SpringDataJPA笔记(3)-基于SpringBoot基础用法

一时失言乱红尘 2022-02-05 04:53 228阅读 0赞

基于SpringBoot的基础用法

#### STEP1. 引入POM依赖 ####

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

这里有一个使用Specification查询时很好用的工具包，感谢做工具包的同学

<dependency>
        <groupId>com.github.wenhao</groupId>
        <artifactId>jpa-spec</artifactId>
    	<version>3.2.4</version>
    </dependency>

#### STEP2. 配置文件application.yml ####

spring:
      jpa:
        hibernate:
          ddl-auto: update
        show-sql: true #打印sql语句，方便调试
        database-platform: org.hibernate.dialect.MySQL5InnoDBDialect #设置数据库引擎为InnoDB
        properties:
          hibernate:
            format-sql: true #是否格式化输出字符串,增强SQL的可读性

#### STEP3. 实体类 ####

这里写了一个抽象实体类和两个具体的实体类

抽象类

AnimalEntity.java

@Data
    @EqualsAndHashCode(callSuper = false)
    @MappedSuperclass
    public abstract class AnimalEntity<ID> implements Serializable {
    
        @Id
        @GeneratedValue(strategy = GenerationType.IDENTITY)
        private ID id;
    
    
        @Temporal(TemporalType.TIMESTAMP)
        @CreationTimestamp
        @Column(name = "gmt_create", nullable = false, updatable = false)
        @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss", timezone = "GMT+8")
        protected Date gmtCreate;
    
        @Temporal(TemporalType.TIMESTAMP)
        @UpdateTimestamp
        @Column(name = "gmt_update", nullable = true, insertable = false)
        @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss", timezone = "GMT+8")
        @JSONField
        protected Date gmtUpdate;
    
        private String name;
    
        private Integer age;
    
        private String sex;
    
        private Integer height;
    
        private Integer weight;
    
        private Long pid;
    
    }

实际会对应数据库表的实体类

CatEntity.java

@Data
    @Entity
    @Table(name = "cat_tb")
    @EqualsAndHashCode(callSuper = false)
    public class CatEntity extends AnimalEntity<Long> {
    
    
        private static final long serialVersionUID = 7456065103323391049L;
    
        private String miao;
    }

DogEntity.java

@Data
    @Entity
    @Table(name = "dog_tb")
    @EqualsAndHashCode(callSuper = false)
    public class DogEntity extends AnimalEntity<Long> {
    
    
        private static final long serialVersionUID = 7456065103323391049L;
    
        private String wang;
    }

#### STEP4. repository类 ####

同样写了一个base类和两个对应的操作类

@NoRepositoryBean
    public interface BaseRepository<T, ID extends Serializable> extends JpaRepository<T, ID>, JpaSpecificationExecutor<T>, Serializable {
    }

public interface CatRepository extends BaseRepository<CatEntity, Long> {
    }

public interface DogRepository extends BaseRepository<DogEntity, Long> {
    }

然后写一个测试的controller来测试

这是几个基础的单表查询

ChapterThreeController

@ApiOperation(value = "获取所有的猫", httpMethod = "GET")
        @GetMapping("/find/cat")
        public List<CatEntity> findCat() {
            return catRepository.findAll();
        }
    
        @ApiOperation(value = "findById", httpMethod = "GET")
        @GetMapping("/find/cat/{id}")
        public CatEntity findOneCatById(@PathVariable Long id) {
            return catRepository.findById(id).orElse(null);
        }
    
        @ApiOperation(value = "分页查询", httpMethod = "GET")
        @GetMapping("/find/cat/page")
        public Page<CatEntity> findCatByPage(@RequestParam int pageSize, @RequestParam int pageNum) {
            Pageable pageable = PageRequest.of(pageNum, pageSize);
            return catRepository.findAll(pageable);
        }
    
        @ApiOperation(value = "分页排序查询", httpMethod = "GET")
        @GetMapping("/find/cat/order")
        public Page<CatEntity> findCatByPageOrder(@RequestParam int pageSize, @RequestParam int pageNum) {
            Pageable pageable = PageRequest.of(pageNum, pageSize, new Sort(Sort.Direction.DESC, "id"));
            return catRepository.findAll(pageable);
        }
    
        @ApiOperation(value = "分页条件查询", httpMethod = "GET")
        @GetMapping("/find/cat/search")
        public Page<CatEntity> findCatByPageOrder(@RequestParam int pageSize, @RequestParam int pageNum, @RequestParam String miao) {
            Pageable pageable = PageRequest.of(pageNum, pageSize, new Sort(Sort.Direction.DESC, "id"));
            Specification<CatEntity> specification = Specifications.<CatEntity>and().eq(!StringUtils.isEmpty(miao), "miao", miao).build();
            return catRepository.findAll(specification, pageable);
        }

源码参考 [GITHUB][]  
欢迎关注微信交流  
![在这里插入图片描述][70]

[GITHUB]: https://github.com/yingziisme/spring-boot-jpa-demo
[70]: /images/20220205/8c1acc88b1d345708f40bf5525e4f479.png