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How to implement regular expression filtering files in Java

黄舟
黄舟Original
2017-09-02 10:34:072153browse

这篇文章主要介绍了JAVA正则表达式过滤文件的实现方法的相关资料,希望通过本文大家能够掌握理解这部分内容,需要的朋友可以参考下

JAVA正则表达式过滤文件的实现方法

  正则表达式过滤文件列表,听起来简单,如果用java实现,还真需要一番周折,本文简析2种方式 

1、适用于路径确定,文件名时正则表达式的情况(jdk6的写法)

String filePattern = "/data/logs/.+\\.log"; 
File f = new File(filePattern); 
File parentDir = f.getParentFile(); 
String regex = f.getName(); 
FileSystem FS = FileSystems.getDefault(); 
final PathMatcher matcher = FS.getPathMatcher("regex:" + regex); 
 
DirectoryStream.Filter<Path> fileFilter = new DirectoryStream.Filter<Path>() { 
 @Override 
 public boolean accept(Path entry) throws IOException { 
  return matcher.matches(entry.getFileName()) && !Files.isDirectory(entry); 
 } 
}; 
 
List<File> result = Lists.newArrayList(); 
try (DirectoryStream<Path> stream = Files.newDirectoryStream(parentDir.toPath(), fileFilter)) { 
 for (Path entry : stream) { 
  result.add(entry.toFile()); 
 } 
} catch (IOException e) { 
 e.printStackTrace(); 
} 
for(File file : result) { 
 System.out.println(file.getParent() + "/" + file.getName()); 
}

2、适用于路径确定,文件名正则表达式的情况,这种正则表达式是JAVA支持的表达式,而非系统(unix)文件系统表达式(jdk8写法)

Path path = Paths.get("/data/logs"); 
Pattern pattern = Pattern.compile("^.+\\.log"); 
List<Path> paths = Files.walk(path).filter(p -> { 
 //如果不是普通的文件,则过滤掉 
 if(!Files.isRegularFile(p)) { 
  return false; 
 } 
 File file = p.toFile(); 
 Matcher matcher = pattern.matcher(file.getName()); 
 return matcher.matches(); 
}).collect(Collectors.toList()); 
 
for(Path item : paths) { 
 System.out.println(item.toFile().getPath()); 
}


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