SpringBoot系列之JPA实现按年月日查询

通过例子的方式介绍Springboot集成Spring Data JPA的方法，进行实验，要先创建一个Initializer工程，如图：在这里插入图片描述
选择，需要的jdk版本，maven项目

选择需要的maven配置，这里需要选择spring data jpa，数据库驱动mysql driver

新建项目后，会自动加上如下配置，如果你的mysql服务器是5.7版本的，建议指定mysql-connector-java版本，Druid也需要自己加上，pom配置参考：

<properties><java.version>1.8</java.version><druid.version>1.1.2</druid.version></properties><dependencies><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-data-jpa</artifactId></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>8.0.21</version><scope>runtime</scope></dependency><!-- https://mvnrepository.com/artifact/com.alibaba/druid --><dependency><groupId>com.alibaba</groupId><artifactId>druid</artifactId><version>${druid.version}</version></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-test</artifactId><scope>test</scope><exclusions><exclusion><groupId>org.junit.vintage</groupId><artifactId>junit-vintage-engine</artifactId></exclusion></exclusions></dependency></dependencies>

新建数据库和数据表

CREATE DATABASE /*!32312 IF NOT EXISTS*/`springboot` /*!40100 DEFAULT CHARACTER SET utf8 */;USE `springboot`;/*Table structure for table `sys_user` */DROP TABLE IF EXISTS `sys_user`;CREATE TABLE `sys_user` (`userId` int(10) NOT NULL,`username` varchar(20) NOT NULL,`sex` char(10) DEFAULT NULL,`password` varchar(10) DEFAULT NULL,`create_time` datetime DEFAULT NULL COMMENT '创建时间',`modify_time` datetime DEFAULT NULL COMMENT '修改时间',PRIMARY KEY (`userId`),UNIQUE KEY `idx_username` (`username`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;/*Data for the table `sys_user` */insert  into `sys_user`(`userId`,`username`,`sex`,`password`, `create_time`, `modify_time`) values (1,'admin','man','11', now(), now());

注意，如果mysql数据库版本是5.x版本的，驱动就是com.mysql.jdbc.Driver

spring:datasource:url: jdbc:mysql://127.0.0.1:3306/springboot?characterEncoding=utf8&useSSL=trueusername: rootpassword: rootdriver-class-name: com.mysql.cj.jdbc.Driverinitialization-mode: alwaystype: com.alibaba.druid.pool.DruidDataSource# 连接池设置initial-size: 5min-idle: 5max-active: 20# 配置获取连接等待超时的时间max-wait: 60000# 配置间隔多久才进行一次检测，检测需要关闭的空闲连接，单位是毫秒time-between-eviction-runs-millis: 90000# 配置一个连接在池中最小生存的时间，单位是毫秒min-evictable-idle-time-millis: 300000# Oracle请使用select 1 from dualvalidation-query: SELECT 1test-while-idle: truetest-on-borrow: falsetest-on-return: false# 打开PSCache，并且指定每个连接上PSCache的大小pool-prepared-statements: truemax-pool-prepared-statement-per-connection-size: 20# 配置监控统计拦截的filters，去掉后监控界面sql无法统计，'wall'用于防火墙filters: stat,wall,slf4j# 通过connectProperties属性来打开mergeSql功能；慢SQL记录connection-properties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=5000# 合并多个DruidDataSource的监控数据use-global-data-source-stat: truejpa:hibernate:#     更新或者创建数据表结构ddl-auto: updatenaming:physical-strategy: org.hibernate.boot.model.naming.PhysicalNamingStrategyStandardImpl#    控制台显示SQLshow-sql: true

新建一个实体类

package com.example.springboot.jpa.entity;import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
import lombok.Data;import javax.persistence.*;
import java.util.Date;@Entity
@Table(name = "sys_user")
@JsonIgnoreProperties({"hibernateLazyInitializer","handler"})
@Data
public class User{@Id //主键@GeneratedValue(strategy = GenerationType.IDENTITY)//自增主键private Integer userId;@Column(name = "username",length = 20) //这是和数据表对应的一个列private String username;@Column(name = "sex")private String sex;@Column(name = "password")private String password;@Column(name = "create_time")private Date createTime;}

新增mapper接口，继承JpaRepository和JpaSpecificationExecutor ，继承JpaSpecificationExecutor 是为了支持Specification的API

package com.example.springboot.jpa.repository;import com.example.springboot.jpa.entity.User;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.jpa.repository.JpaSpecificationExecutor;public interface UserRepository extends JpaRepository<User,Integer>, JpaSpecificationExecutor {}

业务实现类，这里实现按年月日查询思路是借助Specification来实现，获取传入的时间戳，只获取对应的年月日，startTime再拼上00:00:00，endTime拼上23:59:59，再将createTime转为字符串类型来比较

package com.example.springboot.jpa.service.impl;import cn.hutool.core.collection.CollUtil;
import cn.hutool.core.date.DatePattern;
import cn.hutool.core.date.DateTime;
import cn.hutool.core.date.DateUtil;
import cn.hutool.core.util.ObjectUtil;
import cn.hutool.core.util.StrUtil;
import com.example.springboot.jpa.dto.UserSearchDto;
import com.example.springboot.jpa.entity.User;
import com.example.springboot.jpa.repository.UserRepository;
import com.example.springboot.jpa.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.domain.Sort;
import org.springframework.data.jpa.domain.Specification;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;import javax.persistence.criteria.*;
import java.time.LocalDateTime;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import java.util.Optional;@Service
public class UserServiceImpl implements UserService {@Autowiredprivate UserRepository userRepository;@Overridepublic List<User> listUser(UserSearchDto searchDto) {Specification<User> specification = new Specification<User>() {@Overridepublic Predicate toPredicate(Root<User> root, CriteriaQuery<?> criteriaQuery, CriteriaBuilder criteriaBuilder) {Predicate predicate = criteriaBuilder.conjunction();Path<Object> createTime = root.get("createTime");Path<Object> username = root.get("username");if (ObjectUtil.isNotNull(searchDto.getStartTime())) {LocalDateTime localDateTime = DateUtil.toLocalDateTime(searchDto.getStartTime());LocalDateTime createDateStart = LocalDateTime.of(localDateTime.getYear(), localDateTime.getMonthValue(), localDateTime.getDayOfMonth(), 00, 00, 00);Predicate pSTime = criteriaBuilder.greaterThanOrEqualTo(createTime.as(String.class), DateUtil.format(new DateTime(createDateStart), DatePattern.NORM_DATETIME_PATTERN));predicate.getExpressions().add(pSTime);}if (ObjectUtil.isNotNull(searchDto.getEndTime())) {LocalDateTime localDateTime = DateUtil.toLocalDateTime(searchDto.getEndTime());LocalDateTime createDateEnd = LocalDateTime.of(localDateTime.getYear(), localDateTime.getMonthValue(), localDateTime.getDayOfMonth(), 23, 59, 59);Predicate pETime = criteriaBuilder.lessThanOrEqualTo(createTime.as(String.class), DateUtil.format(new DateTime(createDateEnd), DatePattern.NORM_DATETIME_PATTERN));predicate.getExpressions().add(pETime);}if (StrUtil.isNotBlank(searchDto.getUserName())) {Predicate pUserName = criteriaBuilder.like(username.as(String.class), searchDto.getUserName());predicate.getExpressions().add(pUserName);}return predicate;}};return Optional.ofNullable(userRepository.findAll(specification)).orElse(Collections.EMPTY_LIST);}
}