java 数据库连接工具类

package com.elink.services;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

/**
* @author lucher
* 本类为连接各种数据库的工具类，包括sqlserver、mysql、oracle的连接，以及关闭连接方法
* 该类一般配合SQLUtil使用
*/
public class DBUtil {

// sqlserver 驱动
private static final String SQLSERVER_DRIVER = "com.microsoft.sqlserver.jdbc.SQLServerDriver";

// 数据库地址url 前面的为固定写法，后面的分别为ip地址：端口号,数据库名
//	private static final String SQLSERVER_URL = "jdbc:microsoft:sqlserver://localhost:1433;databaseName=WM";  //用微软的jar包（3个）的情况
private static final String SQLSERVER_URL = "jdbc:sqlserver://127.0.0.1:1433;databaseName=NewMedicineDatabase";  //用普通jar包（1个）的时候

private static final String SQLSERVER_USERNAME = "sa";// sqlserver 数据库用户名
private static final String SQLSERVER_PASSWORD = "1qazxsw2";// sqlserver 数据库密码

/**
* 获取SQLSERVER数据库连接
* @return 数据库的连接
*/
public static Connection getSQLSERVERConnection() {

Connection conn = null;
try {
//自动创建驱动程序的实例且自动调用DriverManager来注册它
Class.forName(SQLSERVER_DRIVER);
conn = DriverManager.getConnection(SQLSERVER_URL, SQLSERVER_USERNAME, SQLSERVER_PASSWORD);
System.out.println(conn);
} catch (ClassNotFoundException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

return conn;
}

// mysql 驱动
private static final String MYSQL_DRIVER = "com.mysql.jdbc.Driver";

// 数据库地址url 前面的为固定写法，后面的分别为ip地址：端口号,数据库名
private static final String MYSQL_URL = "jdbc:mysql://localhost:3306/dossier";

private static final String MYSQL_USERNAME = "admin";// mysql 数据库用户名
private static final String MYSQL_PASSWORD = "admin";// mysql 数据库密码

/**
* 获取MYSQL数据库连接
* @return 数据库的连接
*/
public static Connection getMYSQLConnection() {

Connection conn = null;
try {
//自动创建驱动程序的实例且自动调用DriverManager来注册它
Class.forName(MYSQL_DRIVER);
conn = DriverManager.getConnection(MYSQL_URL, MYSQL_USERNAME, MYSQL_PASSWORD);
} catch (ClassNotFoundException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

return conn;
}

// oracle驱动
private static final String ORACLE_DRIVER = "oracle.jdbc.driver.OracleDriver";

// 数据库地址url 前面的为固定写法，后面的分别为ip地址：端口号,数据库名
private static final String ORACLE_URL = "jdbc:oracle:thin:@localhost:1521:dababase";

private static final String ORACLE_USERNAME = "admin";// oracle 数据库用户名
private static final String ORACLE_PASSWORD = "admin";// oracle 数据库密码

/**
* 获取ORACLE数据库连接
* @return 数据库的连接
*/
public static Connection getORACLEConnection() {

Connection conn = null;
try {
//自动创建驱动程序的实例且自动调用DriverManager来注册它
Class.forName(ORACLE_DRIVER);
conn = DriverManager.getConnection(ORACLE_URL, ORACLE_USERNAME, ORACLE_PASSWORD);
} catch (ClassNotFoundException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

return conn;
}

/**
* 关闭数据库连接,针对有参数的查询情况
* @param rs 返回的查询结果
* @param pstmt
* @param conn
*/
public static void closeConn(ResultSet rs, PreparedStatement pstmt, Connection conn) {
if (rs != null) {
try {
rs.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
if (pstmt != null) {
try {
pstmt.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
if (conn != null) {
try {
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}

/**
* 关闭数据库连接重载，针对没有参数的查询情况
* @param rs
* @param ps
* @param conn
*/
public static void closeConn(ResultSet rs, Statement ps, Connection conn) {
if (rs != null) {
try {
rs.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
if (ps != null) {
try {
ps.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
if (conn != null) {
try {
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}

/**
* 关闭数据库连接重载，针对更新语句情况
* @param pstmt
* @param conn
*/
public static void closeConn(PreparedStatement pstmt, Connection conn) {
if (pstmt != null) {
try {
pstmt.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
if (conn != null) {
try {
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}

/**
* 关闭数据库连接重载，针对同时执行两条条更新语句
* @param pstmt1
* @param pstmt2
* @param conn
*/
public static void closeConn(PreparedStatement pstmt1, PreparedStatement pstmt2, Connection conn) {
if (pstmt1 != null) {
try {
pstmt1.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
if (pstmt2 != null) {
try {
pstmt2.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
if (conn != null) {
try {
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
}

package util;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;

/**
* @author lucher
* 本类为sql工具类，包括sql无参、有参查询，以及sql更新语句方法
* 该类一般配合DBUtil使用，只是列举了常用的方法，具体使用时稍加修改
*/
public class SQLUtil {

// 无参数的查询语句
private static final String sql1 = "select * from company";

// 有参数的查询语句
private static final String sql2 = "select password from company where name=?";

// 更新语句
private static final String sql3 = "update company set password=? where name=?";

// 删除语句，同时执行
private static final String sql4 = "delete from user where id=?";
private static final String sql5 = "delete from userInfo where id=?";

/**
* 无参数查询,返回类型据情况稍加修改,以sqlserver为例，其他类似
*
* @return 所有记录的名字的list
*/
public static List<String> getAll() {

Connection conn = null;
Statement ps = null;
ResultSet rs = null;
List<String> info = new ArrayList<String>();

try {
conn = DBUtil.getSQLSERVERConnection();
ps = conn.createStatement();
rs = ps.executeQuery(sql1);

while (rs.next()) {
info.add(rs.getString("name")); // 根据具体情况定
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} finally {
DBUtil.closeConn(rs, ps, conn);
}
return info;
}

/**
* 有参数查询,返回类型据情况稍加修改,以sqlserver为例，其他类似
*
* @param name
* @param password
* @return 返回指定名字和密码的记录list
*/
public static List<String> getAllByNP(String name, String password) {

Connection conn = null;
PreparedStatement pstmt = null;
ResultSet rs = null;
List<String> info = new ArrayList<String>();

try {
conn = DBUtil.getSQLSERVERConnection();
pstmt = conn.prepareStatement(sql1);
pstmt.setString(1, name);
pstmt.setString(2, password);
rs = pstmt.executeQuery();
while (rs.next()) {
info.add(rs.getString(1));
info.add(rs.getString(2));
}

} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} finally {
DBUtil.closeConn(rs, pstmt, conn);
}

return info;
}

/**
* 更新类方法,只执行一条的情况,以sqlserver为例，其他类似
* @param name
* @param password
* @return 执行更新的结果
*/
public static boolean updatePasswordByName(String name, String password) {

int result = 0;
boolean flag = true;

Connection conn = null;
PreparedStatement pstmt = null;

try {
conn = DBUtil.getSQLSERVERConnection();

pstmt = conn.prepareStatement(sql3);
pstmt.setString(1, password);
pstmt.setString(2, name);

result = pstmt.executeUpdate();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} finally {
DBUtil.closeConn(pstmt, conn);
}

if (result == 0) {
flag = false;
}
return flag;
}

/**
* 更新类方法,同时执行两条的情况,以sqlserver为例，其他类似
* @param id
* @return 执行删除的结果
*/
public static boolean deleteById(int id) {

int result1 = 0;
int result2 = 0;
boolean flag = true;

Connection conn = null;
PreparedStatement pstmt1 = null;
PreparedStatement pstmt2 = null;

try {
conn = DBUtil.getSQLSERVERConnection();
conn.setAutoCommit(false);

pstmt1 = conn.prepareStatement(sql4);
pstmt1.setInt(1, id);

pstmt2 = conn.prepareStatement(sql5);
pstmt2.setInt(1, id);

result1 = pstmt1.executeUpdate();
result2 = pstmt2.executeUpdate();

conn.commit();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
try {
conn.rollback();
} catch (SQLException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
} finally {
DBUtil.closeConn(pstmt1, pstmt2, conn);
}

if (result1 == 0 || result2 == 0) {
flag = false;
}
return flag;
}
}