简答c3p0配置

1.下载c3p0的jar文件和数据库连接的jar文件导入到工程

2.配置文件的信息

<c3p0-config>
  <!-- 使用默认的配置读取连接池对象 -->
  <default-config>
  	<!--  连接参数 -->
    <property name="driverClass">com.mysql.jdbc.Driver</property>
    <property name="jdbcUrl">jdbc:mysql://localhost:3306/test_db?useUnicode=true&characterEncoding=utf-8&autoReconnect=true&rewriteBatchedStatements=TRUE</property>
    <property name="user">root</property>
    <property name="password">88888888</property>
    
    <!-- 连接池参数 -->
    <property name="initialPoolSize">5</property>
    <property name="maxPoolSize">10</property>
    <property name="checkoutTimeout">3000</property>
  </default-config>

  <named-config name="otherc3p0">
    <!--  连接参数 -->
    <property name="driverClass">com.mysql.jdbc.Driver</property>
    <property name="jdbcUrl">jdbc:mysql://localhost:3306/test_db</property>
    <property name="user">root</property>
    <property name="password">88888888</property>

    <!-- 连接池参数 -->
    <property name="initialPoolSize">5</property>
    <property name="maxPoolSize">8</property>
    <property name="checkoutTimeout">1000</property>
  </named-config>
</c3p0-config>

 3.连接的代码配置

//        1.创建数据库连接池对象
        DataSource dataSource = new ComboPooledDataSource();
//        DataSource dataSource = new ComboPooledDataSource("otherc3p0");
        Connection connection = null;
        PreparedStatement statement = null;
        ResultSet resultSet = null;
//        2.创建数据库的连接池
        try {
            connection = dataSource.getConnection();
            statement = connection.prepareStatement("select * from students where id = ?");
            statement.setInt(1,1);
            resultSet = statement.executeQuery();
            while (resultSet.next()){
                System.out.println(resultSet.getString("name"));
            }
            System.out.println(connection);
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            try {
                resultSet.close();
                statement.close();
                connection.close();

            } catch (SQLException e) {
                e.printStackTrace();
            }
        }