Java 在JPA双向@OnetoMany关系中,当我更新父实体时,子实体在数据库中被删除
当我将my OrphanRemoving=true更改为false时,实体不会被删除,但在更新父实体后不会加载到json文件中。下面是我的代码。 模型类别: Market.java:Java 在JPA双向@OnetoMany关系中,当我更新父实体时,子实体在数据库中被删除,java,jpa-2.0,Java,Jpa 2.0,当我将my OrphanRemoving=true更改为false时,实体不会被删除,但在更新父实体后不会加载到json文件中。下面是我的代码。 模型类别: Market.java: package main.java.model; import java.io.Serializable; import java.util.ArrayList; import java.util.List; import javax.persistence.*; import javax.xml.bi
package main.java.model;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.List;
import javax.persistence.*;
import javax.xml.bind.annotation.XmlRootElement;
import org.codehaus.jackson.annotate.JsonIgnoreProperties;
@XmlRootElement(name="somename")
@Entity
@JsonIgnoreProperties(ignoreUnknown=true)
@Table(name = "market")
@SecondaryTable(name="product",pkJoinColumns=@PrimaryKeyJoinColumn(name="market_id"))
@NamedQuery(name = "findMarket",
query = "SELECT distinct m FROM Market m, Product p where m.id = p.market_id")
public class Market implements Serializable{
public List<Product> getProducts() {
return products;
}
public void setProducts(List<Product> products) {
this.products = products;
}
private static final long serialVersionUID = 1L;
@Column(name = "market_name")
private String market_name;
@Id
@GeneratedValue(strategy = GenerationType.SEQUENCE)
private int id;
@Column(name = "Online_Market_Accessibility")
private String oma;
@OneToMany(mappedBy="market", cascade=CascadeType.ALL, orphanRemoval=false)
@JoinColumn(name="id", nullable=false)
private List<Product> products = new ArrayList<>();
public Market()
{
}
public Market(String market_name,int id, String oma)
{
this.market_name = market_name;
this.id = id;
this.oma = oma;
}
public String getMarket_name() {
return market_name;
}
public void setMarket_name(String market_name) {
this.market_name = market_name;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getOma() {
return oma;
}
public void setOma(String oma) {
this.oma = oma;
}
@Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + id;
result = prime * result + ((market_name == null) ? 0 : market_name.hashCode());
result = prime * result + ((oma == null) ? 0 : oma.hashCode());
return result;
}
@Override
public boolean equals(Object obj) {
if (this == obj)
return true;
if (obj == null)
return false;
if (getClass() != obj.getClass())
return false;
Market other = (Market) obj;
if (id != other.id)
return false;
if (market_name == null) {
if (other.market_name != null)
return false;
} else if (!market_name.equals(other.market_name))
return false;
if (oma == null) {
if (other.oma != null)
return false;
} else if (!oma.equals(other.oma))
return false;
return true;
}
@Override
public String toString() {
return "[market_name:"+ market_name + ", id:" + id +", oma:"+oma+"]";
}
}
这是我的dao实现
package main.java.services;
import java.util.List;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;
import javax.persistence.Query;
import main.java.dao.MarketDao;
import main.java.model.Market;
public class MarketService implements MarketDao{
EntityManagerFactory emf = Persistence.createEntityManagerFactory("myPU");
EntityManager em = emf.createEntityManager();
public List<Market> getAllMarkets(){
Query query = em.createNamedQuery("findMarket");
List<Market> m = query.getResultList();
return m;
}
public void updateMarket(int id, String market_name, Market market) {
em.getTransaction().begin();
Query query = em.createQuery("UPDATE Market SET market_name=:market_name WHERE id=:id");
query.setParameter("id", id);
query.setParameter("market_name", market_name);
em.merge(market);
em.getTransaction().commit();
}
public void deleteMarket(int id) {
Market market = em.find(Market.class, id);
if(null != market) {
em.remove(market);
}
}
public void addMarket(Market market) {
em.getTransaction().begin();
em.persist(market);
em.getTransaction().commit();
}
}
]
更新后的JSON文件:
[
{
"id": 2,
"market_name": "SmartPhones",
"oma": "Yes",
"products": [
{
"product_id": 4,
"product_name": "Apple",
"market_id": 2
},
{
"product_id": 5,
"product_name": "Samsung",
"market_id": 2
}
]
},
{
"id": 3,
"market_name": "Pharmaceuticals",
"oma": null,
"products": [
{
"product_id": 6,
"product_name": "Ranbaxy",
"market_id": 3
}
]
},
{
"id": 1,
"market_name": "Airline Travels",
"oma": null,
"products": []
},
{
"id": 4,
"market_name": "Baked Good",
"oma": null,
"products": [
{
"product_id": 7,
"product_name": "Cake",
"market_id": 4
}
]
}
]
但是,数据存在于数据库中。当我重新启动服务器时,它已加载
这是我的控制器:
@Transactional
@Path("/json/market")
public class MarketContoller {
MarketService ms = new MarketService();
@GET
@Path("/get")
@Produces(MediaType.APPLICATION_JSON)
public List<Market> listAllMarket(){
return ms.getAllMarkets();
}
@PUT
@Path("/put/{id}")
@Consumes(MediaType.APPLICATION_JSON)
@Produces(MediaType.APPLICATION_JSON)
public Response update(@PathParam("id") int id, @PathParam("market_name") String market_name, Market market) {
String result = "Market updated " + market;
ms.updateMarket(id, market_name);
return Response.status(201).entity(result).build();
}
@DELETE
@Path("{id}")
public void delete(@PathParam("id") int id) {
ms.deleteMarket(id);
}
@POST
@Path("/post")
@Consumes(MediaType.APPLICATION_JSON)
@Produces(MediaType.APPLICATION_JSON)
public Response createMarketInJSON(Market market) {
String result = "Market created " + market;
ms.addMarket(market);
return Response.status(201).entity(result).build();
}
}
@Transactional
@路径(“/json/market”)
公共级市场控制员{
MarketService ms=新的MarketService();
@得到
@路径(“/get”)
@产生(MediaType.APPLICATION_JSON)
公共列表列表所有市场(){
返回getAllMarkets女士();
}
@放
@路径(“/put/{id}”)
@使用(MediaType.APPLICATION_JSON)
@产生(MediaType.APPLICATION_JSON)
公共响应更新(@PathParam(“id”)int-id、@PathParam(“market\u name”)字符串market\u name,market-market){
字符串结果=“市场更新”+市场;
updateMarket女士(id、市场名称);
返回Response.status(201).entity(result.build();
}
@删除
@路径(“{id}”)
public void delete(@PathParam(“id”)int-id){
市场女士(id);
}
@职位
@路径(“/post”)
@使用(MediaType.APPLICATION_JSON)
@产生(MediaType.APPLICATION_JSON)
公众响应createMarketInJSON(市场){
字符串结果=“市场创建”+市场;
addMarket女士(市场);
返回Response.status(201).entity(result.build();
}
}
我不知道你的控制器是什么样子,但那里有点乱七八糟。
因为您在更新期间覆盖了市场,所以至少id是正确的。所以试试这个:
public void updateMarket(int id, String market_name) {
em.getTransaction().begin();
Market market = em.find(Market.class, id);
if(null != market) {
market.setMarket_name(market_name);
em.merge(market);
}
em.getTransaction().commit();
}
我已经解决了这个问题。我对更新代码做了一点修改:
public void updateMarket(int id, String market_name, Market market) {
em.getTransaction().begin();
Query query = em.createQuery("UPDATE Market SET market_name=:market_name WHERE id=:id");
query.setParameter("id", id);
query.setParameter("market_name", market_name);
query.executeUpdate();
em.merge(market);
em.getTransaction().commit();
}
updateMarket方法中的查询根本不使用。您所要做的就是合并传入的市场对象。那个物体是从哪里来的?我假设您是从传入的json创建它的。如果传入的json不包含所有相关产品,那么当您合并它时,持久化市场将不再包含这些关系。但是,传入的json包含所有相关产品。但是当我合并它时,持久化的市场不再包含这些关系。这可能是我使用的代码的重复,现在,产品没有被删除,但市场名称在数据库中设置为null
public void updateMarket(int id, String market_name) {
em.getTransaction().begin();
Market market = em.find(Market.class, id);
if(null != market) {
market.setMarket_name(market_name);
em.merge(market);
}
em.getTransaction().commit();
}
public void updateMarket(int id, String market_name, Market market) {
em.getTransaction().begin();
Query query = em.createQuery("UPDATE Market SET market_name=:market_name WHERE id=:id");
query.setParameter("id", id);
query.setParameter("market_name", market_name);
query.executeUpdate();
em.merge(market);
em.getTransaction().commit();
}