java通用Hibernate DAO

Question

如果有人能帮忙，我将不胜感激

我的计划是有两层。一个是服务层，第二个是DAO层。服务层将执行业务逻辑，DAO层将执行CRUD数据操作

有两个名为Person和Order的休眠实体。这两个实体实现了BaseEntity接口。想在DAO层编写一个通用方法，这样它就可以接受任何实体

有没有关于如何编写通用dao方法的建议

@Entity
@Table(name = "PERSON")
public class Person implements BaseEntity, java.io.Serializable {

private int id;
private String firstName;

public Person() {
}

@Id
@Column(name = "PERSON_ID")
@GeneratedValue(strategy = GenerationType.AUTO)
public int getId() {
    return id;
}

public void setId(int id) {
    this.id = id;
}

@Column(name = "FIRST_NAME", nullable = false, length = 50)
public String getFirstName() {
    return firstName;
}

public void setFirstName(String firstName) {
    this.firstName = firstName;
}
}

---

@Entity
@Table(name = "PURCHASE_ORDER")
public class Order implements BaseEntity java.io.Serializable {

private int id;

public Order() {
}

@Id
@Column(name = "ORDER_ID")
@GeneratedValue(strategy = GenerationType.AUTO)
public int getId() {
    return id;
}

public void setId(int id) {
    this.id = id;
}

@Transient
@OneToMany(cascade = CascadeType.ALL, fetch = FetchType.EAGER)
public Set<OrderItem> getOrderItems() {
    return orderItems;
}

public void setOrderItems(Set<OrderItem> orderItems) {
    this.orderItems = orderItems;
}
}

您能否建议如何创建一个通用方法，该方法应将Person或Order实体作为输入参数

Answer 1

下面是编写通用获取方法的方法：

 public <T> T get(long id,Class<T> clazz) throws Exception{

            Session session = null;
            T t=null;
            try
            {
                session=getSessionFactory().openSession();
                t= (T) session.get(clazz.getCanonicalName(),id);
            }
            catch(Exception e)
            {
                throw e;
            }
                    finally{
                          if(session!=null) session.close();
                    }
            return t;
        }

忽略异常处理。使用自己的异常处理技术

Answer 2

让Person和Order子类化一个基本的DAO，让方法接受DAO