SpringData JPA快速入门

创建项目，添加依赖

<properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <project.hibernate.version>5.0.7.Final</project.hibernate.version>
</properties>

<dependencies>
    <!-- junit -->
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.12</version>
        <scope>test</scope>
    </dependency>

    <!-- hibernate对jpa的支持包 -->
    <dependency>
        <groupId>org.hibernate</groupId>
        <artifactId>hibernate-entitymanager</artifactId>
        <version>${project.hibernate.version}</version>
    </dependency>

    <!-- c3p0 -->
    <dependency>
        <groupId>org.hibernate</groupId>
        <artifactId>hibernate-c3p0</artifactId>
        <version>${project.hibernate.version}</version>
    </dependency>

    <!-- log日志 -->
    <dependency>
        <groupId>log4j</groupId>
        <artifactId>log4j</artifactId>
        <version>1.2.17</version>
    </dependency>

    <!-- Mysql and MariaDB -->
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>5.1.6</version>
    </dependency>
</dependencies>

在resources文件夹下创建文件夹META-INF

然后在META-INF下创建persistence.xml 并进行配置

<?xml version="1.0" encoding="UTF-8"?>
<persistence 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_2_0.xsd"
             version="2.0">

<!--配置持久化单元
        name：持久化单元名称
        transaction-type：事务类型
             RESOURCE_LOCAL：本地事务管理
             JTA：分布式事务管理 -->
    <persistence-unit name="myJpa" transaction-type="RESOURCE_LOCAL">
        <!--配置JPA规范的服务提供商 -->
        <provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>
        <properties>
            <!-- 数据库驱动 -->
            <property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver" />
            <!-- 数据库地址 -->
            <property name="javax.persistence.jdbc.url" value="jdbc:mysql://localhost:3306/jpa" />
            <!-- 数据库用户名 -->
            <property name="javax.persistence.jdbc.user" value="root" />
            <!-- 数据库密码 -->
            <property name="javax.persistence.jdbc.password" value="root" />

            <!--jpa提供者的可选配置：我们的JPA规范的提供者为hibernate，所以jpa的核心配置中兼容hibernate的配 -->
            <property name="hibernate.show_sql" value="true" />
            <property name="hibernate.format_sql" value="true" />
            <property name="hibernate.hbm2ddl.auto" value="update" />
        </properties>
    </persistence-unit>
</persistence>

 

创建实体类，并添加注解

 

import javax.persistence.*;

@Entity//作用：指定当前类是实体类
@Table(name = "cst_customer")//指定实体类和表之间的对应关系
public class Customer {

    @Id//声明当前私有属性为主键

    //配置主键的生成策略
    //GenerationType.IDENTITY  mysql使用
    //GenerationType.SEQUENCE  orcale使用
    @GeneratedValue(strategy= GenerationType.SEQUENCE)

    @Column(name="cust_id")
    private Long custId;
    @Column(name = "cust_name")
    private String custName;
    @Column(name = "cust_Source")
    private String custSource;
    @Column(name = "cust_industry")

    private String custIndustry;
    @Column(name = "cust_level")

    private String custLevel;
    @Column(name = "cust_address")

    private String custAddress;
    @Column(name = "cust_phone")
    private String custPhone;

    public Long getCustId() {
        return custId;
    }

    public void setCustId(Long custId) {
        this.custId = custId;
    }

    public String getCustName() {
        return custName;
    }

    public void setCustName(String custName) {
        this.custName = custName;
    }

    public String getCustSource() {
        return custSource;
    }

    public void setCustSource(String custSource) {
        this.custSource = custSource;
    }

    public String getCustIndustry() {
        return custIndustry;
    }

    public void setCustIndustry(String custIndustry) {
        this.custIndustry = custIndustry;
    }

    public String getCustLevel() {
        return custLevel;
    }

    public void setCustLevel(String custLevel) {
        this.custLevel = custLevel;
    }

    public String getCustAddress() {
        return custAddress;
    }

    public void setCustAddress(String custAddress) {
        this.custAddress = custAddress;
    }

    public String getCustPhone() {
        return custPhone;
    }

    public void setCustPhone(String custPhone) {
        this.custPhone = custPhone;
    }
}

 之后就可以开始测试了

@Test
public void run1(){
    //创建实体管理类工厂
    EntityManagerFactory myJpa = Persistence.createEntityManagerFactory("myJpa");
    //创建实体管理类
    EntityManager entityManager = myJpa.createEntityManager();
    //获取事务对象
    EntityTransaction transaction = entityManager.getTransaction();
    //开启事务
    transaction.begin();

    //模拟获取数据
    Customer customer = new Customer();
    customer.setCustName("**");
    customer.setCustLevel("**");
    customer.setCustAddress("***");

    //执行保存
    entityManager.persist(customer);
    //提交事务
    transaction.commit();
    //关闭资源
    entityManager.close();
    myJpa.close();
}

 

附加  Jpql语句

查询所有

From user

查询所有并倒序排列

From user order by userId desc

统计查询

Select count(id) from user

分页查询

String jpql = “From user”;

Query query = entityManager.createQuery(jpql);

query.setFirstResult(0);//开始的索引

query.setMaxResults(5);//每页显示的条数

 

模糊查询

String jpql = “From user where username like ?”;

Query query = entityManager.createQuery(jpql);

query.setParameter(1,"%虾%");