今天用 struts + iBatis 制作一个功能模块中，提交表单网页报错，但是控制台没有报错，郁闷了，寻找出错原因ing

HTTP Status 500 -

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type Exception report

message

description The server encountered an internal error () that prevented it from fulfilling this request.

exception

javax.servlet.ServletException: BeanUtils.populate
org.apache.struts.util.RequestUtils.populate(RequestUtils.java:1254)
org.apache.struts.action.RequestProcessor.processPopulate(RequestProcessor.java:821)
org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:254)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1435)
org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:523)
javax.servlet.http.HttpServlet.service(HttpServlet.java:709)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
com.talent.tdp.base.util.SessionValidFilter.doFilter(SessionValidFilter.java:135)

root cause

java.lang.IllegalArgumentException: No bean specified
org.apache.commons.beanutils.PropertyUtils.getPropertyDescriptor(PropertyUtils.java:837)
org.apache.commons.beanutils.BeanUtils.setProperty(BeanUtils.java:934)
org.apache.commons.beanutils.BeanUtils.populate(BeanUtils.java:808)
org.apache.struts.util.RequestUtils.populate(RequestUtils.java:1252)
org.apache.struts.action.RequestProcessor.processPopulate(RequestProcessor.java:821)
org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:254)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1435)
org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:523)
javax.servlet.http.HttpServlet.service(HttpServlet.java:709)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
com.talent.tdp.base.util.SessionValidFilter.doFilter(SessionValidFilter.java:135)

note The full stack trace of the root cause is available in the Apache Tomcat/5.0.30 logs.

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Apache Tomcat/5.0.30

晕，原来是 form 没有构造函数：

修改前：
public CarBorrowForm() {
}

修正后：
public CarBorrowForm() {
if (this.getVo() == null)
this.setVo(new CarBorrowVO());
}

得保证 form 的 vo 不能为空！