,删除它和所有子目录。
 9         FileUtils.deleteQuietly(file);
10 
11         //清理内容而不删除它。
12         FileUtils.cleanDirectory(directory);
13 
14         //删除一个文件,会抛出异常
15         //如果file是文件夹,就删除文件夹及文件夹里面所有的内容。如果file是文件,就删除。
16         //如果某个文件/文件夹由于某些原因无法被删除,会抛出异常
17         FileUtils.forceDelete(file);
18     }
19 }

3. Create directory

 1 public class CreatDirectory {
 2     public static void main(String[] args) throws Exception {
 3         File file = new File("path");
 4         //创建一个文件夹,如果由于某些原因导致不能创建,则抛出异常
 5         //一次可以创建单级或者多级目录
 6         FileUtils.forceMkdir(new File("/Users/wuguibin/Downloads/folder"));
 7         //为指定文件创建文件的父级目录
 8         FileUtils.forceMkdirParent(file);
 9     }
10 }

4. Move files or folders

//移动文件夹,并重新命名
FileUtils.moveDirectory(new File("/Users/Downloads/file1"),
       new File("/Users/Downloads/file2/file3"));

//移动文件夹,并给定是否重命名
FileUtils.moveDirectoryToDirectory(new File("/Users/Downloads/file1"),
       new File("/Users/Downloads/file2/"),false);
//移动文件到指定文件夹中,并重新命名
FileUtils.moveFile(file1,new File("/Users/Downloads/海葡萄.jpen"));
//移动文件到指定文件夹中,并给定是否创建文件夹
FileUtils.moveFileToDirectory(new File("/Users/Downloads/海葡萄.jpeg"),
        new File("/Users/Downloads/file2"),false);

5 , Determine whether the files are the same or contain relationships, get the size of the file or folder

//确定父目录是否包含指定子元素(一个文件或目录)。即directory是否包含file2,在比较之前,文件是标准化的。
boolean a = FileUtils.directoryContains(directory,file2);
//比较两个文件的内容,以确定它们是否相同。
boolean b = FileUtils.contentEquals(file1, file2)

//Get the size of the specified file or folder, it may overflow and become a negative value
long l = FileUtils .sizeOf(file1);
System.out.println(l+"KB");
//Get the size of the specified file or folder without overflowing
BigInteger bi= FileUtils.sizeOfAsBigInteger(file1);
System.out.println(bi+"kb");

//Recursively calculate the size of a directory (the sum of the lengths of all files).
//Note that sizeOfDirectory() does not detect overflow, and if overflow occurs, the return value may be negative. The sizeOfDirectoryAsBigInteger() method does not overflow.
FileUtils.sizeOfDirectory(file1);
FileUtils.sizeOfDirectoryAsBigInteger(file1);

6. Compare the old and new files

  //比较指定文件是否比参考文件创建或修改后时间晚
  boolean b = FileUtils.isFileNewer(file1,file2));
 
  //如果指定的文件比指定的日期更新。
  SimpleDateFormat date = new SimpleDateFormat("yyyy/MM/dd");
  String date1 = "2017/06/20";
  boolean c = FileUtils.isFileNewer(file1,date.parse(date1));
  boolean d = FileUtils.isFileNewer(file1,23243);
        
   //指定文件创建或修改后的时间是否比参考文件或日期早
   FileUtils.isFileOlder(file1,232434);
   FileUtils.isFileOlder(file1,System.currentTimeMillis());

7. Write Enter the file

 //把集合里面的内容写入文件,以指定字符串结束写入
 //void writeLines(File file,Collection> lines,String lineEnding,boolean append)
 ArrayList<string> list = new ArrayList();
 String str1 = "Java";
 String str2 = "JSP";
 list.add(str1);
 list.add(str2);
 FileUtils.writeLines(file8,"GBK",list,"java",true);

 //把字符串写入文件
 //参数1:需要写入的文件,如果文件不存在,将自动创建。  参数2:需要写入的内容
 //参数3:编码格式     参数4:是否为追加模式( ture: 追加模式,把字符串追加到原内容后面)
 String data1 = "认真";
 FileUtils.writeStringToFile(file,data1, "UTF-8", true);

 //把字节数组写入文件
 byte [] buf = {13,123,34};
 System.out.println(new String(buf));
 FileUtils.writeByteArrayToFile(file13,buf,0,buf.length,true);</string>

8. Read the file and obtain the input and output stream

 //将文件的内容读入一个字符串中。
 String str =  FileUtils.readFileToString(file,"UTF-16" ); 
 FileUtils.readFileToByteArray(file);
 //把文件读取到字节数组里面
 byte[] readFileToByteArray(final File file)

 //把文件读取成字符串 ;Charset encoding:编码格式
 String readFileToString(final File file, final Charset encoding)

 //把文件读取成字符串集合 ;Charset encoding:编码格式 List<string> list4 =FileUtils.readLines(
       new File("/Users/Shared/笔记/java.txt"),"UTF-8");
 Iterator it = list4.iterator();
 while (it.hasNext()){
      Object obj=it.next();
      System.out.println(obj);
  }


 //获取输入流
FileUtils.openInputStream(file);
 //获取输出流
FileUtils.openOutputStream(file);</string>

The above is the detailed content of Application example tutorial of FileUtils class. For more information, please follow other related articles on the PHP Chinese website!

Statement
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
How does IntelliJ IDEA identify the port number of a Spring Boot project without outputting a log?How does IntelliJ IDEA identify the port number of a Spring Boot project without outputting a log?Apr 19, 2025 pm 11:45 PM

Start Spring using IntelliJIDEAUltimate version...

How to elegantly obtain entity class variable names to build database query conditions?How to elegantly obtain entity class variable names to build database query conditions?Apr 19, 2025 pm 11:42 PM

When using MyBatis-Plus or other ORM frameworks for database operations, it is often necessary to construct query conditions based on the attribute name of the entity class. If you manually every time...

How to use the Redis cache solution to efficiently realize the requirements of product ranking list?How to use the Redis cache solution to efficiently realize the requirements of product ranking list?Apr 19, 2025 pm 11:36 PM

How does the Redis caching solution realize the requirements of product ranking list? During the development process, we often need to deal with the requirements of rankings, such as displaying a...

How to safely convert Java objects to arrays?How to safely convert Java objects to arrays?Apr 19, 2025 pm 11:33 PM

Conversion of Java Objects and Arrays: In-depth discussion of the risks and correct methods of cast type conversion Many Java beginners will encounter the conversion of an object into an array...

How do I convert names to numbers to implement sorting and maintain consistency in groups?How do I convert names to numbers to implement sorting and maintain consistency in groups?Apr 19, 2025 pm 11:30 PM

Solutions to convert names to numbers to implement sorting In many application scenarios, users may need to sort in groups, especially in one...

E-commerce platform SKU and SPU database design: How to take into account both user-defined attributes and attributeless products?E-commerce platform SKU and SPU database design: How to take into account both user-defined attributes and attributeless products?Apr 19, 2025 pm 11:27 PM

Detailed explanation of the design of SKU and SPU tables on e-commerce platforms This article will discuss the database design issues of SKU and SPU in e-commerce platforms, especially how to deal with user-defined sales...

How to set the default run configuration list of SpringBoot projects in Idea for team members to share?How to set the default run configuration list of SpringBoot projects in Idea for team members to share?Apr 19, 2025 pm 11:24 PM

How to set the SpringBoot project default run configuration list in Idea using IntelliJ...

See all articles

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

Video Face Swap

Video Face Swap

Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Tools

SublimeText3 Chinese version

SublimeText3 Chinese version

Chinese version, very easy to use

DVWA

DVWA

Damn Vulnerable Web App (DVWA) is a PHP/MySQL web application that is very vulnerable. Its main goals are to be an aid for security professionals to test their skills and tools in a legal environment, to help web developers better understand the process of securing web applications, and to help teachers/students teach/learn in a classroom environment Web application security. The goal of DVWA is to practice some of the most common web vulnerabilities through a simple and straightforward interface, with varying degrees of difficulty. Please note that this software

Dreamweaver Mac version

Dreamweaver Mac version

Visual web development tools

EditPlus Chinese cracked version

EditPlus Chinese cracked version

Small size, syntax highlighting, does not support code prompt function

Atom editor mac version download

Atom editor mac version download

The most popular open source editor