Springboot 整合 hibernate 和 jpa

柔光的暖阳◎ 2023-10-18 18:28 62阅读 0赞

hibernate 和 jpa 的关系这里就不介绍了，你可以这么理解：hibernate用jpa的方式来实现

#### **1.引入依赖 （jpa里面已经有了hiebrnate的依赖包）** ####

<dependency>
         <groupId>org.springframework.boot</groupId>
         <artifactId>spring-boot-starter-data-jpa</artifactId>
    </dependency>
    <dependency>
         <groupId>mysql</groupId>
         <artifactId>mysql-connector-java</artifactId>
    </dependency>

#### **2.修改 application.properties** ####

datasource的参数跟你整合mybatis一样，不过整合hibernate还得指定jpa的配置

#datasource
    spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
    spring.datasource.url=jdbc:mysql://localhost:3306/springboot?useUnicode=true&characterEncoding=utf-8&useSSL=false&serverTimezone=UTC
    spring.datasource.username=root
    spring.datasource.password=123
    
    #jpa配置
    spring.jpa.database = MYSQL
    # Show or not log for each sql query
    spring.jpa.show-sql = true
    # Hibernate ddl auto (create, create-drop, update)
    spring.jpa.hibernate.ddl-auto = update
    # Naming strategy
    spring.jpa.hibernate.naming-strategy = org.hibernate.cfg.ImprovedNamingStrategy
    # stripped before adding them to the entity manager)
    spring.jpa.properties.hibernate.dialect = org.hibernate.dialect.MySQL5Dialect

#### **3.创建实体类（这里用注解式开发，没有了.hbm.xml文件）** ####

通过注解将表名和类名，字段名和属性名关联起来，还有指定主键生成策略

package com.liqiye.springbootdemo.entity;
    
    import java.io.Serializable;
     
    import javax.persistence.Column;
    import javax.persistence.GeneratedValue;
    import javax.persistence.GenerationType;
    import javax.persistence.Id;
    import javax.persistence.MappedSuperclass;
    import javax.persistence.Entity;
    import javax.persistence.Table;
    
    /**
     * @author liqiye
     * @description hibernate的实体类
     * @date 2019/5/11
     */
    @Entity    // @Entity标识一个实体类，任何Hibernate映射对象都要有这个注解
    @Table(name = "Person")
    public class Person implements Serializable{
        
        @Id
        // @GeneratedValue(strategy = GenerationType.AUTO)  // 这个和默认一样是以Oracle的方式来实现自增主键，会自动生成hibernate_sequence表
        @GeneratedValue(strategy = GenerationType.IDENTITY)
        protected Long id;
        @Column(name = "name")
        protected String name;
     
        public Long getId() {
            return id;
        }
     
        public void setId(Long id) {
            this.id = id;
        }
     
        public String getName() {
            return name;
        }
     
        public void setName(String name) {
            this.name = name;
        }
    
        @Override
        public String toString() {
            return "Person{" +
                    "id=" + id +
                    ", name='" + name + '\'' +
                    '}';
        }
    }

#### **4.定义数据库操作接口** ####

类似mybatis的mapper接口一样，包含操作数据库的方法，注入到service层使用，这里用的jpa，继承 JpaRepository 类

JpaRepository 的子类已经实现了简单的增删改查的方法，我们也可以自定义HQL的方法

package com.liqiye.springbootdemo.mapper;
    
    import com.liqiye.springbootdemo.entity.Person;
    import org.springframework.data.jpa.repository.JpaRepository;
    import org.springframework.data.jpa.repository.Query;
    import org.springframework.data.repository.query.Param;
    
    // hibernate的接口，springboot整合hibernate用的是jpa，接口要集成JpaRepository
    // 里面已经集成了几个方法，额外的查询需要我们手动添加方法HQL
    
    public interface PersonRepository extends JpaRepository<Person,Integer> {
        public Person findById(Long id);  // 这个在集成的类的子类里面有明确的sql实现，不用再写SQL或者HQL，也可以不写，直接在service里用子类的
    
        public Person save(Person user);  // 同上
    
        @Query(value = "SELECT p FROM Person p WHERE name=:name")   // 这是HQL  :xx 指传入参数，跟下面注解@Param对应
        // @Query(value = "SELECT * FROM Person WHERE name=?", nativeQuery = true)   // 这是SQL   nativeQuery为true代表使用SQL语言
        public Person findByName(@Param("name") String name);
    
    }

#### **5.service**  ####

package com.liqiye.springbootdemo.service;
    
    import com.liqiye.springbootdemo.entity.Person;
    import com.liqiye.springbootdemo.mapper.PersonRepository;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.stereotype.Service;
    
    /**
     * @author liqiye
     * @description
     * @date 2019/5/11
     */
    @Service
    public class PersonService {
    
        @Autowired
        private PersonRepository personRepository;
    
        public Person findById(Long id){
            return personRepository.findById(id);
        }
    
        public Person findByName(String name){
            return personRepository.findByName(name);
        }
    
        public void save(Person person){
            personRepository.save(person);
        }
    
    }

#### **5.controller** ####

package com.liqiye.springbootdemo.controller;
    
    import com.liqiye.springbootdemo.entity.Person;
    import com.liqiye.springbootdemo.service.PersonService;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.stereotype.Controller;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.ResponseBody;
    
    /**
     * @author liqiye
     * @description
     * @date 2019/5/11
     */
    @Controller
    public class PersonController {
    
        @Autowired
        private PersonService personService;
    
        @RequestMapping("/findById")
        @ResponseBody
        public String findById(String id){
            return personService.findById(Long.parseLong(id)).toString();
        }
    
        @RequestMapping("/findByName")
        @ResponseBody
        public String findByName(String name){
            return personService.findByName(name).toString();
        }
    
        @RequestMapping("/save")
        @ResponseBody
        public String save(){
            Person person = new Person();
            person.setName("张三");
            personService.save(person);
            return "插入成功";
        }
    
    }

#### **6.测试** ####

运行项目，发现数据库自动创建了person 表

发起接口请求 [http://localhost:8080/save][http_localhost_8080_save] 成功插入数据

发起接口请求 [http://localhost:8080/findById?id=1][http_localhost_8080_findById_id_1] 成功返回一条person数据

发起接口请求 [http://localhost:8080/findByName?name=张三][http_localhost_8080_findByName_name] 成功返回一条person数据

总结：整体下来，跟整合mybatis的用法大同小异，只不过其中的具体实现有点差别。

[http_localhost_8080_save]: http://localhost:8080/save
[http_localhost_8080_findById_id_1]: http://localhost:8080/findById?id=1
[http_localhost_8080_findByName_name]: http://localhost:8080/findByName?name=%E5%BC%A0%E4%B8%89