springboot 整合springDataJPA

〇、搭建springboot环境

一、添加依赖

• mysql

    <!-- mysql驱动 -->
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
    </dependency>

• springdatajpa

    <!-- springdata jpa依赖 -->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-data-jpa</artifactId>
    </dependency>

配置文件（src/main/resources/application.properties）

########################################################
###datasource
########################################################
spring.datasource.url = jdbc:mysql://localhost:3306/springboot
spring.datasource.username = root
spring.datasource.password = root
spring.datasource.driverClassName = com.mysql.jdbc.Driver
spring.datasource.max-active=20
spring.datasource.max-idle=8
spring.datasource.min-idle=8
spring.datasource.initial-size=10
########################################################
### Java Persistence Api
########################################################
# Specify the DBMS
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
#[org.hibernate.cfg.ImprovedNamingStrategy              #org.hibernate.cfg.DefaultNamingStrategy]
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

持久层

import org.springframework.data.repository.CrudRepository;
import com.xujie.pojo.Target;

public interface TargetRepository extends CrudRepository<Target,Integer>{
     
}

Entity

使用jpa的时候，一般先开发entity.因为如果配置文件配置了spring.jpa.hibernate.ddl-auto = update的话，jpa可以直接根据entity创建表；

示例：

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

@Entity(name="target")  
public class Target {
    @Id 
    @GeneratedValue  
    private int tid;
    @Column(name="tname",length=20)  
    private String tname;
    
    public int getTid() {
        return tid;
    }
    public void setTid(int tid) {
        this.tid = tid;
    }
    public String getTname() {
        return tname;
    }
    public void setTname(String tname) {
        this.tname = tname;
    }
    @Override
    public String toString() {
        return "Target [tid=" + tid + ", tname=" + tname + "]";
    }
}

service

import javax.annotation.Resource;
import org.springframework.stereotype.Service;
import com.xujie.pojo.Target;
import com.xujie.repository.TargetRepository;
import com.xujie.service.TargetService;

@Service
public class TargetServiceimpl implements TargetService {

    // @Resource是根据名称注入 @Autowired是根据类型注入
    @Resource
    private TargetRepository targetRepository;
    
    //添加
    @Override
    public void save(Target target) {
        this.targetRepository.save(target);
    }

    //删除
    @Override
    public void delete(Integer id) {
        this.targetRepository.delete(id);
    }

    //查询
    @Override
    public List<Target> findAll(){
        return (List<Target>) this.targetRepository.findAll();
    }
}

controller

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import com.xujie.pojo.Target;
import com.xujie.service.TargetService;

@RestController
public class TargetController {
    
    @Autowired
    private TargetService targetService;
    
    //添加
    @GetMapping("/save")
    public void save() {
        Target target = new Target();
        target.setTname("减肥");
        this.targetService.save(target);
    }

    //删除
    @GetMapping("/delete/{id}")
    public void delete(@PathVariable Integer id) {
        this.targetService.delete(id);
    }

    //查询所有
    @GetMapping("/findAll")
    public List<Target> findAll() {
        return this.targetService.findAll();

    }
}