随书代码 上面有书中的大部分代码

				//: net/mindview/util/Directory.java
				// Produce a sequence of File objects that match a
				// regular expression in either a local directory,
				// or by walking a directory tree.
				package net.mindview.util;
				import java.util.regex.*;
				import java.io.*;
				import java.util.*;
				
				public final class 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();
				      }
				    });
				  }
				  public static File[]
				  local(String path, final String regex) { // Overloaded
				    return local(new File(path), regex);
				  }
				  // A two-tuple for returning a pair of objects:
				  public static class TreeInfo implements Iterable {
				    public List files = new ArrayList();
				    public List dirs = new ArrayList();
				    // The default iterable element is the file list:
				    public Iterator iterator() {
				      return files.iterator();
				    }
				    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) { // Begin recursion
				    return recurseDirs(new File(start), regex);
				  }
				  public static TreeInfo
				  walk(File start, String regex) { // Overloaded
				    return recurseDirs(start, regex);
				  }
				  public static TreeInfo walk(File start) { // Everything
				    return recurseDirs(start, ".*");
				  }
				  public static TreeInfo walk(String start) {
				    return recurseDirs(new File(start), ".*");
				  }
				  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 // Regular file
				        if(item.getName().matches(regex))
				          result.files.add(item);
				    }
				    return result;
				  }
				  // Simple validation test:
				  public static void main(String[] args) {
				    if(args.length == 0)
				      System.out.println(walk("."));
				    else
				      for(String arg : args)
				       System.out.println(walk(arg));
				  }
				} ///:~