java.lang.NullPointerException
at com.opensymphony.xwork2.ognl.OgnlUtil.getBeanInfo(OgnlUtil.java:398)
at com.opensymphony.xwork2.ognl.OgnlUtil.getPropertyDescriptors(OgnlUtil.java:344)
at com.opensymphony.xwork2.ognl.OgnlUtil.getBeanMap(OgnlUtil.java:375)
at com.opensymphony.xwork2.ognl.OgnlReflectionProvider.getBeanMap(OgnlReflectionProvider.java:97)
at org.apache.struts2.components.Debug.start(Debug.java:71)
at org.apache.struts2.views.jsp.ComponentTagSupport.doStartTag(ComponentTagSupport.java:53)
at org.apache.jsp.WEB_002dINF.jsp.member2Restaurant.searchPartner_jsp._jspx_meth_s_005fdebug_005f0(searchPartner_jsp.java:272)
at org.apache.jsp.WEB_002dINF.jsp.member2Restaurant.searchPartner_jsp._jspService(searchPartner_jsp.java:183)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:432)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:749)
at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:487)
at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:412)
at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:339)
at org.apache.struts2.dispatcher.ServletDispatcherResult.doExecute(ServletDispatcherResult.java:164)
at org.apache.struts2.dispatcher.StrutsResultSupport.execute(StrutsResultSupport.java:186)
at com.opensymphony.xwork2.DefaultActionInvocation.executeResult(DefaultActionInvocation.java:374)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:278)
at com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:236)
at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249)
at com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor.intercept(ExceptionMappingInterceptor.java:187)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249)
at cn.com.eatlab.web.AuthInterceptor.intercept(AuthInterceptor.java:74)
...........
ERROR ExceptionMappingInterceptor:38 - Caught an exception while getting the property values of null- Class: com.opensymphony.xwork2.ognl.OgnlUtil
File: OgnlUtil.java
Method: getBeanInfo
Line: 398 - com/opensymphony/xwork2/ognl/OgnlUtil.java:398:-1
org.apache.jasper.JasperException: Caught an exception while getting the property values of null - Class: com.opensymphony.xwork2.ognl.OgnlUtil
File: OgnlUtil.java
Method: getBeanInfo
Line: 398 - com/opensymphony/xwork2/ognl/OgnlUtil.java:398:-1
at org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:549)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:470)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
debug进去到Debug.class文件发现这样一段代码：
public boolean start(Writer writer) {
boolean result = super.start(writer);
ValueStack stack = getStack();
Iterator iter = stack.getRoot().iterator();
List stackValues = new ArrayList(stack.getRoot().size());
while (iter.hasNext()) {
Object o = iter.next();
Map values;
try {
values = reflectionProvider.getBeanMap(o);
} catch (Exception e) {
throw new StrutsException("<span style="color:#ff0000;">Caught an exception while getting the property values of</span> " + o, e);
}
stackValues.add(new DebugMapEntry(o.getClass().getName(), values));
}
addParameter("stackValues", stackValues);
return result;
}图片
发现root中一个对象为null，此为发出异常的的原因，
接着发现jsp页面有一个<s:debug></s:debug>标签，去掉此标签后就正常了。
但是又产生了一个新的问题，debug标签就是debug用的，却因为debug标签产生bug......
搞清楚为什么就要知道为什么 valueStack.getRoot() 中会有一个 为null的 对象，
也就是要搞清楚valueStack到底是放的什么东西...然后...求分析...
续：
在论坛问了一下，没有结果，冷静分析了一下，其他的页面都可以正常，唯独这一个页面不可以，由此断定出问题的地方在action里面，
然后发现这么一段代码：ActionContext.getContext().getValueStack().push(member);
这就是问题所在，可想而知当时的root里面的null从何而来，于是加一个if(member != null){}，问题也算是解决了。
具体不知道是谁添加的，用来干什么的，所以加一个if判断一下，估计是页面上用到，只是有点不符合我们代码的一贯风格。
