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我在EJB3 有新的问题,JPA我的堆栈跟踪是:EJB3,JPA误差与多个结果从Query.getSingleResult()返回
Caused by: javax.persistence.NonUniqueResultException: More than one result was returned from Query.getSingleResult()
at org.eclipse.persistence.internal.jpa.EJBQueryImpl.throwNonUniqueResultException(EJBQueryImpl.java:1207)
at org.eclipse.persistence.internal.jpa.EJBQueryImpl.getSingleResult(EJBQueryImpl.java:722)
at com.DAO.CartDAO.checkUserID(CartDAO.java:47)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.glassfish.ejb.security.application.EJBSecurityManager.runMethod(EJBSecurityManager.java:1056)
at org.glassfish.ejb.security.application.EJBSecurityManager.invoke(EJBSecurityManager.java:1128)
at com.sun.ejb.containers.BaseContainer.invokeBeanMethod(BaseContainer.java:5292)
at com.sun.ejb.EjbInvocation.invokeBeanMethod(EjbInvocation.java:615)
at com.sun.ejb.containers.interceptors.AroundInvokeChainImpl.invokeNext(InterceptorManager.java:797)
at com.sun.ejb.EjbInvocation.proceed(EjbInvocation.java:567)
at com.sun.ejb.containers.interceptors.SystemInterceptorProxy.doAround(SystemInterceptorProxy.java:157)
at com.sun.ejb.containers.interceptors.SystemInterceptorProxy.aroundInvoke(SystemInterceptorProxy.java:139)
at sun.reflect.GeneratedMethodAccessor206.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at com.sun.ejb.containers.interceptors.AroundInvokeInterceptor.intercept(InterceptorManager.java:858)
at com.sun.ejb.containers.interceptors.AroundInvokeChainImpl.invokeNext(InterceptorManager.java:797)
at com.sun.ejb.co
我创建一个命令按钮用于添加物品到购物车,我写了一种方法添加项目到数据库,我检查是否userid和itemid!= null,项目数量将增加到1,这意味着当我有userid 1添加itemid 1到购物车,我的方法将检查如果存在的话,商品数量会在购物车表中添加1个商品数量,我可以用一个商品来完成,但是如果我将更多商品添加到购物车中,则意味着我添加了商品id到购物车表格中,然后添加更多数量itemid 1进入db它抛出异常多于一个结果。 。 。 我知道它不能同时有两个实例,但我不知道如何解决它? 请帮我
我addTocart方法
public void addtoCart(Items item){
this.items = item;
if(cartDAO.checkUserID(getMemberLoginController().getUser().getUserid()) != null &&
cartDAO.checkItemid(items.getItemid()) != null){
cart = cartDAO.checkUserID(getMemberLoginController().getUser().getUserid());
int updateQuantity = cart.getCartQuantity() + 1;
cart.setCartQuantity(updateQuantity);
// chuyen so luong sang kieu du lieu big decimal
java.math.BigDecimal bigQuantity = new java.math.BigDecimal(String.valueOf(updateQuantity));
// so tien cua san pham = so luong x don gia
BigDecimal updatePrice = items.getPrice().multiply(bigQuantity);
cart.setPrice(updatePrice);
cart = cartDAO.updateCart(cart);
}else if(cartDAO.checkUserID(getMemberLoginController().getUser().getUserid()) != null &&
cartDAO.checkItemid(items.getItemid()) == null){
cart = cartDAO.checkUserID(getMemberLoginController().getUser().getUserid());
cartPk.setUserid(getMemberLoginController().getUser().getUserid());
cartPk.setItemid(item.getItemid());
cart.setCartPK(cartPk);
cart.setCartQuantity(1);
cart.setPrice(item.getPrice());
cart = cartDAO.addCart(cart);
}else {
cartPk.setItemid(item.getItemid());
cartPk.setUserid(getMemberLoginController().getUser().getUserid());
cart.setCartPK(cartPk);
cart.setCartQuantity(1);
cart.setPrice(item.getPrice());
cart = cartDAO.addCart(cart);
}
}
我的select语句
@NamedQuery(name = "Cart.findByUserid", query = "SELECT c FROM Cart c WHERE c.cartPK.userid = :userid")
我checkuseridMethod
public Cart checkUserID(int id){
Cart cart = null;
try {
Query query = em.createNamedQuery("Cart.findByUserid");
query.setParameter("userid", id);
return (Cart) query.getSingleResult();
} catch (NoResultException e) {
return null;
}
}
非常感谢! :d – MYE 2010-10-24 18:42:59