Spring Boot整合JPA

一、POM

<?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"><modelVersion>4.0.0</modelVersion><groupId>com.squirrel</groupId><artifactId>squirrel-web</artifactId><version>1.0-SNAPSHOT</version><!-- Spring boot 父引用--><parent><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-parent</artifactId><version>2.0.0.RELEASE</version></parent><!-- Spring boot 核心web--><dependencies><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>5.1.21</version></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-data-jpa</artifactId><version>2.1.0.BUILD-SNAPSHOT</version></dependency><dependency><groupId>com.google.guava</groupId><artifactId>guava</artifactId><version>18.0</version></dependency></dependencies></project>

二、配置文件

#监听端口号
server.port=8888
#用户会话session过期时间，以秒为单位
server.session-timeout=7200
#数据库配置
spring.datasource.url=jdbc:mysql://localhost:3306/test
spring.datasource.username=root
spring.datasource.password=123456
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
#输出日志级别
logging.level.org.springframework.web=DEBUG#JPA
#1表结构：update自动更新，none不采取措施
spring.jpa.hibernate.ddl-auto=update
#2显示sql
spring.jpa.show-sql=true
#3让控制器输出的json字符格式更美观
spring.jackson.serialization.indent-output=true

三、启动类

package com.squirrel;import com.squirrel.support.CustomRepositoryFactoryBean;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;@SpringBootApplication
@ComponentScan(basePackages={"com.squirrel"})
@EnableJpaRepositories(repositoryFactoryBeanClass = CustomRepositoryFactoryBean.class)
public class StartApplication {public static void main(String[] args) {SpringApplication.run(StartApplication.class, args);}
}

四、entity

package com.squirrel.entity;import javax.persistence.*;@Entity
public class User {private Long id;private String name;private Integer age;public User() {super();}public User(String name, Integer age) {this.name = name;this.age = age;}@Id@GeneratedValuepublic Long getId() {return id;}public void setId(Long id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}public Integer getAge() {return age;}public void setAge(Integer age) {this.age = age;}
}

五、分页模糊查询方法封装

package com.squirrel.specs;import static com.google.common.collect.Iterables.toArray;import com.squirrel.entity.User;
import org.springframework.data.jpa.domain.Specification;
import org.springframework.util.ReflectionUtils;
import org.springframework.util.StringUtils;import java.lang.reflect.Field;
import java.util.ArrayList;
import java.util.List;import javax.persistence.EntityManager;
import javax.persistence.criteria.CriteriaBuilder;
import javax.persistence.criteria.CriteriaQuery;
import javax.persistence.criteria.Predicate;
import javax.persistence.criteria.Root;
import javax.persistence.metamodel.Attribute;
import javax.persistence.metamodel.EntityType;
import javax.persistence.metamodel.SingularAttribute;public class CustomerSpecs {/*** 1.定义一个返回值为Specification的方法byAuto，这里使用的是泛型 T，所以这个Specification是可以用于任意的实体类的，* 它接受的参数是entityManager和当前的包含值作为查询条件的实体类对象*/public  static <T> Specification<T> byAuto(final EntityManager entityManager,final  T example){/*** 2.获得当前实体类对象类的类型*/final Class<T> type = (Class<T>) example.getClass();return new Specification<T>() {@Overridepublic Predicate toPredicate(Root<T> root, CriteriaQuery<?> query, CriteriaBuilder cb) {/*** 3.新建Predicate列表存储构造的查询条件*/List<Predicate> predicates = new ArrayList<>();/*** 4.获取实体类的EntityType，我们可以从EntityType获取实体类的属性*/EntityType<T> entity = entityManager.getMetamodel().entity(type);/*** 5.对实体类的所有属性做循环*/for (Attribute<T,?> attr : entity.getDeclaredAttributes()) {/*** 6.获得实体类对象某一个属性的值*/Object attrValue = getValue(example, attr);if(attrValue != null){/*** 7.当前属性值为字符类型的时候*/if(attr.getJavaType() == String.class) {/*** 8.若当前字符不为空的情况下*/if(!StringUtils.isEmpty(attrValue)){/*** 构造当前属性like（前后%）属性值查询条件，并添加到条件列表中*/predicates.add(cb.like(root.get(attribute(entity, attr.getName(),String.class)),panttern((String) attrValue)));}}else{/*** 10.其余情况下，构造属性和属性值equal查询条件，并添加到条件列表中*/predicates.add(cb.equal(root.get(attribute(entity, attr.getName(),attrValue.getClass())),attrValue));}}}/*** 11.将条件列表转换成Predicate*/return predicates.isEmpty() ? cb.conjunction() : cb.and(toArray(predicates, Predicate.class));}/*** 12.通过反射获得实体类对象对应属性的属性值*/private <T> Object getValue(T example, Attribute<T, ?> attr){Field field = null;try {field = example.getClass().getDeclaredField(attr.getName());//设置对象的访问权限，保证对private的属性的访问field.setAccessible(true);return ReflectionUtils.getField(field,example);} catch (NoSuchFieldException e) {e.printStackTrace();return null;}}/*** 13.获得实体类的当前属性的SingularAttribute，SingularAttribute包含的是实体类的某个单独属性*/private <E,T> SingularAttribute<T, E> attribute(EntityType<T> entity, String fileName, Class<E> fieldClass) {return entity.getDeclaredSingularAttribute(fileName,fieldClass);}};}/*** 14.构造like的查询模式，即前后加%*/static  private String panttern(String str) {return "%" + str + "%";}
}

package com.squirrel.support;import org.springframework.data.domain.Page;
import org.springframework.data.domain.Pageable;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.jpa.repository.JpaSpecificationExecutor;
import org.springframework.data.repository.NoRepositoryBean;import java.io.Serializable;@NoRepositoryBean
public interface CustomRepository<T, ID extends Serializable> extends JpaRepository<T, ID> ,JpaSpecificationExecutor<T> {Page<T> findByAuto(T example, Pageable pageable);}

package com.squirrel.support;import org.springframework.data.domain.Page;
import org.springframework.data.domain.Pageable;
import org.springframework.data.jpa.repository.support.SimpleJpaRepository;import javax.persistence.EntityManager;
import java.io.Serializable;import static com.squirrel.specs.CustomerSpecs.*;public class CustomRepositoryImpl <T, ID extends Serializable>extends SimpleJpaRepository<T, ID> implementsCustomRepository<T,ID> {private  final EntityManager entityManager;public CustomRepositoryImpl(Class<T> domainClass, EntityManager entityManager) {super(domainClass, entityManager);this.entityManager = entityManager;}@Overridepublic Page<T> findByAuto(T example, Pageable pageable) {return findAll(byAuto(entityManager, example),pageable);}
}

package com.squirrel.support;import java.io.Serializable;
import javax.persistence.EntityManager;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.jpa.repository.support.JpaRepositoryFactory;
import org.springframework.data.jpa.repository.support.JpaRepositoryFactoryBean;
import org.springframework.data.jpa.repository.support.SimpleJpaRepository;
import org.springframework.data.repository.core.RepositoryInformation;
import org.springframework.data.repository.core.RepositoryMetadata;
import org.springframework.data.repository.core.support.RepositoryFactorySupport;public class CustomRepositoryFactoryBean<T extends JpaRepository<S, ID>, S, ID extends Serializable>extends JpaRepositoryFactoryBean<T, S, ID>{public CustomRepositoryFactoryBean(Class<? extends T> repositoryInterface) {super(repositoryInterface);}@Overrideprotected RepositoryFactorySupport createRepositoryFactory(EntityManager entityManager){return new CustomRepositoryFactory(entityManager);}private static class CustomRepositoryFactory extends JpaRepositoryFactory{public CustomRepositoryFactory(EntityManager entityManager){super(entityManager);}@Override@SuppressWarnings({"unchecked"})protected <T, ID extends Serializable> SimpleJpaRepository<?, ?> getTargetRepository(RepositoryInformation information, EntityManager entityManager){return  new CustomRepositoryImpl<T, ID>((Class<T>) information.getDomainType(), entityManager);}@Overrideprotected Class<?> getRepositoryBaseClass(RepositoryMetadata metadata){return CustomRepositoryImpl.class;}}
}

六、DAO

package com.squirrel.dao;import com.squirrel.entity.User;
import com.squirrel.support.CustomRepository;import java.util.List;public  interface UserDao extends CustomRepository<User, Long> {List<User> findByName(String name);}

七、controller

package com.squirrel.controller;import com.squirrel.dao.UserDao;
import com.squirrel.entity.User;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.PageRequest;
import org.springframework.data.domain.Sort;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;import java.util.List;@RestController
@RequestMapping("user")
public class UserController {private final Logger log = LoggerFactory.getLogger(UserController.class);@Autowiredprivate UserDao userDao;@RequestMapping("/getName")public List<User> getName (){log.info("访问/user/getName接口成功");List<User> users = userDao.findByName("哈哈");return users;}@RequestMapping("/insert")public String insert (){log.info("访问/user/insert接口成功");User user = new User();user.setName("是我");user.setAge(18);userDao.save(user);return "插入成功";}@RequestMapping("/sort")public List<User> sort (){log.info("访问/user/sort接口成功");List<User> users = userDao.findAll(new Sort(Sort.Direction.DESC,"age"));return users;}@RequestMapping("/page")public  Page<User> page (){log.info("访问/user/sort接口成功");Page<User> userPage = userDao.findAll(new PageRequest(10, 2));return userPage;}@RequestMapping("/auto")public Page<User> auto(User user){log.info("访问/user/auto接口成功");Page<User> userPage = userDao.findByAuto(user, new PageRequest(0, 10));return userPage;}
}

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【Spring Boot】整合JPA模糊分页查询

Spring Boot整合JPA

一、POM

二、配置文件

三、启动类

四、entity

五、分页模糊查询方法封装

六、DAO

七、controller

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