c3p0连接池 & JdbcUtils

一、引入jar包

二、java代码

 1     @Test
 2     public void testXML() throws Exception {
 3         // 创建c3p0连接池核心工具类
 4         // 自动加载src下c3p0的配置文件【c3p0-config.xml】
 5         ComboPooledDataSource dataSource = new ComboPooledDataSource();// 使用默认的配置
 6         PreparedStatement pstmt = null;
 7
 8         // 获取连接
 9         Connection con = dataSource.getConnection();
10         for (int i=1; i<11;i++){
11             String sql = "insert into employee(empName,dept_id) values(?,?)";
12             // 执行更新
13             pstmt = con.prepareStatement(sql);
14             pstmt.setString(1, "Rose" + i);
15             pstmt.setInt(2, 1);
16             pstmt.executeUpdate();
17         }
18         pstmt.close();
19         // 关闭
20         con.close();
21
22     }

三、配置文件（c3p0-config.xml）

 1 <c3p0-config>
 2     <default-config>
 3         <property name="jdbcUrl">jdbc:mysql://localhost:3306/jdbc_demo
 4         </property>
 5         <property name="driverClass">com.mysql.jdbc.Driver</property>
 6         <property name="user">root</property>
 7         <property name="password">root</property>
 8         <property name="initialPoolSize">3</property>
 9         <property name="maxPoolSize">6</property>
10         <property name="maxIdleTime">1000</property>
11     </default-config>
12
13
14     <named-config name="oracle_config">
15         <property name="jdbcUrl">jdbc:mysql://localhost:3306/jdbc_demo</property>
16         <property name="driverClass">com.mysql.jdbc.Driver</property>
17         <property name="user">root</property>
18         <property name="password">root</property>
19         <property name="initialPoolSize">3</property>
20         <property name="maxPoolSize">6</property>
21         <property name="maxIdleTime">1000</property>
22     </named-config>
23
24
25 </c3p0-config>

四、JdbcUtils(使用连接池)

 1 public class JdbcUtil {
 2
 3     //初始化连接池
 4     private static DataSource dataSource;
 5
 6     //静态代码块初始化连接池资源，只执行一次
 7     static{
 8         dataSource = new ComboPooledDataSource();
 9     }
10
11     /**
12      * 返回连接对象
13      */
14     public static Connection getConnection() {
15         try {
16             return dataSource.getConnection();
17         } catch (SQLException e) {
18             throw new RuntimeException(e);
19         }
20     }
21
22     /**
23      * 关闭
24      */
25     public static void closeAll(Connection con, Statement stmt, ResultSet rs) {
26         try {
27             if (rs != null) {
28                 rs.close();  // 快速异常捕获 Alt + shift + z
29                 rs = null;   // 建议垃圾回收期回收资源
30             }
31             if (stmt != null) {
32                 stmt.close();
33                 stmt = null;
34             }
35             if (con != null && !con.isClosed()) {
36                 con.close();
37                 con = null;
38             }
39         } catch (SQLException e) {
40             throw new RuntimeException(e);
41         }
42     }
43 }