package com.MyUtils.file;

import java.io.File;
import java.io.FileFilter;
import java.io.IOException;
import java.net.JarURLConnection;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.URL;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.List;
import java.util.jar.JarEntry;
import java.util.jar.JarFile;


/**
 * 掃描包下路徑 
 * 包括本地檔案和jar包檔案
 * @author ljb
 *
 */
public class ScanningFile {
	
	private Class<?> superStrategy = String.class;//介面類class 用於過濾 可以不要
	
	private List<Class<? extends String>> eleStrategyList = new ArrayList<Class<? extends String>>();
	
	private ClassLoader classLoader = ScanningFile.class.getClassLoader();//預設使用的類載入器
	
	private static final String STARATEGY_PATH = "com.MyUtils.file";//需要掃描的策略包名
	
	public static void main(String[] args) {
		ScanningFile s = new ScanningFile();
		s.addClass();
	}
	 
    /**
	 * 獲取包下所有實現了superStrategy的類並加入list
	 */
    private void addClass(){
    	URL url = classLoader.getResource(STARATEGY_PATH.replace(".", "/"));
		String protocol = url.getProtocol();  
        if ("file".equals(protocol)) {  
            // 本地自己可見的程式碼  
       	    findClassLocal(STARATEGY_PATH);
        } else if ("jar".equals(protocol)) {  
            // 引用jar包的程式碼  
            findClassJar(STARATEGY_PATH);  
        }  
    }
    
    /**
     * 本地查詢
     * @param packName
     */
	private void findClassLocal(final String packName){
		URI url = null ;
		try {
			url = classLoader.getResource(packName.replace(".", "/")).toURI();
		} catch (URISyntaxException e1) {
			throw new RuntimeException("未找到策略資源");
		}
		
		File file = new File(url);
		file.listFiles(new FileFilter() {
				
				public boolean accept(File chiFile) {
					if(chiFile.isDirectory()){
						findClassLocal(packName+"."+chiFile.getName());
					}
					if(chiFile.getName().endsWith(".class")){
						Class<?> clazz = null;
						try {
							clazz = classLoader.loadClass(packName + "." + chiFile.getName().replace(".class", ""));
						} catch (ClassNotFoundException e) {
							e.printStackTrace();
						}
						System.out.println(chiFile);
						if(superStrategy.isAssignableFrom(clazz)){
							eleStrategyList.add((Class<? extends String>) clazz);
						}
						return true;
					}
					return false;
				}
			});
		 
	}
	
	/**
	 * jar包查詢
	 * @param packName
	 */
	private void findClassJar(final String packName){
		String pathName = packName.replace(".", "/");
		JarFile jarFile  = null;
		try {
			URL url = classLoader.getResource(pathName);
			JarURLConnection jarURLConnection  = (JarURLConnection )url.openConnection();
			jarFile = jarURLConnection.getJarFile();  
		} catch (IOException e) {
			throw new RuntimeException("未找到策略資源");
		}
		
		Enumeration<JarEntry> jarEntries = jarFile.entries();
        while (jarEntries.hasMoreElements()) {
            JarEntry jarEntry = jarEntries.nextElement();
            String jarEntryName = jarEntry.getName();
            
            if(jarEntryName.contains(pathName) && !jarEntryName.equals(pathName+"/")){
            	//遞迴遍歷子目錄
            	if(jarEntry.isDirectory()){
            		String clazzName = jarEntry.getName().replace("/", ".");
                    int endIndex = clazzName.lastIndexOf("."); 
                    String prefix = null;  
                    if (endIndex > 0) {  
                    	prefix = clazzName.substring(0, endIndex);  
                    }  
                    findClassJar(prefix);
            	}
            	if(jarEntry.getName().endsWith(".class")){
    				Class<?> clazz = null;
    				try {
    					clazz = classLoader.loadClass(jarEntry.getName().replace("/", ".").replace(".class", ""));
    				} catch (ClassNotFoundException e) {
    					e.printStackTrace();
    				}
    				if(superStrategy.isAssignableFrom(clazz)){
    					eleStrategyList.add((Class<? extends String>) clazz);
    				}
            	}
            }
            
        }
		 
	 }
	
}
 

可以去過濾實現了特點介面的類