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 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 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;

}

}