BaseDao的封装

package com.lovo.dao;

import java.lang.reflect.Field;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

import com.lovo.po.PO;
import com.lovo.po.UserPO;
import com.lovo.util.DBUtil;

public class  BaseDao {

 // 连接对象
 protected Connection con;

 // 操作对象
 protected PreparedStatement pst;

 // 结果集对象
 protected ResultSet rs;

 // 得到连接的方法
 protected Connection getConnection() {

  return DBUtil.getConnection();
 }

 // 关闭连接的方法
 protected void close() {
  try {

   if (rs != null) {
    rs.close();
   }
   if (pst != null) {
    pst.close();
   }
   if (con != null) {
    con.close();
   }
  } catch (Exception e) {
   e.printStackTrace();
  }
 }

 // 查询的一种万能的方法，利用反射，参数是sql语句 类模板，值列表

 protected List getPoList(String sql, Class cla, List valueList) {
 
  List list = new ArrayList();
               con = this.getConnection();
  try {
           
   
   // 操作sql
   pst = con.prepareStatement(sql);

   // 如果valuelist不为空的话，则利用setObject方法设置占位符
   if (valueList != null) {

    for (int i = 0; i < valueList.size(); i++) {

     pst.setObject(i + 1, valueList.get(i));

    }

   }

   // 执行sql语句
   rs = pst.executeQuery();

   // 构建对象的list集合
   while (rs.next()) {

    // 得到对象的实例
    Object poObject = cla.newInstance();
                    PO po  = (PO)poObject;
    // 得到属性的集合
    Field[] field = cla.getDeclaredFields();
    for (int i = 0; i < field.length; i++) {

    
     // 得到所有的属性
     Field temp = field[i];

     // 去掉访问修饰 限制
     temp.setAccessible(true);

     // 得到属性名
     String fildName = temp.getName();

     // 将属性的值设置到po对象中,利用getObject方法得到数据库中的值
     temp.set(po, rs.getObject(fildName));
   
     

    }
    
     list.add(po);
   }

  } catch (Exception e) {

   e.printStackTrace();
  }

  return list;

 }

 

 

 // 增删改业务的封装。参数是sql和填充占位符用的 参数对象数组
   protected int executeUpdate(String sql, Object[] param) {
  int j = 0;
  // 建立连接
  con = this.getConnection();

  // 预编译sql
  try {
   pst = con.prepareStatement(sql);

   if (param != null) {

    for (int i = 0; i < param.length; i++) {
     // 设置占位符

     pst.setObject(i + 1, param[i]);
    }

   }

   j = pst.executeUpdate();

  } catch (Exception e) {

   e.printStackTrace();
  }

  return j;

 }

}

评论

2 楼 学会做人 2010-04-16  

谢谢指教！

1 楼 CodingMouse 2010-03-15  

你把参数列表 List valueList 和 Object[] param 改成 Object... 相信会好用些。

我也封装了一个持久化工具，调用方式为：

AbstractDAOFactory<AccountPOJO> factory = AbstractDAOFactory.newInstance();
IGenericsDAO<AccountPOJO> dao = factory.buildGenericsDAO();

List<AccountPOJO> list = dao.find(AccountPOJO.class,
Condition.valueOf("accountname", "like", "邓%"),
Condition.valueOf("email", "like", "[e-mail]"));
for (AccountPOJO account : list) {
    System.out.println(account);
}

------------

当开启控制台输出时，输出内容为：

[The current database connection pool size in 2010-03-15 21:35:20.265]：10
[The current database connection pool is opened in 2010-03-15 21:35:20.265]
[CmSdk4j Auto SQL Generator In 2010-03-15 21:35:20.39]
SELECT accountid, accountname, onlinecount, birthday, loginname, loginpassword, email, accountstate FROM account WHERE accountname like ? AND email like ?
------------------------------
[SQL Parameter List Information In 2010-03-15 21:35:20.453]
No：1
Type：java.lang.String
Value：邓%
------------------------------
[SQL Parameter List Information In 2010-03-15 21:35:20.468]
No：2
Type：java.lang.String
Value：[e-mail]
------------------------------
[ accountid = 1, accountname = 邓可可, onlinecount = 2203, birthday = 1984-12-26, loginname = CodingMouse, loginpassword = cmsdk4j, email = [e-mail], accountstate = true ]
[ accountid = 7, accountname = 邓丽君, onlinecount = 429, birthday = null, loginname = ChengCheng, loginpassword = chengchengpwd, email = [e-mail], accountstate = true ]
[The current database connection pool is closed in 2010-03-15 21:35:20.906]