我想从 jsp 页面中的“表单”下拉“选择”列表中获取选定值到表单的操作类中定义的变量中，其中“选择”下拉列表本身是从列中动态获取的数据库表 'Category' 的名称'和列表 'categoryList' 是在另一个动作类中定义的。
获取所选值（即类别名称）后，我想获取表“类别”的主键“cid”。Category 的列是：id，name
在检索到类别的“cid”后，我想在另一个表“问题”的“cid”列中填写这个 cid。
我正在使用struts2和hibernate。
我的列是“名称”，表是“类别”我已经进行了映射配置和 bean 类。
我生成列表的动作类代码：
public class FindCategory extends ActionSupport {
private List<Category> categoryList = new ArrayList<Category>();
@Override
public String execute() throws Exception {
Session session = null;
try {
session = HibernateUtil.getSessionFactory().getCurrentSession();
session.beginTransaction();
this.categoryList = (List<Category>) session.createQuery("from Category").list();
if (this.categoryList.isEmpty()) {
this.addActionError("Sorry.. No category Available. Try again Later.!");
return ERROR;
}
session.getTransaction().commit();
} catch (Exception e) {
this.addActionError("Oops. An Error Encountered...!");
return ERROR;
}
return SUCCESS;
}
public List<Category> getCategoryList() {
return categoryList;
}
public void setCategoryList(List<Category> categoryList) {
this.categoryList = categoryList;
}
}
jsp页面的“形式”中的代码：
<s:form action="okadddqs" method="post" cssClass="text">
<input type="hidden" name="email" value="goods.ramesh@gmail.com"/>
<s:select label="Select Category :" name="name" list="categoryList" listkey="name" listValue="name"/> //Here the list is generated
<s:textarea label="Your Question " cols="40" rows="5" name="body"/>
<s:textfield name="op1" label="Option 1 :"/>
<s:textfield name="op2" label="Option 2 :"/>
<s:textfield name="op3" label="Option 3 :"/>
<s:textfield name="op4" label="Option 4 :"/>
<s:textfield name="op5" label="Option 5 :"/>
<s:select label="Correct Option :"
name="opc"
list="#@java.util.LinkedHashMap@{'1':'One',
'2':'Two','3':'Three','4':'Four','5':'Five'}"/>
<s:submit value="Update Daily Question"/>
</s:form>
我提交新问题类的操作：
package com.rambo.action;
import beans.Category;
import beans.Question;
import beans.Users;
import com.opensymphony.xwork2.ActionSupport;
import java.util.ArrayList;
import java.util.List;
import java.util.StringTokenizer;
import javax.faces.bean.ManagedBean;
import javax.faces.bean.SessionScoped;
import org.hibernate.Session;
/**
*
* @author ROMO
*/
@ManagedBean
@SessionScoped
public class NewQuestion extends ActionSupport {
private String cname;
private List<Category> cl = new ArrayList<Category>();
public List<Category> getCl() {
return cl;
}
public void setCl(List<Category> cl) {
this.cl = cl;
}
@Override
public String execute() throws Exception {
Session session = null;
int c;
//c store the cid of the selected Category name from drop down list.
try {
session = HibernateUtil.getSessionFactory().getCurrentSession();
session.beginTransaction();
cl = (List<Category>) session.createQuery("from Category c where c.name = '" + getName() + "'");
if (!cl.isEmpty()) {
c = cl.get(0).getCid();
} else {
this.addActionError("Oops. Sorry No Category Available.");
session.close();
return ERROR;
}
u = new Question();
u.setCid(c);
u.setCname(getName());
session.save(u);
session.getTransaction().commit();
} catch (Exception e) {
this.addActionError("Oops. An Error Encountered...! Email address already registered. Try with your new email address.");
session.close();
return ERROR;
}
return SUCCESS;
}
@Override
public void validate() {
if ("".equals(getEmail()) || getEmail() == null ) {
this.addActionError("All Fields are Compulsory to input..!");
} else if (getEmail().indexOf("@") < 0 || getEmail().indexOf(",") > 0 || getEmail().indexOf(".") < 0) {
this.addActionError("Please Input a valid email address.");
}
}
}
Category.hbm.xml 中的映射：
<property name="name" type="string">
<column name="NAME" length="20" not-null="true" />
</property>
bean "Category.java" 的 getter 和 setter：
public String getName() {
return this.name;
}
public void setName(String name) {
this.name = name;
}
我的 glassfish 服务器显示错误为：
org.apache.jasper.JasperException: tag 'select', field 'list', name 'cname': The requested list key 'categoryList' could not be resolved as a collection/array/map/enumeration/iterator type. Example: people or people.{name} - [unknown location]
root cause tag 'select', field 'list', name 'cname': The requested list key 'categoryList' could not be resolved as a collection/array/map/enumeration/iterator type. Example: people or people.{name} - [unknown location]
有人可以指出可能是什么错误..？提前致谢。