ERROR org.apache.struts2.dispatcher.DefaultDispatcherErrorHandler - Exception occurred during processing request: null
java.lang.NullPointerException
at service.impl.StudentsDAOImpl.addStudents(StudentsDAOImpl.java:64) ~[StudentsDAOImpl.class:?]
at action.StudentsAction.add(StudentsAction.java:51) ~[StudentsAction.class:?]
2017-06-19
你可以参考一下：把下面的代码内容，跟你写的做一下对比
一、在StudentsDAOImpl.java中实现添加学生的方法即可
//添加学生
public boolean addStudents(Students s) {
//因为添加的学生是没有学号的，所以我们需要添加一个学号
s.setSid(getNewSid());
Transaction tx = null;
try{
Session session = MyHibernateSessionFactory.getSessionFactory().getCurrentSession();
tx = session.beginTransaction();
session.save(s);
tx.commit();
return true;
}catch(Exception ex){
ex.printStackTrace();
tx.commit();
return false;
}finally{
if(tx != null){
tx = null;
}
}
}二、StudentsAction类中add()方法：
//添加学生
public String add() throws Exception{
Students s = new Students();
s.setSname(request.getParameter("sname"));
s.setGender(request.getParameter("gender"));
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
s.setBirthday(sdf.parse(request.getParameter("birthday")));
s.setAddress(request.getParameter("address"));
StudentsDAO sdao = new StudentsDAOImpl();
sdao.addStudents(s);
return "add_success";
}三、struts.xml
<package name="students" namespace="/students" extends="default">
<action name="*_*" class="action.{1}Action" method="{2}">
<result name="query_success">/students/Students_query_success.jsp</result>
<result name="add_success">/students/Students_add_success.jsp</result>
<result name="modify_success">/students/Students_modify.jsp</result>
<result name="delete_success" type="chain">Students_query</result><!-- chain表示后面链接一个动作,也就是服务器内部转发，它转发的只能是action，而不是一个jsp页面 -->
</action>
</package>四、Students_add.jsp中的form表单
<form name="addForm" action="<%=path%>/students/Students_add.action" method="post"> <table width="400" > <tr> <td width="30%">姓名：</td> <td><input type="text" name="sname" /></td> </tr> <tr> <td>性别：</td> <td><input type="radio" name="gender" value="男" checked="checked"/>男<input type="radio" name="gender" value="女"/>女</td> </tr> <tr> <td>出生日期：</td> <td><input name="birthday" type="text" id="control_date" size="20" maxlength="10" onclick="new Calendar().show(this);" readonly="readonly" /> </td> </tr> <tr> <td>地址：</td> <td><input type="text" name="address" /></td> </tr> <tr> <td colspan="2" align="center"><input class="button" type="submit" value="添加"></td> </tr> </table> </form>
举报
