1.动态插入
package com.example.springbootjpa.entity;import lombok.AllArgsConstructor;
import lombok.Builder;
import lombok.Data;
import lombok.NoArgsConstructor;
import org.hibernate.annotations.DynamicInsert;
import org.springframework.data.jpa.domain.support.AuditingEntityListener;import javax.persistence.*;/*** @author chenye* 2020-0313*/
//使用JPA注解配置映射关系
@Entity //告诉JPA这是一个实体类（和数据表映射的类）
@Table(name = "sys_user") //@Table来指定和哪个数据表对应;如果省略默认表名就是user；
@Data
@NoArgsConstructor
@Builder
@AllArgsConstructor
@DynamicInsert
@EntityListeners(AuditingEntityListener.class)
public class User {/*** 自增主键*/@Id@GeneratedValue(strategy = GenerationType.IDENTITY)private Integer id;@Column(name = "name", length = 50)private String name;/*** 省略默认列名就是属性名*/@Column(length = 50)private String email;}关键注解：
@DynamicInsert@EntityListeners(AuditingEntityListener.class)2.重写save（修改）：
package com.example.springbootjpa.repository;import org.springframework.beans.BeanUtils;
import org.springframework.beans.BeanWrapper;
import org.springframework.beans.BeanWrapperImpl;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.jpa.repository.support.JpaEntityInformation;
import org.springframework.data.jpa.repository.support.SimpleJpaRepository;
import org.springframework.util.StringUtils;import javax.persistence.EntityManager;
import javax.transaction.Transactional;
import java.beans.PropertyDescriptor;
import java.util.HashSet;
import java.util.Set;@SuppressWarnings(value = "all")
public class JpaRepositoryReBuild<T, ID> extends SimpleJpaRepository<T, ID> {private final JpaEntityInformation<T, ?> entityInformation;private final EntityManager em;@Autowiredpublic JpaRepositoryReBuild(JpaEntityInformation<T, ?> entityInformation, EntityManager entityManager) {super(entityInformation, entityManager);this.entityInformation = entityInformation;this.em = entityManager;}/*** 通用save方法 ：新增/选择性更新*/@Override@Transactionalpublic <S extends T> S save(S entity) {// 获取IDID entityId = (ID) this.entityInformation.getId(entity);T managedEntity;T mergedEntity;if (entityId == null) {em.persist(entity);mergedEntity = entity;} else {managedEntity = this.findById(entityId).get();if (managedEntity == null) {em.persist(entity);mergedEntity = entity;} else {BeanUtils.copyProperties(entity, managedEntity, getNullProperties(entity));em.merge(managedEntity);mergedEntity = managedEntity;}}return entity;}/*** 获取对象的空属性*/private static String[] getNullProperties(Object src) {// 1.获取BeanBeanWrapper srcBean = new BeanWrapperImpl(src);// 2.获取Bean的属性描述PropertyDescriptor[] pds = srcBean.getPropertyDescriptors();// 3.获取Bean的空属性Set<String> properties = new HashSet<>();for (PropertyDescriptor propertyDescriptor : pds) {String propertyName = propertyDescriptor.getName();Object propertyValue = srcBean.getPropertyValue(propertyName);if (StringUtils.isEmpty(propertyValue)) {srcBean.setPropertyValue(propertyName, null);properties.add(propertyName);}}return properties.toArray(new String[0]);}
}3.启动类
package com.example.springbootjpa;import com.example.springbootjpa.repository.JpaRepositoryReBuild;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.autoconfigure.domain.EntityScan;
import org.springframework.data.jpa.repository.config.EnableJpaAuditing;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;/*** 启动类** @author chenye* @date 2020-0313*/
@EnableJpaAuditing
@SpringBootApplication
@EnableJpaRepositories(value = {"com.example.springbootjpa.repository"},repositoryBaseClass = JpaRepositoryReBuild.class)//最好添加
@EntityScan(basePackages = {"com.example.springbootjpa.entity"})//最好添加
public class SpringbootJpaApplication {public static void main(String[] args) {SpringApplication.run(SpringbootJpaApplication.class, args);}}
关键注释：
EnableJpaRepositories 扫描的repository包
repositoryBaseClass 重写的save类
EnableJpaAuditing 使@EntityListeners(AuditingEntityListener.class) 生效