java 动态加载class问题

Question

java 动态加载class；写了A B类，都没有main方法。其中 A类中有静态方法f，其功能是动态加载类B的class文件。类B中有个函数；在idea中运行是没问题的 A.T.sum(2,7)) 可以调用。但是一旦把这个程序打成jar包后。在其他工程里引入jar包，就不能动态加载该类B。请大神指导下

package fff.BB;

/**

• Created by ***** on 2017/6/22. */ public class B { public int sum(int x, int y){ return x+y; } }

import fff.BB.B;

import java.io.File;
import java.io.IOException;
import java.net.URL;
import java.net.URLDecoder;
import java.util.Enumeration;
import java.util.LinkedHashSet;
import java.util.Set;

/**

• Created by liweidong on 2017/6/22.
  */
  public class A {
  public static B T = null;
  static {
  registerReset();
  }
  private static void registerReset(){
  Set> classSet = loadClass();
  for(Class cl : classSet){
  try {
  T = (B) cl.newInstance();
  } catch (Exception e) {
  e.printStackTrace();
  }
  }
  }

  private static Set> loadClass(){
  String packageDir = "fff.BB";
  Set> classSet = new LinkedHashSet>();
  try {
  Enumeration dirs = Thread.currentThread().getContextClassLoader().getResources(packageDir.replace('.','/'));
  while (dirs.hasMoreElements()){
  URL url = dirs.nextElement();
  String packagePath = URLDecoder.decode(url.getFile(),"UTF-8");
  Class<?> loadClass = findClass(packageDir,packagePath);
  if(loadClass != null){
  classSet.add(loadClass);
  }
  }
  }catch (IOException e){

  }
  return classSet;
  

  }

  private static Class<?> findClass(String packageName,String packagePath){
  File dir = new File(packagePath);
  if(!dir.exists() || !dir.isDirectory()){
  return null;
  }

  File[] dirfiles = dir.listFiles(file -> (file.getName().endsWith(".class")));
  
  for(File file : dirfiles){
      String className = file.getName().substring(0, file.getName().length() - ".class".length());
      Class<?> clazz = null;
      try {
          clazz = Thread.currentThread().getContextClassLoader().loadClass(packageName + "." + className);
          if(clazz != null){
              return clazz;
          }
      } catch (ClassNotFoundException e) {
          e.printStackTrace();
      }
  
  }
  return null;
  

  }
  }

Answer 1

考虑下打包成jar后路径问题