java 数据库连接工厂

 1 package cc.whoisit;
 2 
 3 import java.io.FileInputStream;
 4 import java.sql.Connection;
 5 import java.sql.DriverManager;
 6 import java.util.Properties;
 7 
 8 /**
 9  * @author 
10  * 读取数据库配置文件
11  */
12 public class DBConnUtil {
13     private static Properties prop;
14     /**
15      * 配置文件名
16      */
17     private static final String configureFileName = "config.properties";
18     
19     /**
20      * 获取数据库连接
21      * @param dbName 数据库名，与config.properties文件中的配置一至
22      * @return 数据库连接
23      * @throws Exception IOException，  ClassNotFoundException， SQLException
24      */
25     public static Connection getConnection(String dbName) throws Exception {
26         if(prop == null){
27             prop = new Properties();
28             prop.load(new FileInputStream(configureFileName));
29             String dbDriver = prop.getProperty("dbDriver");
30             Class.forName(dbDriver);
31         }
32         
33         String url = prop.getProperty(dbName);
34         Connection conn = DriverManager.getConnection(url);
35         return conn;
36     }
37 }

 1 package cc.whoisit;
 2 
 3 import java.sql.Connection;
 4 
 5 /**
 6  * @author
 7  * 数据库连接工厂
 8  */
 9 public class DBFactory {
10     /**
11      * 获取测试库连接
12      * @return 数据库连接
13      * @throws Exception IOException, ClassNotFoundException,SQLException
14      */
15     public static Connection getTestConnect() throws Exception {
16         Connection conn = DBConnUtil.getConnection("testDBRead");
17         return conn;
18     }
19 }

1 #Mysql
2 dbDriver=com.mysql.jdbc.Driver
3 testDBRead=jdbc:mysql://127.0.0.1:3306/test?user=root&password=&useUnicode=true&characterEncoding=UTF-8&allowMultiQueries=true

 1 package cc.whoisit;
 2 
 3 import java.sql.Connection;
 4 import java.sql.ResultSet;
 5 import java.sql.Statement;
 6 
 7 public class Test {
 8 
 9     /**
10      * @param args
11      */
12     public static void main(String[] args) {
13         // TODO Auto-generated method stub
14         try {
15             Connection conn = DBFactory.getTestConnect();
16             String sql = "SELECT id, username, passwd FROM `user` LIMIT 100;";
17             // statement用来执行SQL语句
18             Statement statement = conn.createStatement();
19             ResultSet result = statement.executeQuery(sql);
20             while (result.next()) {
21                 System.out.println("==========");
22                 System.out.println(result.getInt("id"));
23                 System.out.println(result.getString("username"));
24                 System.out.println(result.getString("passwd"));
25             }
26 
27             if (!conn.isClosed()) {
28                 conn.close();
29             }
30 
31         } catch (Exception e) {
32             // TODO: handle exception
33             e.printStackTrace();
34         }
35     }
36 }