开发环境搭建

引入 Maven 依赖

<!-- Spring data jpa -->
<dependency>
    <groupId>org.springframework.data</groupId>
    <artifactId>spring-data-jpa</artifactId>
    <version>1.8.0.RELEASE</version>
</dependency>
<dependency>
    <groupId>org.hibernate</groupId>
    <artifactId>hibernate-core</artifactId>
    <version>4.3.6.Final</version>
</dependency>

创建 beans-new.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:tx="http://www.springframework.org/schema/tx"
       xmlns:jpa="http://www.springframework.org/schema/data/jpa"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
       http://www.springframework.org/schema/beans/spring-beans.xsd
       http://www.springframework.org/schema/tx 
       http://www.springframework.org/schema/tx/spring-tx.xsd
       http://www.springframework.org/schema/data/jpa
       http://www.springframework.org/schema/data/jpa/spring-jpa.xsd
       http://www.springframework.org/schema/context
       http://www.springframework.org/schema/context/spring-context.xsd">

    <!-- 1 配置数据源 -->
    <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <property name="driverClassName" value="com.mysql.jdbc.Driver"/>
        <property name="username" value="root"/>
        <property name="password" value="weilai"/>
        <property name="url" value="jdbc:mysql:///spring_data?useSSL=false"/>
    </bean>

    <!-- 2 配置EntityManagerFactory -->
    <bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
        <property name="dataSource" ref="dataSource"/>

        <property name="jpaVendorAdapter">
            <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter"/>
        </property>

        <property name="packagesToScan" value="com.imooc"/>

        <property name="jpaProperties">
            <props>
                <prop key="hibernate.ejb.naming_strategy">org.hibernate.cfg.ImprovedNamingStrategy</prop>
                <prop key="hibernate.dialect">org.hibernate.dialect.MySQL5InnoDBDialect</prop>
                <prop key="hibernate.show_sql">true</prop>
                <prop key="hibernate.format_sql">true</prop>
                <prop key="hibernate.hbm2ddl.auto">update</prop>
            </props>
        </property>
    </bean>

    <!-- 3 配置事务管理器 -->
    <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
        <property name="entityManagerFactory" ref="entityManagerFactory"/>
    </bean>

    <!-- 4 支持注解的事务 -->
    <tx:annotation-driven transaction-manager="transactionManager"/>

    <!-- 5 配置 Spring Data -->
    <jpa:repositories base-package="com.imooc" entity-manager-factory-ref="entityManagerFactory"/>

    <context:component-scan base-package="com.imooc"/>

</beans>

Spring Data JPA HelloWorld 开发

Repository

• Repository 继承
• Repository Definition 注解
• Repository Query Specifications 查询规则
• Query Annotation 原生查询注解
• update/delete/transaction 更新、删除、事务

Repository Hierarchy

• CrudRepository 增删改查
• PagingAndSortingRepository 分页和排序
• JpaRepository JPA
• JpaSpecificationExecutor JPA 特殊功能

JPA 实体

package com.imooc.domain;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;

/**
 * 雇员: 先开发实体类，自动生成数据表
 *
 * @author weilai
 * @version 1.0.0 2018/8/23
 */
@Entity
public class Employee {

    private Integer id;

    private String name;

    private Integer age;

    @Id
    @GeneratedValue
    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    @Column(length = 20, nullable = false)
    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    @Column(nullable = false)
    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }
}

JPA Repository

package com.imooc.repository;

import com.imooc.domain.Employee;
import org.springframework.data.repository.Repository;


/**
 * @author weilai
 * @version 1.0.0 2018/8/23
 */
public interface EmployeeRepository extends Repository<Employee, Integer> {

    public Employee findByName(String name);

}

单元测试

package com.imooc.repository;

import com.imooc.domain.Employee;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import static org.junit.Assert.*;

/**
 * @author weilai
 * @version 1.0.0 2018/8/23
 */
public class EmployeeRepositoryTest {

    private ApplicationContext context = null;
    private EmployeeRepository employeeRepository = null;

    @Before
    public void setUp() {
        context = new ClassPathXmlApplicationContext("beans-new.xml");
        employeeRepository = context.getBean(EmployeeRepository.class);
        System.out.println("setUp");
    }

    @After
    public void tearDown() {
        context = null;
        System.out.println("tearDown");
    }

    @Test
    public void findByName() {
        Employee employee = employeeRepository.findByName("zhangsan");
        System.out.println("ID:" + employee.getId() + ", " +
                "Name:" + employee.getName() + ", " +
                "Age:" + employee.getAge() + "。"
        );
    }
}