2
我正在使用Eclipse Galileo，我想部署一個簡單的應用程序，使用JPA，GlassFish 2.1和MySQL 5.不幸的是，我找不到GlassFish 2.1的任何教程（僅適用於3.0，但我無法使用它）。如何在Eclipse中配置Servlet以使用JPA項目？
我創建了一個JPA項目，增加了一個MySQL5的連接，並從數據庫中生成一個實體。
的生成JPA類是：
package model;
import java.io.Serializable;
import javax.persistence.*;
@Entity
@Table(name="customer")
public class Customer implements Serializable {
private static final long serialVersionUID = 1L;
@Id
@Column(name="customer_id")
private int customerId;
private String email;
@Column(name="first_name")
private String firstName;
@Column(name="last_name")
private String lastName;
public Customer() {
}
public int getCustomerId() {
return this.customerId;
}
public void setCustomerId(int customerId) {
this.customerId = customerId;
}
public String getEmail() {
return this.email;
}
public void setEmail(String email) {
this.email = email;
}
public String getFirstName() {
return this.firstName;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
public String getLastName() {
return this.lastName;
}
public void setLastName(String lastName) {
this.lastName = lastName;
}
}
而且persistence.xml文件是：
<?xml version="1.0" encoding="UTF-8"?>
<persistence version="1.0" xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd">
<persistence-unit name="JPAProject2">
<class>model.Customer</class>
</persistence-unit>
</persistence>
我創建動態Web項目，並增加了一個新的Servlet類，它看起來像這樣：
package servlet;
import java.io.IOException;
import javax.annotation.Resource;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.PersistenceUnit;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.transaction.UserTransaction;
import model.Customer;
public class JpaDemoServlet2 extends HttpServlet
{
private static final long serialVersionUID = 1L;
@PersistenceUnit
private EntityManagerFactory entityManagerFactory;
@Resource
private UserTransaction userTransaction;
public JpaDemoServlet2()
{
super();
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
{
EntityManager entityManager =
entityManagerFactory.createEntityManager();
Customer customer = new Customer();
customer.setCustomerId(3);
customer.setFirstName("Smith");
customer.setLastName("John");
customer.setEmail("[email protected]");
try
{
userTransaction.begin();
entityManager.persist(customer);
userTransaction.commit();
}
catch(Exception ex)
{
response.sendError(1, ex.getMessage());
}
}
}
我在servlet項目的屬性中添加了Project References和Module Dependencie s爲JPA項目。是否有任何其他配置設置必須完成？ 到目前爲止，我能夠發佈Servlet，但不幸的是，我無法運行它。 http://localhost:4848/ServletProject2，我收到'Hello，World！'消息，但如果我想訪問http://localhost:4848/ServletProject2/JpaDemoServlet2我得到這個異常：
Exception [TOPLINK-4002] (Oracle TopLink Essentials - 2.1 (Build b60e-fcs (12/23/2008))): oracle.toplink.essentials.exceptions.DatabaseException
Internal Exception: java.sql.SQLException: Error in allocating a connection. Cause: Connection could not be allocated because: java.net.ConnectException : Error connecting to server localhost on port 1527 with message Connection refused: connect.
Error Code: 0
有什麼我失蹤？