上一篇我们讲了spring boot 整合JdbcTemplate来进行数据的持久化,
这篇我们来说下怎么通过spring boot 整合JPA来实现数据的持久化。
一、代码实现
- 修改pom,引入依赖
<!-- 引入jpa 依赖 -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency> - 修改application.properties,配置相关信息
#修改tomcat默认端口号
server.port=8090
#修改context path
server.context-path=/test #配置数据源信息
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3306/test
spring.datasource.username=root
spring.datasource.password=root
#配置jpa
spring.jpa.hibernate.ddl-auto=update
spring.jpa.show-sql=true
spring.jackson.serialization.indent_output=true - 创建实体类
package com.study.entity; import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table; @Entity
@Table(name="t_user")
public class User { @Id @GeneratedValue(strategy=GenerationType.AUTO)
private Integer id;
private String userName;
private String password; public Integer getId() {
return id;
} public void setId(Integer id) {
this.id = id;
} public String getUserName() {
return userName;
} public void setUserName(String userName) {
this.userName = userName;
} public String getPassword() {
return password;
} public void setPassword(String password) {
this.password = password;
} } - 创建repository接口并继承CrudRepository
package com.study.repository; import org.springframework.data.jpa.repository.Query;
import org.springframework.data.repository.CrudRepository;
import org.springframework.data.repository.query.Param; import com.study.entity.User; /**
* 注意:
* 1.这里这里是interface,不是class
*
* 2.CrudRepository里面的泛型,第一个是实体类,第二个是主键的类型
*
* 3.由于crudRepository 里面已经有一些接口了,如deleteAll,findOne等, 我们直接调用即可
*
* 4.当然,我们也可以根据自己的情况来实现自己的接口,如下面的getUser()方法,jpql语句和hql语句差不多
*
* */
public interface UserRepository extends CrudRepository<User, Integer> { /**
* 我们这里只需要写接口,不需要写实现,spring boot会帮忙自动实现
*
* */ @Query("from User where id =:id ")
public User getUser(@Param("id") Integer id);
} - 创建service
- 接口
package com.study.service; import com.study.entity.User; public interface UserService {
public User getUser(Integer id);
} - 实现
package com.study.service.impl; import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service; import com.study.entity.User;
import com.study.repository.UserRepository;
import com.study.service.UserService; @Service
public class UserServiceImpl implements UserService { @Autowired
UserRepository repository; @Override
public User getUser(Integer id) {
//有两种方式:
//1.调用crudRepository的接口
// return repository.findOne(id);
//2.调用我们自己写的接口
return repository.getUser(id);
} }
- 接口
- 创建controller
package com.study.controller; import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController; import com.study.entity.User;
import com.study.service.UserService; @RestController
public class UserController {
@Autowired
UserService service; @RequestMapping("/getUser/{id}")
public User getUser(@PathVariable("id") Integer id){ return service.getUser(id);
}
} - 测试,页面以json格式显示数据库值
二、知识点引申
关于Repository知识点,可以去看下下面这篇文章
https://segmentfault.com/a/1190000012346333