Spring data JPA简单使用

不念不忘少年蓝@ 2022-05-16 03:53 272阅读 0赞

JPA是Spring data 提供的一款基于hibernate封装的持久化的工具  
让开发不写sql语句就可以快速的增删查改

1、项目中增加依赖，集成进来

<dependency>
                <groupId>com.querydsl</groupId>
                <artifactId>querydsl-apt</artifactId>
                <version>${querydsl.version}</version>
                <scope>provided</scope>
            </dependency>
            <dependency>
                <groupId>javax.inject</groupId>
                <artifactId>javax.inject</artifactId>
                <version>1</version>
            </dependency>
            <dependency>
                <groupId>com.querydsl</groupId>
                <artifactId>querydsl-jpa</artifactId>
                <version>${querydsl.version}</version>
            </dependency>
    
            <dependency>
                <groupId>com.h2database</groupId>
                <artifactId>h2</artifactId>
                <scope>runtime</scope>
            </dependency>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-data-jpa</artifactId>
            </dependency>
            <dependency>
                <groupId>org.hibernate</groupId>
                <artifactId>hibernate-core</artifactId>
                <version>5.2.12.Final</version>
            </dependency>
            <dependency>
                <groupId>org.hibernate</groupId>
                <artifactId>hibernate-entitymanager</artifactId>
                <version>5.2.12.Final</version>
            </dependency>
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
                <scope>runtime</scope>
            </dependency>
            <dependency>
                <groupId>com.vaadin.external.google</groupId>
                <artifactId>android-json</artifactId>
                <version>RELEASE</version>
            </dependency>

以上是我们项目中的依赖的包，比较多，大家可以根据自己项目情况灵活的配置。  
2、实体类怎么写

import io.swagger.annotations.ApiModelProperty;
    import lombok.Data;
    
    import javax.persistence.Entity;
    import javax.persistence.Id;
    import javax.persistence.Table;
    import javax.persistence.Transient;
    import java.math.BigDecimal;
    import java.util.Date;
    import java.util.List;
    
    @Data
    @Entity
    @Table(name = "RM_RmaReturnDetail")
    public class AaDetail {
        @ApiModelProperty(notes = "主键ID")
        @Id
        private Long id;
    
        @ApiModelProperty(notes = "返还ID")
        @Transient
        private Long aaId;
    
        @ApiModelProperty(notes = "备件粒度")
        @Transient
        private String materialGranularity;
    
        @ApiModelProperty(notes = "备件粒度名称")
        @Transient
        private String materialGranularityName;
    
    
        @ApiModelProperty(notes = "归还单号")
        private String code;

其中的依赖的

import javax.persistence.Entity;
    import javax.persistence.Id;
    import javax.persistence.Table;
    import javax.persistence.Transient;

会发现都是来自于hibernate-jpa-2.1-api-1.0.0.Final.jar包  
3、Repository接口定义使用

p
    import com.querydsl.core.types.dsl.BooleanExpression;
    import com.querydsl.core.types.dsl.Expressions;
    import org.springframework.data.domain.Page;
    import org.springframework.data.domain.PageRequest;
    import org.springframework.data.querydsl.QueryDslPredicateExecutor;
    import org.springframework.data.repository.PagingAndSortingRepository;
    import org.springframework.util.StringUtils;
    
    import java.util.List;
    
    public interface RmaReturnDetailRepository extends PagingAndSortingRepository<RmaReturnDetail,Long>,QueryDslPredicateExecutor<RmaReturnDetail> {
        List<RmaReturnDetail> findByOrderCodeAndMaterialCodeAndIdIn(String orderCode, String materialCode,List<Long> idList);
        List<RmaReturnDetail> findByOrderCodeInAndMaterialCodeIn(List<String> orderCode, List<String> materialCode);
        //查询维修订单明细对应的签收明细
        List<RmaReturnDetail> findByRmaOrderDetailId(Long rmaOrderDetailId);
        List<RmaReturnDetail> findByRmaOrderDetailIdIn(List<Long> rmaOrderDetailIdList);
        List<RmaReturnDetail> findByIdIn(List<Long> idList);
        default Page<RmaReturnDetail> queryPage(RmaReturnDetailCriteria query, PageRequest pageRequest) {
            BooleanExpression last = Expressions.asBoolean(true).isTrue();
            if(!org.springframework.util.StringUtils.isEmpty(query.getSupplierCode())){
                last = last.and(QRmaReturnDetail.rmaReturnDetail.supplierCode.eq(query.getSupplierCode()));
            }
            if(!org.springframework.util.StringUtils.isEmpty(query.getLegalPersonCode())){
                last = last.and(QRmaReturnDetail.rmaReturnDetail.legalPersonCode.eq(query.getLegalPersonCode()));
            }
            if(!StringUtils.isEmpty(query.getLegalPersonCodes())){
                last = last.and(QRmaReturnDetail.rmaReturnDetail.legalPersonCode.in(query.getLegalPersonCodes()));

注意上面定义的是一个接口，要集成父类的接口PagingAndSortingRepository，并且是指定针对我们定义的上面的实体类进行操作的。 简单列一下常用的写法，项目用最多的是findBy…查询语句。  
![这里写图片描述][70]

4、在service注入使用

@Service
    @Slf4j
    public class RmaReturnDetailServiceImpl implements RmaReturnDetailService {
        @Autowired
        private RmaReturnDetailRepository rmaReturnDetailRepository;

[70]: /images/20220516/b7507a71076b4188aab8e8090b9b29a9.png