dao.java

一个可以存储和打印成绩单的系统

package org.minjey.cjsjk.dao;
import java.util.HashMap;
import java.sql.Connection;

public abstract class Dao {

	private static Dao dao = null;
	
	public static Dao getDao(){
		if(dao == null) {
			dao = new DaoImpl();
		}
		return dao;
	}
	
	public static Dao getDao(Connection conn){
		return new DaoImpl(conn);
	}
	
	public abstract Connection getConnection();
	
	public abstract HashMap<Integer, Object> loadall(Class cla);
	public abstract HashMap<Integer, Object> load(Class cla, Object fobj);	//利用外键查找
	public abstract Object load(Class cla, Integer id);
	public abstract void update(Object obj);
	public abstract Object save(Object obj);
	public abstract Integer delete(Object obj);
}