JVMPI动态加载jar包path入当前classloader

java本身建议创建ClassLoader子类，并完成类似addURL方法已达到动态加载类路径。但在第三方包运行时，对方已经实现了ClassLoader子类且未提供此方法。则可以利用JVMPI技术完成这一操作。

java 部分:

<com.myCom.myproj.myclass>

extClassLoader = Thread.currentThread().getContextClassLoader();
File extDir = new File( System.getProperty( "cyanea.home" )+"/lib/ext/" );
File extFiles[] = extDir.listFiles();
ArrayList loaders = null;
if( extFiles != null )
{
 for( int i = 0 ; i < extFiles.length ; i ++ )
 {
        try
        {
           loaders = addClassPath( extClassLoader, extFiles[i].toURL() );
        }catch( Exception e )
                {
                 System.out.println( "exception in addClassPath" );
                }
}

C 部分:

#include "classloader.h"

#pragma convlit(resume)

//it is a helper function to get the URL of a loader
//addClassPath will return an arraylist of loader, iterate the arraylist and call this function
//will print out the class loader loading sequence

JNIEXPORT jobject JNICALL Java_com_myCom_myproj_myclass_addClassPath( JNIEnv *env, jobject thisObject, jobject extclassloader, jobject url )
{
 jobject loaders = NULL;
 try{
  if( extclassloader == NULL || url == NULL ) throw 0;
  jclass extclassloaderclass = env->GetObjectClass( extclassloader );
  
  //add code to deal with the ClassLoader Implement Class here.
  
  //load
  jfieldID ucpid = env->GetFieldID( extclassloaderclass, "ucp", "Lsun/misc/URLClassPath;" );
  if( ucpid == NULL ) throw 5;
  jobject ucp = env->GetObjectField( extclassloader, ucpid  );
  if( ucp == NULL ) throw 6;
  jclass ucpclass = env->GetObjectClass( ucp );
  jfieldID pathid = env->GetFieldID( ucpclass, "path", "Ljava/util/ArrayList;" );
  if( pathid == NULL ) throw 7;
  jobject path = env->GetObjectField( ucp, pathid );
  if( path == NULL ) throw 8;
  jclass pathclass = env->GetObjectClass( path );
  jmethodID add2path = env->GetMethodID( pathclass, "add", "(ILjava/lang/Object;)V" );
  if( add2path == NULL ) throw 9;
  env->CallVoidMethod( path, add2path, 0, url );
  if( env->ExceptionOccurred() ) throw 10;

  jmethodID check = env->GetStaticMethodID( ucpclass, "check", "(Ljava/net/URL;)V" );
  if( check == NULL ) throw 11;
  env->CallStaticVoidMethod( ucpclass, check, url );
  if( env->ExceptionOccurred() ) throw 12;

  //create loader and add to loaders and lmap

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