Spring 2与JPA集成教程：从零开始创建企业应用

需积分: 0 175 浏览量更新于2024-08-02 收藏 808KB PDF 举报

本篇文章主要介绍了Spring 2框架与Java Persistence API (JPA) 的结合，旨在帮助初学者了解如何利用Spring 2的特性来构建高效且易于维护的服务器端Java应用程序。随着Java 2 Enterprise Edition (J2EE)平台的传统地位被逐渐取代，Spring 2的出现为开发者提供了一种轻量级的替代方案，特别是通过其对JPA的集成，这在EJB 3.0规范中扮演了核心角色。在文章的第一部分，作者强调了使用Spring 2进行开发的优势，它使得即使是新手开发者也能轻松创建服务器应用。Spring 2简化了开发流程，提供了众多功能，如数据库连接管理、池化等，这些在过去往往依赖于复杂且庞大的J2EE平台。在教程中，读者将学习如何从头开始使用Spring 2和JPA进行应用程序开发。首先，你需要熟悉Spring 2的基本概念，包括依赖注入、面向切面编程(AOP)等核心原则。同时，了解JPA的基础，包括其实体(Entity)、持久化上下文(PersistenceContext)和持久化会话(PersistenceSession)等概念。文章接下来会引导你配置Spring容器，设置数据源和事务管理器，以便与JPA集成。这包括如何在Spring配置文件中声明JPA实体、数据访问策略以及如何定义JPA实体的Repository接口，这些接口通常用于实现CRUD操作。在实际操作中，作者可能会提供一个使用Eclipse和DB2 Express-C的示例项目，演示如何编写并运行Spring Boot应用，其中包含创建、读取、更新和删除数据的基本步骤。通过这个示例，读者可以了解到如何在Spring 2的上下文中使用JPA进行持久化操作，并学会处理可能遇到的错误和异常。此外，文章还可能涵盖如何使用Spring Data JPA，这是一个基于Spring框架的高级JPA客户端库，它简化了数据访问层的编码工作。这部分内容可能包括动态查询、复杂查询构建、分页和缓存优化等内容。这篇教程将为想要利用Spring 2与JPA结合进行开发的开发者提供实用的指南，使他们能够快速上手并构建出高效、可维护的Java服务器应用。无论是对现有J2EE开发者还是想尝试新技术的开发者，都将从中受益匪浅。

Listing 2. Constructors for the Employee POJO

public Employee(String empno, String firstName, String midInitial, String lastName,

String phoneNumber, String job, int educationLevel, char sex, double salary,

double bonus, double commission, Address addr, Date hiredate, Date birthdate) {

this.empno = empno;

this.firstName = firstName;

this.midInitial = midInitial;

this.lastName = lastName;

this.phoneNumber = phoneNumber;

this.job = job;

this.educationLevel = educationLevel;

this.sex = sex;

this.salary = salary;

this.bonus = bonus;

this.commission = commission;

this.addr = addr;

this.hiredate = hiredate;

this.birthdate = birthdate;

}

public Employee() {}

You need to add the trivial constructor shown in Listing 2 because you use it later in

the unit-test stage. This completes the coding for the Employee business object.

The missing empid field

You may notice that the empid field is missing from the constructor in Listing 2. This

field is used later to contain a JPA-generated primary key associated with an

Employee instance. This key is managed by JPA and should not be modified by the

application. You should now remove the setter method, setEmpid(), from the

source code.

Coding the Address POJO

An Employee object references an Address object. The Address object also

needs to be saved whenever an Employee object is saved to the database.

The code for the Address object is shown in Listing 3, including getters, setters,

and constructors:

Listing 3. Code for the Address POJO

package com.ibm.dw.spring2;

public class Address {

private long id;

private int number;

private String street;

developerWorks® ibm.com/developerWorks

Introduction to Spring 2 and JPA

// find an employee by his name

public List<Employee> findByEmployeeLastName(String lastName);

// find an employees living on a street

public List<Employee> findByAddressStreetName(String streetName);

// find an employee by the internal unique id

public Employee findById(long id);

// find employee over a certain salary

public List<Employee> findEmployeeWithSalaryOver(double sal);

// find employee with a certain commission income

public List<Employee> findEmployeeWithCommissionOver(double comm);

}

Note that in Listing 4, the code is a literally direct translation of the required

operations list from the domain analysis. This interface contains no Spring-specific

coding. You know what you need to do with the objects in this interface but so far,

you don't have a clue how to do it. You'll see how to implement the methods in this

interface very shortly, but first: POJO unit tests.

Testing business objects outside of any container

After coding the independent POJOs and services in your domain model, you can

write unit tests for the POJOs. Up to this point, you still haven't performed any

Spring-specific steps. In fact, you could use the tested POJOs that you end up with

in other applications (or other parts of the same application) without change.

Listing 5 shows POJOUnitTest.java. This is a JUnit test case that tests the

Employee and Address POJOs.

Listing 5. Independent unit test for employee and address POJOs

package com.ibm.dw.spring2;

import java.text.SimpleDateFormat;

import java.util.Date;

import junit.framework.TestCase;

public class POJOUnitTest extends TestCase {

private Employee emp1, emp2;

private Address addr1, addr2;

protected void setUp() throws Exception {

addr1 = new Address(10, "Walker Street");

addr2 = new Address();

addr2.setNumber(20);

addr2.setStreet("Walker Street");

emp1 = new Employee("0001", "Joe", "R","Smith",

"4853", "Engineer", 3, 'M',

developerWorks® ibm.com/developerWorks

Introduction to Spring 2 and JPA

剩余66页未读，继续阅读

chenjianlong114

粉丝: 0
资源: 1

Spring 2与JPA集成教程：从零开始创建企业应用

Spring Data JPA中文文档[1.4.3]_springdatajpa_erlang_waitxpf_

Spring Data JPA 笔记

spring-jpa:Estudio Spring和JPA

spring-jpa:Curso Alura-Spring Data JPA

SpringDataJPA-Learning:Spring Boot JPA学习项目

Spring Boot JpaRepository知识学习（Spring Data JPA）

spring-k8s-jpa-demo:了解如何将Spring Data JPA与Kubernetes结合使用

springjpa:Spring+ JPA + MySQL的

Spring MVC结合Spring Data JPA实现按条件查询和分页

Spring Data JPA

最新资源