Question

我需要帮助。我想要的是如何通过名称在数据库中查找对象，还能够编辑和保存对象。

Business Logik

更新员工

public void edit(Long id, Customer editCustomer) {
    try {
        entityTransaction = em.getTransaction();
        em.getTransaction().begin();
        em.merge(editCustomer);
        Customer customer = em.find(Customer.class, id);
        customer.setId(id);
        customer.setFirstName(editCustomer.getFirstName());
        customer.setLastName(editCustomer.getLastName());
        customer.setAddress(editCustomer.getAddress());
        customer.setId(editCustomer.getId());
        em.getTransaction().commit();
    } catch (Exception e) {
        if (em.isOpen())
            em.getTransaction().rollback();
        e.printStackTrace();
    }
}

FindByName

public Customer getCustomerByName（String firstName）{

TypedQuery query = em.createQuery（“SELECT c FROM Customer c WHERE

c.firstName =：firstName“，Customer.class）;

return query.setParameter（“firstName”，firstName）.getSingleResult（）;

}

JSF ManagedBean

public String findByName（）{

    BookstoreManager.getInstance().getCustomerByName(firstName);

    System.out.println("Hello " + customer.getFirstName());

    return "Customer";

}

**Result**

2017-07-02T16：43：13.927 + 0200 |信息：Hello null

XHTML

Answer 1

    **JSF ManagedBean**

        public String findByName(){
                Customer customer=
                BookstoreManager.getInstance().getCustomerByName(firstName);
                System.out.println("Hello " + customer.getFirstName());
                return "Customer";
            }

    **Business Logik**

        public Customer getCustomerByName(String firstName) {
                Customer cus = null;
                try {
                    TypedQuery<Customer> query = em.createQuery("SELECT cus FROM Customer cus WHERE cus.firstName = :firstName",
                            Customer.class);
                    cus = query.setParameter("firstName", firstName).getSingleResult();
                } catch (NoResultException e) {
                }
        System.out.println("Customer"+   ":" + cus.getFirstName());
                return cus;

            }

**xhtml code**

<h:form id="main">

<h:panelGrid  columns="2">
<h:outputText for="firstName"  value="#{texts.firstName}"/>
<p:inputText id="firstName"  value="#{customerBean.firstName}"/>
<p:commandButton value="#{texts.name}"  action="#{customerBean.findByName()}" />

</h:panelGrid>
</h:form>

按名称查找对象，使用JPA编辑对象

1 个答案: