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我尝试显示数据库中的数据，但出现 500 错误页面：javax.ejb.EJBException。我不明白为什么它不起作用。也许我的 Bean 错了？请帮我。

Glassfish 日志中的警告：警告：警告：EJB5184：在调用 EJB SearchBean 期间发生系统异常，方法：public java.util.Collection com.stark.logic.SearchBean.searchByNumber(int) 

@Entity
@Table(name = "buy")
@XmlRootElement
@NamedQueries({
@NamedQuery(name = "Buy.findAll", query = "SELECT b FROM Buy b"),
@NamedQuery(name = "Buy.findByIdBuy", query = "SELECT b FROM Buy b WHERE b.idBuy = :idBuy"),
@NamedQuery(name = "Buy.findByNumberBuy", query = "SELECT b FROM Buy b WHERE b.numberBuy = :numberBuy")})
public class Buy implements Serializable {
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Basic(optional = false)
@Column(name = "id_buy")
private Integer idBuy;
@Basic(optional = false)
@NotNull
@Column(name = "number_buy")
private int numberBuy;
@OneToOne(cascade = CascadeType.ALL, mappedBy = "buy")
private Product product;
@OneToOne(cascade = CascadeType.ALL, mappedBy = "buy")
private Client client;
//getters & setters

EJB 豆：

@Stateless
@LocalBean
public class SearchBean {

@PersistenceUnit
EntityManagerFactory emf;
EntityManager em;

public Collection searchByNumber(int number){
    em = emf.createEntityManager();
    Query searchQuery = em.createNamedQuery("Buy.findByNumberBuy");
    searchQuery.setParameter("number_buy", number);
    List list = new ArrayList();
    list = searchQuery.getResultList();

    return list;
}
}

小服务程序：

@EJB
private SearchBean searchBean;


@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws    ServletException, IOException {
    PrintWriter out = response.getWriter();
    response.setContentType("text/html;charset=UTF-8");

    String num = request.getParameter("number");
    int number = Integer.parseInt(num);
    List list = new ArrayList();
    list = (List) searchBean.searchByNumber(number);
    Iterator it = list.iterator();
    while(it.hasNext()){
        Buy buy = (Buy) it.next();
        out.println(buy.getProduct());
    }
}
4

1 回答 1

1

@NamedQuery 和 setParameter() 方法中的参数名称必须相等：

searchQuery.setParameter("numberBuy", number);
于 2013-05-30T14:47:07.480 回答