利用JDK5的泛型增强Dao基类

DAO:

import java.util.List;
import org.springframework.orm.ibatis.support.SqlMapClientDaoSupport;

import dao.GenericDAO;
import IDSetable;

public class GenericDAOIBatis<T, PK> extends SqlMapClientDaoSupport implements GenericDAO<T,PK> {
	
	protected String getTname(); {
		return "";
	}
	
	@SuppressWarnings("unchecked");
	public List<T> selectAll(); {
		return (List<T>); 
			getSqlMapClientTemplate();.queryForList("selectAll"+getTname();, null);;
	}

	public List<T> selectAtRange(PK id, int begin, int end); {
		
		// TODO Auto-generated method stub
		return null;
	}

	public void create(T obj); {
		Object result = getSqlMapClientTemplate();.insert("insert"+getTname();, obj);;
		if (result != null && obj instanceof IDSetable); {
			((IDSetable);obj);.setId(result);;
		}
	}

	@SuppressWarnings("unchecked");
	public T get(PK id); {
		return (T); getSqlMapClientTemplate();.queryForObject("get"+getTname();, id);;
	}

	/**
	 * @throws org.springframework.dao.DataAccessException
	 */
	public void update(T obj); {
		getSqlMapClientTemplate();.update("update"+getTname();, obj);;
	}

	public void delete(PK id); {
		getSqlMapClientTemplate();.delete("delete"+getTname();, id);;
	}

}

子Interface 和 Dao:

public interface TaskDAO extends GenericDAO<Task, Long> {

}

public class TaskDAOIBatis extends GenericDAOIBatis<Task, Long> implements TaskDAO {

	@Override
	protected String getTname(); {
		return "Task";
	}

}

public interface IDSetable {
	
	void setId(Object id);;

}

参考IBM developerWorks的创意：

package com.crackj2ee.dao;

import java.util.List;

import org.hibernate.Query;

public class DaoSupport<T> {

    private Class<T> type;

    @SuppressWarnings("unchecked")
    public T query(Long id) {
        try {
            Object obj = getSession().get(type, id);
            if(obj!=null)
                return (T)obj;
        }
        catch(Exception e) {
            throw new QueryException("查询失败", e);
        }
        throw new QueryException("指定的资源未找到，可能已被删除。");
    }

    public void save(T t) {
        getSession().save(t);
    }

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

}


我的主键是Long，可以很容易改成别的类型