[java][io][File]目录工具

import java.io.File;
import java.io.FilenameFilter;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.regex.Pattern;

public final class DirUtil {
	
	//produce a sequence of File objects that match a regular expression in a local directory
	public static File[] local(File dir, final String regex){
		return dir.listFiles(new FilenameFilter(){
			
			private Pattern pattern = Pattern.compile(regex);

			public boolean accept(File dir,String name ) {
				return pattern.matcher(new File(name).getName()).matches();
			}
			
		});
	}
	//overload local(File,String)
	public static File[] local(String path, final String regex){
		return local(new File(path),regex);
	}
	
	public static class TreeInfo implements Iterable<File>{
		
		public List<File> files = new ArrayList<File>();
		public List<File> dirs = new ArrayList<File>();
		
		public Iterator<File> iterator(){
			return files.iterator();
		}

		public void addAll(TreeInfo other){
			files.addAll(other.files);
			dirs.addAll(other.dirs);
		}
		
		public String toString(){
			return "dirs: " + PPrint.pformat(dirs) + "\n\nfiles: " + PPrint.pformat(files);
		}
		
	}
	
	public static TreeInfo walk(String start, String regex){
		return recurseDirs(new File(start), regex);
	}
	
	public static TreeInfo walk(File start, String regex){
		return recurseDirs(start, regex);
	}
	
	public static TreeInfo walk(String start){
		return walk(start,".*");
	}
	
	public static TreeInfo walk(File start){
		return walk(start,".*");
	}
	
	//dir recursion
	static TreeInfo recurseDirs(File startDir, String regex){
		TreeInfo result = new TreeInfo();
		for(File item : startDir.listFiles()){
			if(item.isDirectory()){
				result.dirs.add(item);
				result.addAll(recurseDirs(item,regex));
			}else{
				if(item.getName().matches(regex)){
					result.files.add(item);
				}
			}
		}
		return result;
	}
	
	public static void main(String[] args) {
		//System.out.println(walk(".",".*l.java"));
		PPrint.pprint(local(".",".*\\.*"));
		//PPrint.pprint(walk(".").dirs);
		//PPrint.pprint(walk(".").files);
	}

}


import java.util.Arrays;
import java.util.Collection;

public class PPrint {
	
	public static String pformat(Collection<?> c){
		if(c.size()==0){
			return "[]";
		}
		StringBuilder result = new StringBuilder("[");
		for(Object item : c){
			if(c.size()!=1){
				result.append("\n ");
			}
			result.append(item);
		}
		if(c.size()!=1){
			result.append("\n");
		}
		result.append("]");
		return result.toString();
	}
	
	public static void pprint(Collection<?> c){
		System.out.println(pformat(c));
	}
	
	public static void pprint(Object[] os){
		System.out.println(pformat(Arrays.asList(os)));
	}

}



import java.io.File;
import java.io.IOException;
/**
 * 遍历目录，根据策略处理目录中的文件
 *
 */
public class ProcessFiles {
	
	public interface Strategy{
		public void process(File file);
	}
	
	private Strategy strategy;
	private String ext;
	
	public ProcessFiles(Strategy strategy, String ext){
		this.strategy = strategy;
		this.ext = ext;
	}
	
	public void start(String[] args){
		try {
			if(args.length==0){
				processDirTree(new File("."));
			}else{
				for(String arg : args){
					File fileArg = new File(arg);
					if(fileArg.isDirectory()){
						processDirTree(fileArg);
					}else{
						if(!arg.endsWith("." + ext)){
							arg += "." + ext;
						}
						strategy.process(new File(arg).getCanonicalFile());
					}
				}
			}
		} catch (IOException e) {
			throw new RuntimeException(e);
		}
	}

	public void processDirTree(File file) throws IOException {
		for(File child : DirUtil.walk(file.getAbsolutePath(), ".*\\." + ext)){
			strategy.process(child.getCanonicalFile());
		}
	}
	
	public static void main(String[] args) {
		new ProcessFiles(new ProcessFiles.Strategy(){

			public void process(File file) {
				System.out.println(file);
			}
			
		},"java").start(new String[]{"."});
	}
	

}