在 h:dataTable 中更新后未反映在 JPA 实体中的更改 [英] Changes not reflected in JPA entities after updating in h:dataTable
本文介绍了在 h:dataTable 中更新后未反映在 JPA 实体中的更改的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我正在使用 Eclipse 和 Glassfish 3.0.尽管我以前做过类似的事情，但对这项技术还是很陌生.非常简单，真正得到了一个绑定到支持 bean 的数据表.添加方法和删除方法我已经介绍过 - 问题在于我正在调用的更新方法.我似乎看不到组件 (HtmlInputText) 中的更改，别介意将数据传回表.
I am working with Eclipse and Glassfish 3.0. Pretty new to this technology although I have done similar things before. Very simple really got a datatable bound to a backing bean. Add methods and remove methods i have covered - the problem lies with the update method I am calling. I cannot seem to see the changes being picked up in the component (HtmlInputText) never mind passing the data back to the table.
我的数据表代码如下(和jsf页面)
My code for the data table is below (and the jsf page)
<html xmlns="http://www.w3.org/1999/xhtml"
xmlns:ui="http://java.sun.com/jsf/facelets"
xmlns:h="http://java.sun.com/jsf/html"
xmlns:f="http://java.sun.com/jsf/core">
<f:loadBundle basename="resources.application" var="msg"/>
<head>
<title><h:outputText value="#{msg.welcomeTitle}" /></title>
</head>
<body>
<h:form id="mainform">
<h:dataTable var="row" border="0" value="#{beanCategory.collection}" binding="#{beanCategory.datatable}">
<f:facet name="header">
<h:outputText value="Categories"/>
</f:facet>
<h:column>
<f:facet name="header">
<h:outputText value="Description"/>
</f:facet>
<h:inputText id="input1" value="#{row.description}" valueChangeListener="#{row.inputChanged}"/>
</h:column>
<h:column>
<f:facet name="header">
<h:outputText value="Id"/>
</f:facet>
<h:outputText id="id" value="#{row.id}"/>
</h:column>
<h:column>
<h:commandButton value="Delete" type="submit" action="#{beanCategory.remove}">
<f:setPropertyActionListener target="#{beanCategory.selectedcategory}" value="#{row}"/>
</h:commandButton>
<h:commandButton value="Save" action="#{beanCategory.update}"
>
<f:setPropertyActionListener
target="#{beanCategory.selectedcategory}" value="#{row}" />
</h:commandButton>
</h:column>
</h:dataTable>
<h:inputText id="text1"></h:inputText> <h:commandButton action="#{beanCategory.addCategory}" value="Add" type="submit" id="submitbutton">
</h:commandButton>
<br/><br/>
Messages
<h:messages></h:messages><br /><br />
</h:form>
</body>
</html>
支持 Bean 在这里
Backing Bean is here
package net.bssuk.timesheets.controller;
import java.io.Serializable;
import java.util.List;
import javax.faces.component.UIInput;
import javax.faces.component.html.HtmlDataTable;
import javax.faces.context.FacesContext;
import javax.persistence.*;
import net.bssuk.timesheets.model.Category;
@javax.inject.Named("beanCategory")
@javax.enterprise.context.SessionScoped
public class BeanCategory implements Serializable {
private List<Category> collection;
private EntityManagerFactory emf;
private EntityManager em;
private int selectedid;
private Category selectedcategory;
private HtmlDataTable datatable;
private static final long serialVersionUID = 1L;
public BeanCategory() {
// TODO Auto-generated constructor stub
System.out.println("Bean Constructor");
}
public String addCategory() {
try {
this.emf = Persistence.createEntityManagerFactory("timesheets1");
System.out.println("Changed - Now attempting to add");
System.out.println("Ready to do cateogory");
Category category = new Category();
FacesContext context = FacesContext.getCurrentInstance();
UIInput input = (UIInput) context.getViewRoot().findComponent(
"mainform:text1");
String value = input.getValue().toString();
if (value != null) {
category.setDescription(input.getValue().toString());
} else {
category.setDescription("Was null");
}
this.em = this.emf.createEntityManager();
EntityTransaction tx = em.getTransaction();
tx.begin();
em.persist(category);
tx.commit();
em.close();
emf.close();
// return "index.xhtml";
} catch (Exception e) {
e.printStackTrace();
}
return "return.html";
}
public String remove() {
try {
this.emf = Persistence.createEntityManagerFactory("timesheets1");
System.out.println("Getting Collection");
this.em = this.emf.createEntityManager();
FacesContext context = FacesContext.getCurrentInstance();
System.out.println("Number found is " + this.selectedid);
if (selectedcategory != null) {
System.out.println("removing "+selectedcategory.getId()+" - " +selectedcategory.getDescription());
EntityTransaction tx = em.getTransaction();
tx.begin();
System.out.println("Merging..");
this.em.merge(selectedcategory);
System.out.println("removing...");
this.em.remove(selectedcategory);
tx.commit();
em.close();
emf.close();
}else{
System.out.println("Not found");
}
return "index.xhtml";
} catch (Exception e) {
e.printStackTrace();
return "index.xhtml";
}
}
public String update() {
try {
this.emf = Persistence.createEntityManagerFactory("timesheets1");
System.out.println("Update Getting Collection");
Category category = (Category) getDatatable().getRowData();
FacesContext context = FacesContext.getCurrentInstance();
System.out.println("PHASE ID="+context.getCurrentPhaseId().toString());
if (category != null) {
// DESCRIPTION VALUE BELOW IS ALWAYS OLD VALUE (IE DATA IN DATABASE)
System.out.println("updating "+category.getId()+" - " +category.getDescription());
this.em = this.emf.createEntityManager();
EntityTransaction tx = em.getTransaction();
tx.begin();
em.merge(category);
tx.commit();
em.close();
emf.close();
}else{
System.out.println("Not found");
}
return "index.xhtml";
} catch (Exception e) {
e.printStackTrace();
return "";
}
}
public void setCollection(List<Category> collection) {
this.collection = collection;
}
public List<Category> getCollection() {
// this.emf=Persistence.createEntityManagerFactory("timesheets1");
// System.out.println("Getting Collection");
try {
this.emf = Persistence.createEntityManagerFactory("timesheets1");
this.em = this.emf.createEntityManager();
Query query = this.em.createNamedQuery("findAll");
this.collection = query.getResultList();
return this.collection;
} catch (Exception e) {
e.printStackTrace();
return null;
}
}
public void setSelectedid(int id) {
this.selectedid=id;
}
public void setSelectedcategory(Category selectedcategory) {
this.selectedcategory = selectedcategory;
}
public HtmlDataTable getDatatable() {
return datatable;
}
public void setDatatable(HtmlDataTable datatable) {
this.datatable = datatable;
}
public Category getSelectedcategory() {
return selectedcategory;
}
}
我的 JPA 映射实体在这里
My Mapped entity for JPA is here
package net.bssuk.timesheets.model;
import java.io.Serializable;
import javax.persistence.*;
/**
* The persistent class for the CATEGORIES database table.
*
*/
@Entity
@Table(name="CATEGORIES")
@NamedQuery(name="findAll", query = "SELECT c from Category c")
public class Category implements Serializable {
private static final long serialVersionUID = 1L;
private String description;
@Id
@GeneratedValue(strategy=GenerationType.IDENTITY)
private int id;
public Category() {
}
public String getDescription() {
return this.description;
}
public void setDescription(String description) {
this.description = description;
}
public int getId() {
return this.id;
}
public void setId(int id) {
this.id = id;
}
}
好的 - 更新了我的代码以遵循示例.我尝试将 EJB 合并到场景中，如下所示
OK - Updated my code to follow example. I have tried to incorporate an EJB into the scenario as follows
package net.bssuk.timesheets.ejb;
import java.util.List;
import javax.ejb.Stateless;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
import javax.persistence.Query;
import net.bssuk.timesheets.model.Category;
@Stateless
public class CategoryEJB implements CategoryEJBRemote {
@PersistenceContext(unitName="timesheets1")
private EntityManager em;
@Override
public List<Category> findCategories() {
// TODO Auto-generated method stub
System.out.println("find categories");
Query query = em.createNamedQuery("findAll");
return query.getResultList();
}
@Override
public Category createCategory(Category category) {
// TODO Auto-generated method stub
em.persist(category);
return category;
}
@Override
public Category udpateCategory(Category category) {
// TODO Auto-generated method stub
return em.merge(category);
}
@Override
public void deleteCategory(Category category) {
// TODO Auto-generated method stub
em.remove(em.merge(category));
}
}
我的 EJB 在下面
package net.bssuk.timesheets.ejb;
import java.util.List;
import javax.ejb.Stateless;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
import javax.persistence.Query;
import net.bssuk.timesheets.model.Category;
@Stateless
public class CategoryEJB implements CategoryEJBRemote {
@PersistenceContext(unitName="timesheets1")
private EntityManager em;
@Override
public List<Category> findCategories() {
// TODO Auto-generated method stub
System.out.println("find categories");
Query query = em.createNamedQuery("findAll");
return query.getResultList();
}
@Override
public Category createCategory(Category category) {
// TODO Auto-generated method stub
em.persist(category);
return category;
}
@Override
public Category udpateCategory(Category category) {
// TODO Auto-generated method stub
return em.merge(category);
}
@Override
public void deleteCategory(Category category) {
// TODO Auto-generated method stub
em.remove(em.merge(category));
}
}
有人可以建议这种看起来好吗?或者我完全失去了它的情节！
Can anyone suggest if this sort of looks ok? Or have I completely lost the plot with it!
推荐答案
看，
<h:dataTable var="row" border="0" value="#{beanCategory.collection}" binding="#{beanCategory.datatable}">
和
public List<Category> getCollection() {
// this.emf=Persistence.createEntityManagerFactory("timesheets1");
// System.out.println("Getting Collection");
try {
this.emf = Persistence.createEntityManagerFactory("timesheets1");
this.em = this.emf.createEntityManager();
Query query = this.em.createNamedQuery("findAll");
this.collection = query.getResultList();
return this.collection;
} catch (Exception e) {
e.printStackTrace();
return null;
}
}
您正在 getter 方法中加载列表.这是一个非常糟糕的主意.一个 getter 应该只是一个对 bean 属性的访问点，而不是做一些商业工作.在 bean 的生命周期中可以多次调用 getter.DB 将在每次调用时被命中，并且在表单提交期间由 JSF 更新的本地 collection 属性将在稍后再次被覆盖.这毫无意义.
You're loading the list inside a getter method. This is a very bad idea. A getter should solely be an access point to the bean property, not to do some business job. A getter can be called multiple times during bean's life. The DB will be hit on every call and the local collection property which was been updated by JSF during form submit will be overwritten again at a later point. This makes no sense.
在(后)构造函数方法或动作(侦听器)方法中完成业务工作.绝对不在吸气剂中.这是一个带有一些代码改进的最小启动示例:
Do the business job in the (post)constructor method or action(listener) methods. Definitely not in a getter. Here's a minimum kickoff example with some code improvements:
<h:dataTable value="#{bean.categories}" var="category">
<h:column>
<h:inputText value="#{category.description}" />
</h:column>
<h:column>
<h:outputText value="#{category.id}" />
</h:column>
<h:column>
<h:commandButton value="Delete" action="#{bean.delete(category)}" />
<h:commandButton value="Save" action="#{bean.update(category)}" />
</h:column>
</h:dataTable>
<h:inputText value="#{bean.newCategory.description}" />
<h:commandButton value="Add" action="#{bean.add}" />
(注意，EL 2.2(Servlet 3.0的一部分)开始支持在EL中传递参数，Glassfish 3是一个Servlet 3.0容器，所以当web.xml时它肯定支持它正确声明符合 Servlet 3.0 规范)
(note that passing arguments in EL is supported since EL 2.2 (part of Servlet 3.0), Glassfish 3 is a Servlet 3.0 container, so it should definitely support it when web.xml is properly declared conform Servlet 3.0 spec)
与
@ManagedBean
@ViewScoped // Definitely don't use session scoped. I'm not sure about CDI approach, so here's JSF example.
public class Bean {
private List<Category> categories;
private Category newCategory;
@EJB
private CategoryService categoryService;
@PostConstruct
public void init() {
categories = categoryService.list();
newCategory = new Category();
}
public void add() {
categoryService.add(newCategory);
init();
}
public void delete(Category category) {
categoryService.delete(category);
init();
}
public void update(Category category) {
categoryService.update(category);
init();
}
public List<Category> getCategories() {
return categories;
}
public Category getNewCategory() {
return newCategory;
}
}
应该是这样.另见:
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