我有一个非常复杂的方法addOrder()，它在一个事务中包含多个查询，还有一个会话：
简单地没有业务逻辑，它看起来像这样：
DBservice
public boolean addOrder( List<Items> item, String custumerName, double sum){
try{
session = sesinfactory.openSession();
tx = session.beginTransaction();
....
Dao dao = new Dao(session);
Custumer custumer = dao.getCustomerByName(custumerName);
List<Items> tocheckItems = dao.getItems(item);
...
dao.updateItems(itemsToUpdate);
if (custumer != null) {
if (custumer.getCoins() >= sum) {
for (Items items : item) {
custumer.addItem(items);
}
}
}
dao.updateCustomerForOrder(custumer);
tx.commit();
}
.....
finally {
if (session != null){
session.close();
}
}
}
道
public class Dao {
private Session session;
public Dao(Session session) {
this.session = session;
}
public void updateItems(List<Items> itemsName) {
int i=0;
for (Items s : itemsName) {
session.update(s);
if( i % 50 == 0 ) { // Same as the JDBC batch size
//flush a batch of inserts and release memory:
session.flush();
session.clear();
}
i++;
}
}
public void updateCustomerForOrder(Custumer custumer) {
session.update(custumer);
}
}
执行方法addOrder()我在
updateCustomerForOrder()，调试模式显示传入此方法的session和customer个对象
不是空的，所以我有点困惑什么是错的？
完整的堆栈跟踪：
java.lang.NullPointerException
at org.hibernate.type.descriptor.java.AbstractTypeDescriptor.extractHashCode(AbstractTypeDescriptor.java:84)
at org.hibernate.type.AbstractStandardBasicType.getHashCode(AbstractStandardBasicType.java:216)
at org.hibernate.type.AbstractStandardBasicType.getHashCode(AbstractStandardBasicType.java:220)
at org.hibernate.type.EntityType.getHashCode(EntityType.java:391)
at org.hibernate.type.ComponentType.getHashCode(ComponentType.java:258)
at org.hibernate.engine.spi.EntityKey.generateHashCode(EntityKey.java:76)
at org.hibernate.engine.spi.EntityKey.<init>(EntityKey.java:71)
at org.hibernate.internal.AbstractSessionImpl.generateEntityKey(AbstractSessionImpl.java:327)
at org.hibernate.engine.internal.StatefulPersistenceContext.getDatabaseSnapshot(StatefulPersistenceContext.java:311)
at org.hibernate.engine.internal.ForeignKeys.isTransient(ForeignKeys.java:255)
at org.hibernate.event.internal.AbstractSaveEventListener.getEntityState(AbstractSaveEventListener.java:521)
at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.performSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:100)
at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.onSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:90)
at org.hibernate.internal.SessionImpl.fireSaveOrUpdate(SessionImpl.java:684)
at org.hibernate.internal.SessionImpl.saveOrUpdate(SessionImpl.java:676)
at org.hibernate.engine.spi.CascadingActions$5.cascade(CascadingActions.java:235)
at org.hibernate.engine.internal.Cascade.cascadeToOne(Cascade.java:350)
at org.hibernate.engine.internal.Cascade.cascadeAssociation(Cascade.java:293)
at org.hibernate.engine.internal.Cascade.cascadeProperty(Cascade.java:161)
at org.hibernate.engine.internal.Cascade.cascadeCollectionElements(Cascade.java:379)
at org.hibernate.engine.internal.Cascade.cascadeCollection(Cascade.java:319)
at org.hibernate.engine.internal.Cascade.cascadeAssociation(Cascade.java:296)
at org.hibernate.engine.internal.Cascade.cascadeProperty(Cascade.java:161)
at org.hibernate.engine.internal.Cascade.cascade(Cascade.java:118)
at org.hibernate.engine.internal.Cascade.cascade(Cascade.java:86)
at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.cascadeOnUpdate(DefaultSaveOrUpdateEventListener.java:375)
at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.performUpdate(DefaultSaveOrUpdateEventListener.java:349)
at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.entityIsDetached(DefaultSaveOrUpdateEventListener.java:244)
at org.hibernate.event.internal.DefaultUpdateEventListener.performSaveOrUpdate(DefaultUpdateEventListener.java:55)
at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.onSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:90)
at org.hibernate.internal.SessionImpl.fireUpdate(SessionImpl.java:739)
at org.hibernate.internal.SessionImpl.update(SessionImpl.java:731)
at org.hibernate.internal.SessionImpl.update(SessionImpl.java:726)
at org.CoinsShop.DataBase.Dao.updateCustomerForOrder(Dao.java:129)
at org.CoinsShop.DataBase.DbService.addOrder(DbService.java:286)
at org.CoinsShop.bussinessLayer.BusineesLayer.handleOrder(BusineesLayer.java:61)
at org.CoinsShop.bussinessLayer.BusineesLayer$handleOrder.call(Unknown Source)
at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:48)
at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:113)
at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:117)
at org.CoinsShop.DataBase.DbServiceTest.addOrder2Test(DbServiceTest.groovy:337)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:497)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:27)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:69)
at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:234)
at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:74)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:497)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:144)
UPD。
@Entity
@Table(name="Items")
public class Items implements Serializable,Comparable<Items> {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(name="id")
private Long id;
@Column(name="name", unique = true)
private String name;
@Column(name="price")
private double price;
@Column(name="count")
private int count;
@OneToMany(fetch = FetchType.EAGER,mappedBy = "item", cascade = CascadeType.ALL,orphanRemoval = true)
List<Order> orders = new LinkedList<Order>();
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
Items items = (Items) o;
return name.equals(items.name);
}
@Override
public int hashCode() {
int result;
long temp;
result = id != null ? id.hashCode() : 0;
result = 31 * result + name.hashCode();
temp = Double.doubleToLongBits(price);
result = 31 * result + (int) (temp ^ (temp >>> 32));
result = 31 * result + count;
result = 31 * result + (orders != null ? orders.hashCode() : 0);
return result;
}
@Override
public int compareTo(Items o) {
return getName().compareTo(o.getName());
}
}
答案 0 :(得分：0)
这篇文章帮助https://stackoverflow.com/a/8576809/5526080
我需要添加到客户更新的项目，而不是原点
dao.updateItems(itemsToUpdate);
if (custumer != null) {
if (custumer.getCoins() >= sum) {
for (Items items : itemsToUpdate) {
custumer.addItem(itemsToUpdate);
}
}
}
dao.updateCustomerForOrder(custumer);
tx.commit();
否则项目哈希码是不同的，正如我所理解的那样