jdbc连接数据库BaseDao类.doc

package com.dao.impl;import java.sql.*;import javax.servlet.jsp.jstl.sql.Result;import javax.servlet.jsp.jstl.sql.ResultSupport;public class BaseDao private static final String DRIVER = oracle.jdbc.driver.OracleDriver;private static final String URL = jdbc:oracle:thin:localhost:1521:orcl2;private static final String USRENAME = zhangsan;private static final String PASSWORD = 123;/ 仅作为返回ResultSet查询时使用private Connection conn = null;private PreparedStatement pst = null;private ResultSet rs = null;/* * 返回连接 * * return Connection */private Connection getConnection() try Class.forName(DRIVER);conn = DriverManager.getConnection(URL, USRENAME, PASSWORD); catch (Exception e) e.printStackTrace();return conn;/* * 返回ResultSet,需每次实例化一个BaseDao,然后调用CloseALL方法关闭对象 * * param sql * 预编译的 SQL 语句 * param param * 预编译的 SQL 语句中的？参数的字符串数组 * */public ResultSet executeQuerySQL(String sql, Object. param) try conn = getConnection(); / 得到数据库连接pst = conn.prepareStatement(sql); / 得到PreparedStatement对象if (param != null) for (int i = 0; i param.length; i+) pst.setObject(i + 1, parami); / 为预编译sql设置参数rs = pst.executeQuery(); / 执行SQL语句 catch (Exception e) e.printStackTrace(); / 处理ClassNotFoundException异常return rs;/* * 添，删，改 * * param sql * param param * return */public int executeUpdate(String sql, Object. param) conn = getConnection();int row = 0;try pst = conn.prepareStatement(sql);if (param != null) for (int i = 0; i param.length; i+) pst.setObject(i + 1, parami);row = pst.executeUpdate(); catch (SQLException e) / TODO Auto-generated catch blocke.printStackTrace(); finally closeALL(null, pst, conn);return row;/* * 返回Result * * param sql * param param * return */public Result executeQuery(String sql, Object. param) Connection conn = null;PreparedStatement pst = null;ResultSet rs = null;Result rst = null;try conn = getConnection(); / 得到数据库连接pst = conn.prepareStatement(sql); / 得到PreparedStatement对象if (param != null) for (int i = 0; i param.length; i+) pst.setObject(i + 1, parami); / 为预编译sql设置参数rs = pst.executeQuery(); / 执行SQL语句rst = ResultSupport.toResult(rs);/ 关闭连接对象rs.close();pst.close();conn.close(); catch (Exception e) e.printStackTrace(); / 处理ClassNotFoundException异常return rst;/* * 查询单个值,如count,sum,max,avg等 * * param sql * param param * return */public Object executeScalar(String sql, Object. param) Connection conn = getConnection();PreparedStatement pst = null;ResultSet rs = null;Object obj = null;try pst = conn.prepareStatement(sql);if (param != null) for (int i = 0; i param.length; i+) pst.setObject(i + 1, parami);rs = pst.executeQuery();obj = rs.getObject(1); catch (SQLException e) e.printStackTrace(); finally closeALL(null, pst, conn);return obj;/ 关闭ResultSet查询时的对象public void closeALL() try if (rs != null)rs.close();if (pst != null)pst.close();if (conn != null)conn.close(); catch (SQLException e) / TODO Auto-generated catch blocke.printStackTrace();/* * 关闭连接 * * param conn * Connection */public void closeALL(ResultSet rs, Statement pst, Connection conn) try i