反射泛型,Dao设计模型 (编码时需要用到)

Dao

package com.xiaofan.reflect;

import java.io.Serializable;

public interface Dao<T> {
    /**
     * 添加实体(Entity--Domain)数据到数据库中
     * @param t
     */
    void save(T t);
    /**
     * 修改数据库中的实体
     * @param t
     */
    void update(T t);
    /**
     * 根据主键删除记录
     * @param pk
     */
    void delete(Serializable pk);
    /**
     * 根据主键查询一条记录
     * @param pk
     * @return
     */
    T find(Serializable pk);
    
}

 DAOBase

package com.xiaofan.reflect;

import java.io.Serializable;
import java.lang.reflect.ParameterizedType;

import org.hibernate.Session;

public abstract class DAOBase<T> implements Dao<T> {
    private Session session;
    private Class clazz;
    //反射泛型
    public DAOBase(){
        Class clz = this.getClass();//具体的Dao实现类  com.xiaofan.reflect.BookDaoImpl
//        System.out.println(clz.getName());
        ParameterizedType pt = (ParameterizedType)clz.getGenericSuperclass();//  DAOBase<Book>
//        System.out.println(pt);
        clazz = (Class)pt.getActualTypeArguments()[0];// Book.class
//        System.out.println(clazz);
    }
    
    public void save(T t) {
        session.save(t);
    }

    public void update(T t) {
        session.update(t);
    }

    public void delete(Serializable pk) {
        T t = (T)session.get(clazz, pk);
        session.delete(t);
    }

    public T find(Serializable pk) {
        return (T)session.get(clazz, pk);
    }

}

BookDao

package com.xiaofan.reflect;

public interface BookDao extends Dao<Book>{
    /**
     * 根据条件查询
     * @param where
     */
    void queryByCondition(String where);
}

BookDaoImpl

package com.xiaofan.reflect;


public class BookDaoImpl extends DAOBase<Book> implements BookDao{
    
    public void queryByCondition(String where) {
        
    }

}

Book

package com.xiaofan.reflect;

public class Book {

}

CustomerDao

package com.xiaofan.reflect;

public interface CustomerDao extends Dao<Customer>{

}

CustomerDaoImpl

package com.xiaofan.reflect;


public class CustomerDaoImpl extends DAOBase<Customer> implements CustomerDao {
    
}

Customer

package com.xiaofan.reflect;

public class Customer {

}

Client

package com.xiaofan.reflect;

public class Client {

    public static void main(String[] args) {
        BookDao bDao = new BookDaoImpl();
        bDao.queryByCondition("condition");
        CustomerDao cDao = new CustomerDaoImpl();
        cDao.find(001);
    }

}