springdata jpa单表操作crud

1. 项目搭建

使用boot整合，导入springdata jap, mysql 驱动，lombok，web。

1.1 配置

# boot add jpa, oh~ crud in single table

server:
  port: 8888
spring:
  # datasource
  datasource:
    username: root
    password: 123456
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://localhost:3306/mydatabase?useUnicode=true&characterEncoding=UTF-8&serverTimezone=Asia/Shanghai

  # jpa config
  jpa:
    hibernate:
      #配置创建表的相关操作
      ddl-auto: update
    #显示sql
    show-sql: true

1.2 实体类

package top.bitqian.springdatajpa.entity;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

import javax.persistence.*;
import java.math.BigDecimal;
import java.util.Date;

/**
 * @author echo lovely
 * @date 2021/1/10 16:06
 */

@Data
@NoArgsConstructor
@AllArgsConstructor
@Table(name = "programmer_info")
@Entity
public class ProgrammerInfo {
    
    
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Integer programmerId;

    @Column(name = "name", unique = true, nullable = false, length = 50)
    private String name;

    /**
     * 0 male
     * 1 female
     */
    private Integer gender;

    private Date personBirth;

    @Transient // 生成表的时候忽略money字段
    private BigDecimal money;
}

1.3 继承JpaRepository接口

package top.bitqian.springdatajpa.repository;

import org.springframework.data.jpa.repository.JpaRepository;
import top.bitqian.springdatajpa.entity.ProgrammerInfo;

/**
 * @author echo lovely
 * @date 2021/1/10 16:13
 */

public interface ProgrammerRepository extends JpaRepository<ProgrammerInfo, Integer> {
    
    

	// TODO: todo sth...
	
}

2. 批量新增

业务类

package top.bitqian.springdatajpa.service.impl;

import org.springframework.stereotype.Service;
import top.bitqian.springdatajpa.entity.ProgrammerInfo;
import top.bitqian.springdatajpa.repository.ProgrammerRepository;
import top.bitqian.springdatajpa.service.ProgrammerInfoService;

import javax.annotation.Resource;
import java.util.List;

/**
 * @author echo lovely
 * @date 2021/1/10 16:15
 */

@Service
public class ProgrammerInfoServiceImpl implements ProgrammerInfoService {
    
    

    @Resource
    private ProgrammerRepository programmerRepository;

    @Override
    public void saveBatch(List<ProgrammerInfo> programmerInfos) {
    
    

        programmerRepository.
                saveAll(programmerInfos).
                forEach(r -> System.out.println("批量新增完成 =>" + r));

    }
}

测试

package top.bitqian.springdatajpa;

import org.junit.jupiter.api.Test;
import org.springframework.boot.test.context.SpringBootTest;
import top.bitqian.springdatajpa.entity.ProgrammerInfo;
import top.bitqian.springdatajpa.service.ProgrammerInfoService;

import javax.annotation.Resource;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;

@SpringBootTest
class SpringdataJpaApplicationTests {
    
    

    @Resource
    private ProgrammerInfoService programmerInfoService;

    @Test
    void contextLoads() {
    
    

        List<ProgrammerInfo> list = new ArrayList<>();

        Date date = new Date();

        list.add(new ProgrammerInfo(null, "小千", 0, date, null));
        list.add(new ProgrammerInfo(null, "小小", 1, date, null));
        list.add(new ProgrammerInfo(null, "二哈", 0, date, null));

        programmerInfoService.saveBatch(list);

    }

}

3. 查询

1. 根据条件精确查询, Example作为参数。

       @Override
       public List<ProgrammerInfo> getProgrammerByInfo(ProgrammerInfo programmerInfo) {
         
         
   
           // 根据条件查询集合
           Example<ProgrammerInfo> example = Example.of(programmerInfo);
   
           return programmerRepository.findAll(example);
       }
   

       @Test
       void testGetProgrammerByInfo() {
         
         
   		// 根据姓名查询。
           ProgrammerInfo info = new ProgrammerInfo(null, "小小", null, null, null);
   
   
           programmerInfoService.getProgrammerByInfo(info).forEach(System.out::println);
       }
   

   

2. 自定义hql语句查询

    // 1. query by hql
    @Query(value = "from ProgrammerInfo pi where pi.name like ?1")
    List<ProgrammerInfo> findProgrammerByName(String name);

    @Test
    void testPrByName() {
    
    

        // 查询名称包含 '小'
        pr.findProgrammerByName("%小%").forEach(System.out::println);

    }

3. 自定义sql语句查询

    // 2. query by sql
    @Query(value = "select * from programmer_info where name like :#{#pi.name} and gender = :#{#pi.gender}", nativeQuery = true)
    List<ProgrammerInfo> findPrByPrInfo(@Param("pi") ProgrammerInfo programmerInfo);

    @Test
    void testPrByPr() {
    
    

        ProgrammerInfo info = new ProgrammerInfo(null, "%小%", 0, null, null);

        pr.findPrByPrInfo(info).forEach(System.out::println);
    }

4. 修改 by hql

sql也行，hql优先。

    // upd
    @Transactional
    @Modifying
    @Query(value = "update ProgrammerInfo p set p.name = :#{#pi.name}, p.personBirth = :#{#pi.personBirth} where p.programmerId = :#{#pi.programmerId}")
    void updPrById(@Param("pi") ProgrammerInfo programmerInfo);

    @Test
    void testPrUpd() {
    
    

        ProgrammerInfo info = new ProgrammerInfo(1, "小小可爱", 0, new Date(), null);


        pr.updPrById(info);

    }

5. 删除 by hql

    // del
    @Transactional
    @Modifying
    @Query(value = "delete from ProgrammerInfo where programmerId = :#{#pi.programmerId}")
    void delPrById(@Param("pi") ProgrammerInfo programmerInfo);

    @Test
    void testPrDel() {
    
    
        ProgrammerInfo info = new ProgrammerInfo(1, null, 0, null, null);

        pr.delPrById(info);

    }

---

坑：
1. 修改操作得加上事务控制。
2. @Query 进行操作时，占位符使用注意套娃。不要套错。

单表操作可以的，但是mybatisPlus 更easy.jpg.