Spring data JPA 快速入门
向客户中插入一条数据
如果使用Jpa框架可以不用先建表 可以使用框架生成表
2 实现步骤
a 创建工程 使用maven管理工程
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.hibernate.version>5.0.7.Final</project.hibernate.version>
<maven.compiler.source>1.8</maven.compiler.source>
<maven.compiler.target>1.8</maven.compiler.target>
</properties>
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
</dependency>
<!--hibernate 对jpa的支持-->
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-entitymanager</artifactId>
<version>${project.hibernate.version}</version>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-c3p0</artifactId>
<version>${project.hibernate.version}</version>
</dependency>
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>1.2.17</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.6</version>
</dependency>
</dependencies>
b 创键一个配置文件
配置文件的路径必须是：META-INF/persistence.xml
配置连接数据库的相关配置
<?xml version="1.0" encoding="UTF-8"?>
<persistence xmlns="http://java.sun.com/xml/ns/persistence" version="2.0">
<!--配置持久化单元 在配置文件中至少有一个
name 持久化单元的名称
transaction-type 事物类型
RESOURCE_LOCAL 单数据库的事物
JTA 分布式事物 跨数据的事物 多个数据库的事物
-->
<persistence-unit name="myjpa" transaction-type="RESOURCE_LOCAL">
<properties>
<property name="javax.persistence.jdbc.user" value="root"/>
<property name="javax.persistence.jdbc.password" value="root"/>
<property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver"/>
<property name="javax.persistence.jdbc.url" value="jdbc:mysql://localhost:3306/sprign_data-9501"/>
<!--配置hibernate的属性-->
<property name="hibernate.show_sql" value="true"></property>
<!--sql语句是否格式化-->
<property name="hibernate.format_sql" value="true"/>
<!--是否自动创建数据库表
value 可选值 create update none
create 程序自动创建数据库表 如果表存在 先删除后创建
update 程序自动创建数据库表 如果表存在 不创建
none 不会创建
-->
<property name="hibernate.hbm2ddl.auto" value="create"/>
</properties>
</persistence-unit>
</persistence>
c： 创键一个Entry类 对应数据库中每个表创键一个实体类
package cn.lijun.jpa.entity;
import javax.persistence.*;
/**
* @author lijun
* @date 2019/8/14 10:38
*/
// 该类是jpa的实体类
@Entity
// 配置实体类和数据库表中映射关系 name 对应的表名
@Table(name="cust_customer")
public class Customer {
// 配置主键的生成策略 GenerationType.IDENTITY 自增长
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Id
//配置属性和字段名之间关系
@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 getCustNmae() {
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;
}
@Override
public String toString() {
return "Customer{" +
"custId=" + custId +
", custName='" + custName + '\'' +
", custSource='" + custSource + '\'' +
", custIndustry='" + custIndustry + '\'' +
", custLevel='" + custLevel + '\'' +
", custAddress='" + custAddress + '\'' +
", custPhone='" + custPhone + '\'' +
'}';
}
}
d: 编写测试程序 实现数据的添加
1 创键一个EntityManagerFactory 对象 使用完关闭
2 使用工厂对象EntityManagerFactory 就是一个连接
3 开启事物
4 创键 Customer 对象
5 使用Entitymanager 对象 的persist 方法向数据库添加数据
6 事物提交
7 关闭连接
package cn.lijun.jpa;
import cn.lijun.jpa.entity.Customer;
import org.junit.Test;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.EntityTransaction;
import javax.persistence.Persistence;
/**
* @author lijun
* @date 2019/8/14 10:52
*/
public class JpaTest {
@Test
public void firstTest(){
// 1 创键一个EntityManagerFactory 对象 使用完关闭
EntityManagerFactory factory = Persistence.createEntityManagerFactory("myjpa");
// 2 使用工厂对象EntityManagerFactory 就是一个连接
EntityManager entityManager = factory.createEntityManager();
// 3 开启事物
EntityTransaction transaction = entityManager.getTransaction();
transaction.begin();
// 4 创键 Customer 对象
Customer customer = new Customer();
customer.setCustName("ruirui");
customer.setCustLevel("vip");
customer.setCustSource("网络");
customer.setCustPhone("123456");
customer.setCustAddress("懒人中心");
// 5 使用Entitymanager 对象 的persist 方法向数据库添加数据
entityManager.persist(customer);
// 6 事物提交
transaction.commit();
// 7 关闭连接
entityManager.close();
factory.close();
}
}
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