我有一個用戶下拉列表,我可以分配給WorkOrder。用戶到WorkOrder是OneToMany關係。問題是如何將NULL值分配給用戶Id?如果我不將它設置爲NULL,它可以正常工作,我可以從列表中分配任何名稱。如何在我的下拉列表中將值設置爲NULL?
如果我用這個代碼,並挑選NULL <form:option value="${null}" label="null" />
在我的jsp我得到一個錯誤:
Failed to convert property value of type java.lang.String to required type int for property user.id; nested exception is java.lang.NumberFormatException: For input string: ""
這裏是我的WorkorderDAOImpl
@Override
public void saveWorkOrder(WorkOrder theWorkOrder) {
// get the current hibernate session
Session currentSession = sessionFactory.getCurrentSession();
User user = theWorkOrder.getUser();
System.out.println("workorder: " + theWorkOrder);
System.out.println("user: " + user);
//save/update the work order
currentSession.saveOrUpdate(theWorkOrder);
}
我的工作單,form.jsp我省略一些標籤
<form:errors path="workorder.*"/>
<form:errors path="user.*"/>
<form:form action="saveWorkOrder" modelAttribute="workorder" method="POST">
<!-- need to assotiate the data with workorder id -->
<form:hidden path="id"/>
<table>
<tbody>
<tr>
<td><label>User name:</label></td>
<td><form:input path="user.userName"/></td>
</tr>
<tr>
<td><label>User:</label></td>
<td><form:select path="user.id">
<form:option value="${null}" label="null" />
<form:options items="${users}"
itemLabel="userName" itemValue="id"
/>
</form:select>