HTTP Status 500 - 问题求解决！！！

Question

Apache 用的是6.0.14版本，struts 1.2 架构 在做登录的页面跳转时出现这个错误 
HTTP Status 500 - --------------------------------------------------------------------------------type Exception reportmessage description The server encountered an internal error () that prevented it from fulfilling this request.exception javax.servlet.ServletException: java.lang.NullPointerException
org.apache.struts.action.RequestProcessor.processException(RequestProcessor.java:535)
org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:433)
org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:236)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1196)
org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:432)
javax.servlet.http.HttpServlet.service(HttpServlet.java:710)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
root cause java.lang.NullPointerException
com.action.Manager.managerLogin(Manager.java:35)
com.action.Manager.execute(Manager.java:24)
org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:431)
org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:236)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1196)
org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:432)
javax.servlet.http.HttpServlet.service(HttpServlet.java:710)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
note The full stack trace of the root cause is available in the Apache Tomcat/6.0.14 logs.

Answer 1

root cause java.lang.NullPointerException
com.action.Manager.managerLogin(Manager.java:35)
com.action.Manager.execute(Manager.java:24)
具体看看com.action.Manager.managerLogin(Manager.java:35)
中的35行出现空指针异常了...

Answer 2

空指针异常....自己好好检查一下com.action.Manager.managerLogin，或者把它贴出来

Answer 3

红色标注的为35行
public ActionForward managerLogin(ActionMapping mapping, ActionForm form,
HttpServletRequest request, HttpServletResponse response) {
ManagerForm managerForm = (ManagerForm) form;
managerForm.setName(managerForm.getName());
managerForm.setPwd(managerForm.getPwd());
int ret = managerDAO.checkManager(managerForm);
System.out.print("验证结果ret的值:" + ret);
if (ret == 1) {
HttpSession session = request.getSession();
session.setAttribute("manager", managerForm.getName());
return mapping.findForward("managerLoginok");
} else {
request.setAttribute("error", "您输入的管理员名称或密码错误！");
return mapping.findForward("error");
}
}
}

Answer 4

managerForm.getName()是null
managerForm.getName()==null?"":managerForm.getName();

Answer 5

估计是managerForm 为null吧，单步debug调试看看

Answer 6

检查下managerForm和managerForm.getName()的执行结果，如果form为null，强转成ManagerForm也不会报错的