1、DAO层
DAO层是接口层，故而需要使用【interface】修饰
源码如下：
package com.item.dao; import com.item.pojo.UserInfo; import java.util.List; public interface UserInfoDAO { /** * 查询所有用户信息 * @return */ public List<UserInfo> GetAll(); /** * 添加用户 * @param info * @return */ public boolean InsertUserInfo(UserInfo info); /** * 单个ID查询 * @param id * @return */ public UserInfo SelectById(int id); /** * 修改用户信息 * @param info * @return */ public boolean UpdateById(UserInfo info); /** * 根据id删除用户 * @param id * @return */ public boolean DeleteById(int id); }
2、DAOImpl层
DAOImpl属于实现层，故而通过【】实现DAO层对应接口即可
编码过程中可以看到注释也是很完整的。
源码如下：
package com.item.daoimpl; import com.item.dao.UserInfoDAO; import com.item.jdbc.FactoryDB; import com.item.pojo.UserInfo; import java.sql.Connection; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; import java.util.LinkedList; import java.util.List; public class UserInfoDAOImpl implements UserInfoDAO { Connection conn = null; PreparedStatement pre = null; ResultSet res = null; @Override public List<UserInfo> GetAll() { try { conn = FactoryDB.GetConnection(); pre = conn.prepareStatement("select * from userinfo"); res = pre.executeQuery(); List<UserInfo> list = new LinkedList<UserInfo>(); while (res.next()) { list.add(new UserInfo( res.getInt(1), res.getDate(2), res.getString(3), res.getString(4) )); } FactoryDB.Close(conn, pre, res); return list; } catch (SQLException e) { e.printStackTrace(); } return null; } @Override public boolean InsertUserInfo(UserInfo info) { try { conn = FactoryDB.GetConnection(); pre = conn.prepareStatement("INSERT INTO userinfo VALUES (0,NOW(),?,?);"); pre.setString(1, info.getUserName()); pre.setString(2, info.getIntroduce()); int isf = pre.executeUpdate(); FactoryDB.Close(conn, pre, res); return isf != -1; } catch (SQLException e) { e.printStackTrace(); } return false; } @Override public UserInfo SelectById(int id) { try { conn = FactoryDB.GetConnection(); pre = conn.prepareStatement("select * from userinfo where id=?"); pre.setInt(1, id); res = pre.executeQuery(); //判断查询结果是否为空 if (res.wasNull()) { return null; } UserInfo u=null; while (res.next()) { u = new UserInfo(res.getInt(1), res.getDate(2), res.getString(3), res.getString(4)); } FactoryDB.Close(conn, pre, res); return u; } catch (SQLException e) { e.printStackTrace(); } return null; } @Override public boolean UpdateById(UserInfo info) { try { conn = FactoryDB.GetConnection(); pre = conn.prepareStatement("update userinfo set userName=?,introduce=? where id=?"); pre.setString(1, info.getUserName()); pre.setString(2, info.getIntroduce()); pre.setInt(3, info.getId()); int isf = pre.executeUpdate(); FactoryDB.Close(conn, pre, res); return isf != -1; } catch (SQLException e) { e.printStackTrace(); } return false; } @Override public boolean DeleteById(int id) { try { conn = FactoryDB.GetConnection(); pre = conn.prepareStatement("delete from test.userinfo where id=?"); pre.setInt(1, id); int isf = pre.executeUpdate(); FactoryDB.Close(conn, pre, res); return isf != -1; } catch (SQLException e) { e.printStackTrace(); } return false; } }
到此DAO与DAOImpl层封装完毕。
