双向一对一外键关联annotationl配置

本文深入探讨了Java中实体类Husband和Wife之间的关联关系,通过使用JPA注解展示了如何实现一对多的关系映射。

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po类Husband.java

package com.hibernate.demo.po;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.OneToOne;
@Entity
public class Husband {
	private int id;
	private String name;
	private Wife wife;
	@Id
	@GeneratedValue
	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	@OneToOne
	@JoinColumn(name="wife_id")
	public Wife getWife() {
		return wife;
	}
	public void setWife(Wife wife) {
		this.wife = wife;
	}
	
	
}

 po类Wife

package com.hibernate.demo.po;

import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.OneToOne;

/**
 * 凡是双向外键关联,一定设置mappedBy
 * @author apprentice
 *
 */
@Entity
public class Wife {
	private int id;
	private String name;
	private Husband husband;
	
	@OneToOne(mappedBy="wife")	//Husband是主导
	public Husband getHusband() {
		return husband;
	}
	public void setHusband(Husband husband) {
		this.husband = husband;
	}
	@Id
	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
}

 

 

package com.kucun.Service; import java.io.Serializable; import java.lang.reflect.Field; import java.util.*; import java.util.stream.Collectors; import javax.persistence.EntityNotFoundException; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.dao.DataAccessException; import org.springframework.data.domain.Example; import org.springframework.data.domain.ExampleMatcher; import org.springframework.data.jpa.repository.JpaRepository; import org.springframework.stereotype.Service; import com.kucun.data.entity.*; import com.kucun.dataDo.*; /** * * * @ModelCoreReference [platform:/resource/KuCun2/.springDSL/com/kucun/Service/AppService/.properties.srv] */ @Service public class AppService { // 自动注入所有依赖 @Autowired private KucunRepository kucunRepository; @Autowired private DynamicRepositoryService repositoryService; @Autowired private EntityDependencyService dependencyService; /** * 获取所有实体类型的数据 * @return 包含所有实体数据的Map * * @ModelReference [platform:/resource/KuCun2/.springDSL/com/kucun/Service/AppService/getAllData%7B0d73352a-86ca-4239-9dd1-013b7e4b5c9e%7D/.properties.swoperation] */ public Information getAllData() { Map<String, Object> response = new HashMap<>(); repositoryService.getRepositoryNameMap().forEach((key, repo) -> response.put(key + "s", repo.findAll()) ); return Information.NewSuccess(response); } /** * 获取指定实体类型的所有数据 * @param entityName 实体名称 * @return 实体数据列表 * * @ModelReference [platform:/resource/KuCun2/.springDSL/com/kucun/Service/AppService/getEntityData%7Bb387e59c-3e7b-443a-a4ed-8fd7f30185f3%7D/.properties.swoperation] */ public Information getEntityData(String entityName) { JpaRepository<?, ?> repo = repositoryService.getJpaRepository(entityName); return Information.NewSuccess(repo.findAll()); } /** * 添加新实体 * @param entity 要添加的实体对象 * @return 添加结果 * * @ModelReference [platform:/resource/KuCun2/.springDSL/com/kucun/Service/AppService/addEntity%7Ba0d243e9-943a-4a3c-9b1c-babaa506fc76%7D/.properties.swoperation] */ public Information addEntity(Object entity) { try { // 处理关联字段 handleAssociations(entity); System.out.println("----------------------------------------------------------------------------"+entity); // 获取对应的Repository并保存 JpaRepository<Object, Serializable> repo = (JpaRepository<Object, Serializable>) repositoryService.getJpaRepository(entity.getClass()); //System.out.println(Information.NewSuccess(entity).DataJson()); Object savedEntity = repo.save(entity); System.out.println("----------------------------------------------------------------------------"+entity); // 如果是板材,初始化库存 if (savedEntity instanceof Bancai) { initializeKucunForBancai((Bancai) savedEntity); } return Information.NewSuccess(savedEntity); } catch (Exception ex) { return Information.Newfail(500, "创建失败: " + ex.getMessage(), null); } } /** * 更新实体 * @param entity 包含ID的实体对象 * @return 更新结果 * * @ModelReference [platform:/resource/KuCun2/.springDSL/com/kucun/Service/AppService/updateEntity%7B06eaa777-2f44-48d7-9e76-8881379b2a64%7D/.properties.swoperation] */ public Information updateEntity(Object entity) { if (entity == null) { return Information.Newfail(403, "参数为空", null); } try { // 获取ID字段 Field idField = entity.getClass().getDeclaredField("id"); idField.setAccessible(true); Object idValue = idField.get(entity); if (idValue == null) { return Information.Newfail(403, "ID为空", null); } // 获取Repository和现有实体 JpaRepository<Object, Serializable> repo = (JpaRepository<Object, Serializable>) repositoryService.getJpaRepository(entity.getClass()); Object existingEntity = repo.findById((Serializable) idValue) .orElseThrow(() -> new RuntimeException("实体不存在")); // 复制非空属性并保存 copyNonNullProperties(entity, existingEntity); return Information.NewSuccess(repo.save(existingEntity)); } catch (Exception ex) { return Information.Newfail(500, "更新失败: " + ex.getMessage(), null); } } /** * 删除实体 * @param entity 要删除的实体 * @return 删除结果 */ public Information deleteEntity(EntityBasis entity) { if (entity == null) { return Information.NewFail("删除对象不能为空"); } try { String entityName = entity.getClass().getSimpleName().toLowerCase(); JpaRepository<Object, Serializable> repo = (JpaRepository<Object, Serializable>) repositoryService.getJpaRepository(entityName); // 先加载完整实体(关步骤) Object managedEntity = repo.findById(entity.getId()) .orElseThrow(() -> new EntityNotFoundException("实体不存在")); System.out.println("// 获得实体"); if(entity instanceof Bancai) { Kucun k=kucunRepository.findByBancai((Bancai)entity); if(k!=null&&k.getShuliang()>0) { return Information.NewFail("库存不为零,无法删除"); } if(k!=null) kucunRepository.delete(k); } System.out.println("// 检查库存"); // 检查依赖关系 if (dependencyService.hasDependencies(entity.getClass(), entity.getId())) { return Information.NewFail("该记录已被引用,无法删除"); } System.out.println("// 检查依赖关系"); // 使用实体对象删除(触发级联操作) repo.delete(managedEntity); return Information.NewSuccess("删除成功"); } catch (Exception e) { return Information.NewFail("删除错误: " + e.getMessage()); } }/** * 动态查询实体 * @param entity 包含查询条件的实体对象 * @return 查询结果 */ public <T> Information queryEntity(T entity) { if (entity == null) { return Information.NewFail("查询参数不能为空"); } try { JpaRepository<T, ?> repo = (JpaRepository<T, ?>) repositoryService.getJpaRepository(entity.getClass()); Example<T> example = Example.of(entity, ExampleMatcher.matching() .withIgnoreNullValues() .withStringMatcher(ExampleMatcher.StringMatcher.CONTAINING)); return Information.NewSuccess(repo.findAll(example)); } catch (Exception e) { return Information.NewFail("查询失败: " + e.getMessage()); } } // ====================== 私有辅助方法 ====================== /** * 为板材初始化库存 * @param bancai 板材对象 */ private void initializeKucunForBancai(Bancai bancai) throws Exception { Kucun kucun = new Kucun(null, bancai, 0); bancai.setKucun(kucunRepository.save(kucun)); } /** * 处理实体关联关系 * @param entity 要处理的实体 */ private void handleAssociations(Object entity) throws Exception { for (Field field : entity.getClass().getDeclaredFields()) { field.setAccessible(true); Object value = field.get(entity); if (value == null) continue; // 处理 JPA 实体关联 if (value instanceof EntityBasis) { EntityBasis associated = (EntityBasis) value; JpaRepository<Object, Serializable> repo = (JpaRepository<Object, Serializable>) repositoryService.getJpaRepository(associated.getClass().getSimpleName().toLowerCase()); // 只处理已存在实体(不创建新关联) if (associated.getId() != null) { Object managedEntity = repo.findById(associated.getId()) .orElseThrow(() -> new Exception("关联实体不存在")); field.set(entity, managedEntity); } } // 处理集合关联 else if (value instanceof Collection) { List<Object> managedEntities = new ArrayList<>(); for (Object item : (Collection<?>) value) { if (item instanceof EntityBasis) { EntityBasis eb = (EntityBasis) item; JpaRepository<Object, Serializable> repo = (JpaRepository<Object, Serializable>) repositoryService.getJpaRepository(eb.getClass().getSimpleName().toLowerCase()); if (eb.getId() != null) { managedEntities.add(repo.findById(eb.getId()) .orElseThrow(() -> new RuntimeException("关联实体不存在"))); } } } if (!managedEntities.isEmpty()) { field.set(entity, managedEntities); } } } } 实现 @Autowired private DynamicRepositoryService repositoryService; @Autowired private EntityDependencyService dependencyService;这两个类 /** * 复制非空属性 * @param source 源对象 * @param target 目标对象 */ private void copyNonNullProperties(Object source, Object target) throws IllegalAccessException { for (Field field : source.getClass().getDeclaredFields()) { field.setAccessible(true); Object value = field.get(source); // 跳过关联字段和ID字段 if (value != null && !(value instanceof EntityBasis) && !(value instanceof Collection) && !field.getName().equals("id")) { try { Field targetField = target.getClass().getDeclaredField(field.getName()); targetField.setAccessible(true); targetField.set(target, value); } catch (NoSuchFieldException ignored) {} } } } }
06-21
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