spring data jpa 使用之 spring boot 2.x

准备

本人写的spring data是通过maven子父工程管理

parent项目的 :

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>spring-boot-data</artifactId>
        <groupId>com.ronnie</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>spring-data-jpa</artifactId>

    <dependencies>
        <!-- https://mvnrepository.com/artifact/com.alibaba/fastjson -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.2.49</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jdbc</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>provided</scope>
        </dependency>
    </dependencies>

</project>
           

propertise

server:
  port: 8080
spring:
  datasource:
    url: jdbc:mysql://ip/jpa?characterEncoding=utf-8
    username: root
    password: pass
  jpa:
    hibernate:
      ddl-auto: update
    show-sql: true
    #不加这句则默认为myisam引擎
    database-platform: org.hibernate.dialect.MySQL5InnoDBDialect
           

注意注释 !!!

默认为myisam引擎 boot2.x 的特性

一、 实体类

1.Member

package com.ronnie.data.entity;

import com.fasterxml.jackson.annotation.JsonIgnore;
import lombok.Data;

import javax.persistence.*;
import java.io.Serializable;

/**
* @Description:
* @Author: rongyu
* @CreateDate: 2018/8/31$ 10:06$
* @Remark:
*/
@Data
@Table
@Entity
public class Member implements Serializable {
   @Id
   @GeneratedValue(strategy = GenerationType.IDENTITY)
   private Long id;

   private String username;

   @JsonIgnore
   private String password;

}
           

MemberOrder

如果用order请修改映射表名 order为数据库关键字 生成DDL 语法错误

package com.ronnie.data.entity;

import lombok.Data;
import org.hibernate.annotations.CreationTimestamp;

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

/**
 * @Description:
 * @Author: rongyu
 * @CreateDate: 2018/9/1$ 15:33$
 * @Remark:
 */
@Data
@Table
@Entity
public class MemberOrder {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    private String goodsName;

    private Integer number;

    @JoinColumn(name = "member_id")
    @ManyToOne
    private Member member;

    @CreationTimestamp
    private Date creationTime;

}
           

Dao

继承JpaRepository 就可以直接使用接口里面的方法

package com.ronnie.data.repository;

import com.ronnie.data.entity.Member;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.repository.PagingAndSortingRepository;

/**
 * @Description:
 * @Author: rongyu
 * @CreateDate: 2018/8/31$ 10:12$
 * @Remark:
 */
public interface MemberDao extends JpaRepository<Member,Long>{
}
           

查询

package com.ronnie.data;

import com.ronnie.data.entity.Member;
import com.ronnie.data.entity.MemberOrder;
import com.ronnie.data.repository.MemberDao;
import com.ronnie.data.repository.MemberOrderDao;
import lombok.extern.slf4j.Slf4j;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.data.domain.Example;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.PageRequest;
import org.springframework.data.domain.Sort;
import org.springframework.test.context.junit4.SpringRunner;

import java.util.Optional;

@Slf4j
@RunWith(SpringRunner.class)
@SpringBootTest
public class ApplicationTests {

    @Autowired
    MemberDao memberDao;
    @Autowired
    MemberOrderDao orderDao;

    @Test
    public void addTestData() throws InterruptedException {
        // Member member = memberDao.getOne(1L); bad way
        Optional<Member> optionalMember = memberDao.findById(1L);
        Member member = optionalMember.get();
        for (int i = 0; i < 12; i++) {
            MemberOrder order = new MemberOrder();
            order.setGoodsName("coco");
            order.setMember(member);
            order.setNumber(10);
            Thread.sleep(1000);
            orderDao.save(order);
        }
    }

    @Test
    public void queryDemo() {
        // add condition
        MemberOrder order = new MemberOrder();
        Member member = new Member();
        member.setUsername("root");
        order.setMember(member);
        Example<MemberOrder> example = Example.of(order);
        // add order by
        Sort.Order order1 = new Sort.Order(Sort.Direction.DESC, "id");
        Sort.Order order2 = new Sort.Order(Sort.Direction.ASC, "number");
        Sort sort = Sort.by(order1, order2);
        // add pageable
        PageRequest pageRequest = PageRequest.of(0, 10, sort);
        // findAll with page
        Page<MemberOrder> result = orderDao.findAll(example, pageRequest);
        log.info("result={}", result);
    }

}
           

jpaJpaRepository 接口之中所有方法，接受的都是分页查询过程中的对象，直接调用即可

github

https://github.com/ronnierry/spring-boot-data/tree/master/spring-data-jpa

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