Java 解析文件后缀名(扩展名)方法总结

àì夳堔傛蜴生んèń 2023-10-10 12:42 60阅读 0赞

## 方式一：使用FilenameUtils.getExtension来获取扩展名 ##

maven 配置

<dependency>  
        <groupId>commons-io</groupId>  
        <artifactId>commons-io</artifactId>   
        <version>2.4</version>  
    </dependency>

Java 功能代码:

File file = new File("C:\\logo.png");
    		// 获取文件后缀类型
    		String suffix = FilenameUtils.getExtension(file.getPath());

## 方式二:通过使用lastIndexOf和substring方法来得到扩展名 ##

Java 功能代码:

String extension = "";
    int i = fileName.lastIndexOf('.');
    if (i > 0) {
        extension = fileName.substring(i+1);
    }

或者

String extension = "";
    int i = fileName.lastIndexOf('.');
    int p = Math.max(fileName.lastIndexOf('/'), fileName.lastIndexOf('\\'));
    if (i > p) {
        extension = fileName.substring(i+1);
    }

## 方式三:使用Guava库的Files工具类获取扩展名 ##

maven 配置:

<dependency>
       <groupId>com.google.guava</groupId>
       <artifactId>guava</artifactId>
       <version>17.0</version>
    </dependency>

Java 功能代码:

String path = "c:/path/to/file/foo.txt";
    String ext = Files.getFileExtension(path);
    System.out.println(ext); //prints txt

## 方式四:自定义获取拓展名方法（**getExtension**） ##

Java 功能代码:

public static String getExtension(String fileName) {
        char ch;
        int len;
        if(fileName==null || 
                (len = fileName.length())==0 || 
                (ch = fileName.charAt(len-1))=='/' || ch=='\\' || //in the case of a directory
                 ch=='.' ) //in the case of . or ..
            return "";
        int dotInd = fileName.lastIndexOf('.'),
            sepInd = Math.max(fileName.lastIndexOf('/'), fileName.lastIndexOf('\\'));
        if( dotInd<=sepInd )
            return "";
        else
            return fileName.substring(dotInd+1).toLowerCase();
    }

## 方式五：使用split方法来获取后缀名 ##

Java 功能代码:

String[] split = fullFileName.split("\\.");
      String ext = split[split.length - 1];