struts2对Ognl的打包-ClassResolver

Ognl的扩展点：

http://java12345678.iteye.com/blog/2031790

OGNL ClassResolver接口 :

    用于由类名到类路径中找到Class文件，并加载生成Class对象，以支持静态属性或方法的调用

Struts对ClassResolver 的扩展：

 

 Struts中ClassResolver的加载：

  OgnlValueStack类（Struts对Ognl的封装类）:

  protected void setRoot(XWorkConverter xworkConverter, CompoundRootAccessor accessor, CompoundRoot compoundRoot,
                           boolean allowStaticMethodAccess) {
        this.context = Ognl.createDefaultContext(this.root, accessor, new OgnlTypeConverterWrapper(xworkConverter), securityMemberAccess);
    }

 CompoundRootAccessor类源码：

 public Class classForName(String className, Map context) throws ClassNotFoundException {
        Object root = Ognl.getRoot(context);

        try {
            if (root instanceof CompoundRoot) {
                if (className.startsWith("vs")) {//？？？？没明白呢
                    CompoundRoot compoundRoot = (CompoundRoot) root;

                    if ("vs".equals(className)) {
                        return compoundRoot.peek().getClass();
                    }

                    int index = Integer.parseInt(className.substring(2));

                    return compoundRoot.get(index - 1).getClass();
                }
            }
        } catch (Exception e) {
            if (LOG.isDebugEnabled()) {
                LOG.debug("Got exception when tried to get class for name [#0]", e, className);
            }
        }

        return Thread.currentThread().getContextClassLoader().loadClass(className);
    }