jdbc连接数据库

 1 package com.lt.grtg.util;
 2 
 3 import java.io.IOException;
 4 import java.io.InputStream;
 5 import java.sql.Connection;
 6 import java.sql.DriverManager;
 7 import java.sql.PreparedStatement;
 8 import java.sql.ResultSet;
 9 import java.sql.SQLException;
10 import java.util.Properties;
11 
12 public class DBUtil {
13     
14     /**
15      * 连接URL
16      */
17     private static String url;
18     /**
19      * 数据库连接用户名
20      */
21     private static String username;
22     /**
23      * 数据库连接密码
24      */
25     private static String password;
26 
27     static{
28         //加载数据库配置文件
29         InputStream inputStream = 
30                 DBUtil.class.getClassLoader().getResourceAsStream(properties文件路径);
31         Properties properties = new Properties();
32         try {
33             properties.load(inputStream);
34             url = properties.getProperty("url");
35             username = properties.getProperty("username");
36             password = properties.getProperty("password");
37             Class.forName(properties.getProperty("driver"));
38         } catch (IOException e) {
39             e.printStackTrace();
40             throw new RuntimeException("加载db.properties文件失败");
41         } catch (ClassNotFoundException e) {
42             e.printStackTrace();
43             throw new RuntimeException("未找到db.properties文件中driver属性配置的数据库驱动文件");
44         }
45     }
46     
47     /**
48      * 获取数据库连接
49      * @return Connection    数据库连接
50      * @throws SQLException 数据库连接异常
51      */
52     public static Connection getConnection() throws SQLException {
53         return DriverManager.getConnection(url, username, password);
54     }
55     
56     /**
57      * 关闭数据库连接
58      * @param resultSet    结果集
59      * @param preparedStatement    
60      * @param connection 数据库连接
61      */
62     public static void closeConnection(ResultSet resultSet,
63             PreparedStatement preparedStatement,Connection connection){
64         try {
65             //按顺序关闭JDBC对象：resultSet、preparedStatement、connection
66             if (resultSet != null) {
67                 resultSet.close();
68             }
69             if (preparedStatement != null) {
70                 preparedStatement.close();
71             }
72             if (connection != null) {
73                 connection.close();
74             }
75         } catch (SQLException e) {
76             e.printStackTrace();
77             throw new RuntimeException("关闭数据库连接失败");
78         }
79     }
80     
81 }