Java使用JDBC连接mysql、sqlserver、orcle数据库的baseDao类

mysql数据库的驱动jar包：mysql-connector-java-5.1.18-bin.jar

sqlserver数据库的驱动jar包：sqljdbc.jar

orcle数据库的驱动jar包：orcle*.jar,orcle根据数据库不同版本下载不同的驱动jar包

一定要有驱动jar包才能连接数据库

BaseDao类（驱动类）：

package com.dao;import java.sql.Connection;import java.sql.DriverManager;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.sql.SQLException;import java.util.List;public class BaseDao {/** * 数据库连接Connection */public Connection con;/** * 结果集ResultSet */public ResultSet rs;/** * JDBC连接数据库路径字符串 */private String url;/** * JDBC连接数据库账户 */private String user;/** * JDBC连接数据库密码 */private String password;/** * 数据库驱动加载类 */private String driver;/** * 无参构造函数 */public BaseDao(){//连接sqlserver数据库//this.setBaseDao("com.microsoft.sqlserver.jdbc.SQLServerDriver","jdbc:sqlserver://127.0.0.1;databasename=WebFileSystem","sa","NewPassword");    //连接mysql数据库this.setBaseDao("com.mysql.jdbc.Driver","jdbc:mysql://127.0.0.1/webfilesystem","root","root");    //连接orcle数据库this.setBaseDao("oracle.jdbc.driver.OracleDriver","jdbc:oracle://127.0.0.1/webfilesystem","root","root");}/** * 有参构造函数 */public BaseDao(String driver, String url, String user, String password){this.driver = driver;this.url = url;this.user = user;this.password = password;}/** * 设置JDBC连接数据库路径、账号、密码 */public void setBaseDao(String driver, String url, String user, String password){this.driver = driver;this.url = url;this.user = user;this.password = password;}/** * 获取数据库连接对象Connection */public Connection getConnection(){try {Class.forName(driver);con = DriverManager.getConnection(url,user,password);}catch (ClassNotFoundException e) {e.printStackTrace();}catch (SQLException e) {e.printStackTrace();}catch (Exception e) {e.printStackTrace();}return con;}/** * 关闭资源的函数 */public void closeAll(){if(rs != null){try {rs.close();} catch (SQLException e) {e.printStackTrace();}catch (Exception e) {e.printStackTrace();}}if(con != null){try {con.close();} catch (SQLException e) {e.printStackTrace();}catch (Exception e) {e.printStackTrace();}}}/** * 增加、删除、修改 */public int executeUpdate(String sql){int rows = 0;try {getConnection();PreparedStatement ps = con.prepareStatement(sql);rows = ps.executeUpdate();}catch (SQLException e) {e.printStackTrace();}catch (Exception e) {e.printStackTrace();}finally{closeAll();}return rows;}/** * 增加、删除、修改 */public int executeUpdate(String sql, Object[] pre){int rows = 0;try{getConnection();PreparedStatement ps = con.prepareStatement(sql);if(pre != null){for(int i = 0; i < pre.length; i++){ps.setObject(i+1, pre[i]);}}rows = ps.executeUpdate();}catch (SQLException e) {e.printStackTrace();}catch (Exception e) {e.printStackTrace();}finally{closeAll();}return rows;}/** * 增加、删除、修改 */public int executeUpdate(String sql, List<Object> pre){int rows = 0;try{getConnection();PreparedStatement ps = con.prepareStatement(sql);if(pre != null){for(int i = 0; i < pre.size(); i++){ps.setObject(i+1, pre.get(i));}}rows = ps.executeUpdate();}catch (SQLException e) {e.printStackTrace();}catch (Exception e) {e.printStackTrace();}finally{closeAll();}return rows;}/** * 查询多行多列数据到成员ResultSet对象 */public ResultSet executeQuery(String sql){try{getConnection();PreparedStatement ps = con.prepareStatement(sql);rs = ps.executeQuery();}catch (SQLException e) {e.printStackTrace();}catch (Exception e) {}return rs;}/** * 查询多行多列数据到成员ResultSet对象 */public ResultSet executeQuery(String sql, Object[] pre){try{getConnection();PreparedStatement ps = con.prepareStatement(sql);if(pre != null){for(int i = 0; i < pre.length; i++){ps.setObject(i+1, pre[i]);}}rs = ps.executeQuery();}catch (SQLException e) {e.printStackTrace();}catch (Exception e) {e.printStackTrace();}return rs;}/** * 查询多行多列数据到成员ResultSet对象 */public ResultSet executeQuery(String sql, List<Object> pre){try{getConnection();PreparedStatement ps = con.prepareStatement(sql);if(pre != null){for(int i = 0; i < pre.size(); i++){ps.setObject(i+1, pre.get(i));}}rs = ps.executeQuery();}catch (SQLException e) {e.printStackTrace();}catch (Exception e) {e.printStackTrace();}return rs;}}