code: public static final Map<String,JarEntry> findClassByJar(JarFile jarFile) throws IOException {
  		Map<String,JarEntry> map=new HashMap<String,JarEntry>();
  		if(jarFile==null)
  		{
  			throw new RuntimeException("jarFile is Null");
  		}
  		String Suffix=".class";
  		Enumeration<JarEntry> jarEntries = jarFile.entries();
  		while (jarEntries.hasMoreElements()) 
  		{//遍历jar的实体对象
  			JarEntry jarEntry = jarEntries.nextElement();
  			if(jarEntry.isDirectory() || !jarEntry.getName().endsWith(Suffix))
  			{
  				continue;
  			}
  			String jarEntryName = jarEntry.getName(); // 类似：sun/security/internal/interfaces/TlsMasterSecret.class
  			String className = jarEntryName.substring(0, jarEntryName.length() - Suffix.length());//sun/security/internal/interfaces/TlsMasterSecret
  			//注意,jar文件里面的只能是/不能是\
  			className = className.replace("/", ".");//sun.security.internal.interfaces.TlsMasterSecret
  			map.put(className,jarEntry);
  		}
  		return map;
  	}
docs: 搜索jar里面的class
  注意jar的open和close
  返回类名和类的map集合
  @throws IOException