我正在开发一个简单的应用程序,其中数据库中的用户记录显示在primefaces数据表中,用户可以编辑或删除记录。 这是jsf文件
<h:form>
<p:dataTable var="user" value="#{userBean.users}" >
<p:column headerText="username">
<h:inputText value="#{user.username}" rendered="#{userBean.editable}" />
<h:outputText value="#{user.username}" rendered="#{not userBean.editable}" />
<!--<h:outputText value="#{user.username}" />-->
</p:column>
<p:column headerText="edit">
<h:commandLink value="Edit" action="#{userBean.editAction(index)}" rendered="#{not userBean.editable}" />
</p:column>
<p:column headerText="save">
<p:commandButton value="Save" id="save" disabled="false" action="#{userBean.saveAction(user)}"/>
</p:column>
<p:column headerText="delete">
<p:commandButton value="Delete" id="delete" disabled="false" action="#{userBean.deleteAction(user)}"/>
</p:column>
</p:dataTable>
</h:form>
这是我在bean中调用的保存和更新操作方法
public String saveAction(User user) {
this.setEditable(false);
DB db = new DB();
db.updateUser(user);
return "editSuccess";
}
public String deleteAction(User user) {
DB db = new DB();
db.deleteUser(user);
return "editSuccess";
}
以及dao图层中的方法
EntityManagerFactory emf = javax.persistence.Persistence.createEntityManagerFactory("RegisterationFormJPAPU");
EntityManager em = emf.createEntityManager();
public void updateUser(User user) {
Query query = em.createQuery("update User set username = :uname where username = :uname");
query.setParameter("uname", user.getUsername());
query.executeUpdate();
}
public void deleteUser(User user) {
Query query = em.createQuery("delete from User where username = :uname");
query.setParameter("uname", user.getUsername());
query.executeUpdate();
}
但是当我按下编辑链接或删除按钮时,会出现此错误
Severe: javax.faces.el.EvaluationException: javax.persistence.TransactionRequiredException:
Exception Description: No transaction is currently active
有人会告诉我问题出在哪里。
答案 0 :(得分:4)
高兴尝试这个:
em.getTransaction().begin();
Query query = em.createQuery("update User set username = :uname where username = :uname");
query.setParameter("uname", user.getUsername());
query.executeUpdate();
em.getTransaction().commit();
如果这可以解决您的问题,请告诉我。
答案 1 :(得分:0)
You cannot explicitly call the transaction in this context. The commit is managed by the server automatically.
You can simply use:
user.setName("NEW USER NAME");
modifyUser(user);
public void modifyUser(User user) {
em.merge(user)}