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我知道這個問題以前可能已經被問過了，但我沒有得到解決我的問題的方法。我有一個varchar（20）categoryID的主鍵列，實體類通過id屬性映射到這個主鍵列。在添加數據時，通過UI輸入一個id值，但在編輯其他字段並通過UI保存時，其拋出異常「IdentifierGenerationException：此類的ids必須在調用save（）之前手動分配：」org.hibernate.id.IdentifierGenerationException：在調用save（）之前，必須手動分配此類的ids：
請看以下代碼：
Category.java
-------------
package com.niit.cakecuisinebe.model;
import java.util.UUID;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.PrePersist;
import javax.persistence.Table;
import org.springframework.stereotype.Component;
@Entity
@Table
@Component
public class Category {
@Id
@Column(name="CATEGORYID")
private String id;
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getDescription() {
return description;
}
public void setDescription(String description) {
this.description = description;
}
@Column(name="CATEGORYNAME")
private String name;
@Column(name="CATEGORYDESCRIPTION")
private String description;
}
CategoryDAOImpl
----------------
package com.niit.cakecuisinebe.dao;
import java.util.List;
import javax.transaction.Transactional;
import org.hibernate.Criteria;
import org.hibernate.Query;
import org.hibernate.SessionFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Repository;
import com.niit.cakecuisinebe.model.Category;
@Repository("categoryDAO")
public class CategoryDAOImpl implements CategoryDAO{
@Autowired
private SessionFactory sessionFactory;
public CategoryDAOImpl(SessionFactory sessionFactory) {
this.sessionFactory = sessionFactory;
}
@Transactional
public List<Category> list()
{
//Logger.debug("calling list");
@SuppressWarnings("unchecked")
List<Category> listCategory = (List<Category>)
sessionFactory.getCurrentSession()
.createCriteria(Category.class)
.setResultTransformer(Criteria.DISTINCT_ROOT_ENTITY).list();
// Logger.debug("calling list");
return listCategory;
}
@Transactional
public Category get(String id) {
// TODO Auto-generated method stub
String hql = "from Category where id=" + "'"+ id +"'";
// from category where id = '101'
Query query = sessionFactory.getCurrentSession().createQuery(hql);
List<Category> listCategory = (List<Category>) query.list();
if (listCategory != null && !listCategory.isEmpty()) {
return listCategory.get(0);
}
return null;
}
@Transactional
public void saveOrUpdate(Category category) {
// TODO Auto-generated method stub
sessionFactory.getCurrentSession().saveOrUpdate(category);
}
@Transactional
public void delete(String id) {
// TODO Auto-generated method stub
Category category = new Category();
category.setId(id);
sessionFactory.getCurrentSession().delete(category);
}
@Transactional
public Category getByName(String name) {
// TODO Auto-generated method stub
String hql = "from Category where name=" + "'"+ name +"'";
Query query = sessionFactory.getCurrentSession().createQuery(hql);
@SuppressWarnings("unchecked")
List<Category> listCategory = (List<Category>) query.list();
if (listCategory != null && !listCategory.isEmpty()) {
return listCategory.get(0);
}
return null;
}
}
CategoryController
--------------------
package com.niit;
import java.util.List;
import java.util.Map;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.log4j.Logger;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.ui.ModelMap;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import com.niit.cakecuisinebe.dao.CategoryDAO;
import com.niit.cakecuisinebe.model.*;
@Controller
public class CategoryController {
protected static Logger logger = Logger.getLogger("CategoryController");
@Autowired
private CategoryDAO categoryDao;
@RequestMapping(value = "/ViewCategory", method = RequestMethod.GET)
public String getCategory(Model model) {
logger.info("entering showAllGreetings");
model.addAttribute("category", new Category());
List<Category> categories = categoryDao.list();
if (!categories.isEmpty()) {
model.addAttribute("categorylist", categories);
}
return "Category";
}
@RequestMapping(value = "/addCategory", method = RequestMethod.POST)
public String addCategory(@ModelAttribute("category") Category category) {
logger.info("entering showAllGreetings");
categoryDao.saveOrUpdate(category);
return "redirect:/ViewCategory";
}
@RequestMapping(value = "edit/addCategory", method = RequestMethod.POST)
public String editCategory(@ModelAttribute("category") Category category) {
logger.info("entering showAllGreetings");
String id=category.getId();
category.setId(id);
categoryDao.saveOrUpdate(category);
return "redirect:/ViewCategory";
}
@RequestMapping(value = "delete/{id}", method = RequestMethod.GET)
public String deleteCategory(@PathVariable("id") String id, ModelMap model) {
logger.info("entering showAllGreetings");
categoryDao.delete(id);
model.addAttribute("{msg}", "Successfully Deleted");
return "redirect:/ViewCategory";
}
@RequestMapping(value = "edit/{id}", method = RequestMethod.GET)
public String showEditCategory(@PathVariable("id") String id, Model model) {
logger.info("entering showAllGreetings");
model.addAttribute("category", this.categoryDao.get(id));
model.addAttribute("categorylist", categoryDao.list());
return "Category";
}
}
<div >
<spring:form method="POST" action="addCategory" modelAttribute="category" align="center">
<table cellpadding="5" cellspacing="5" style="height=45px; width=45px; background-color: pink; padding=10px">
<tr>
<c:choose>
<c:when test="${!empty category.id}">
<td><spring:label path="id"><springtags:message text="CategoryID"></springtags:message></spring:label></td>
<td><spring:input path="id" disabled="true" readonly="true" /></td>
</c:when>
<c:otherwise>
<td><spring:label path="id"><springtags:message text="CategoryID"></springtags:message></spring:label></td>
<td><spring:input path="id" /></td>
</c:otherwise>
</c:choose>
</tr>
<tr>
<td> Category Name:</td>
<td><spring:input path="name" /></td>
</tr>
<tr>
<td> Category Description:</td>
<td><spring:input path="description" /></td>
</tr>
<tr>
<c:if test="${!empty category.id}">
<td> <input type="submit"
value="<springtags:message text="Edit Category"/>" />
</c:if>
</td>
<td><c:if test="${empty category.id}">
<input type="submit" value="<springtags:message text="Add Category"/>" />
</c:if>
</td>
</tr>
</table>
</spring:form>
</div>
<div class="container">
<table class="table table-striped table-bordered table-hover table-condensed">
<caption><h2>Categories</h2></caption>
<thead>
<tr>
<th>Category ID</th>
<th>Category Name</th>
<th>Category Description</th>
<th>Edit</th>
<th>Delete</th>
</tr>
</thead>
<c:if test="${not empty categorylist}" >
<tbody>
<c:forEach items="${categorylist}" var="category">
<tr>
<td>${category.id}</td>
<td>${category.name}</td>
<td>${category.description} </td>
<td><a href="edit/${category.id}">Edit</a> </td>
<td><a href="delete/${category.id}">Delete</a> </td>
</tr>
</c:forEach>
</tbody>
</c:if>
<c:if test="${empty categorylist}" >
There are no category yet.
</c:if>
</tr>
</table>
</div>
<%@ include file="footer.jsp"%>
</body>
</html>
請幫助套牢此爲最近兩天
'System.out.println（category.getId（））;'in Controller - 輸出是什麼？ –
試圖檢查ID是否被提取，但它是空的我是新的春季和冬眠，我無法完成它請幫助 –
這是控制器的方法，給出了例外？ * editCategory？* * addCategory *工作正常？ – amicoderozer