数据库连接池之ComboPooledDataSource

数据库的连接池有很多，今天来学习一下ComboPooledDataSource;

需要的jar包：

<dependency>
    <groupId>c3p0</groupId>
    <artifactId>c3p0</artifactId>
    <version>0.9.1.2</version>
</dependency>

因为是mysql数据库，所以还需要

<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>5.1.34</version>
</dependency>

第一种方式：不采用配置文件配置，纯java代码连接：

import com.mchange.v2.c3p0.ComboPooledDataSource;

import java.sql.Connection;


public class TestCombo{
    private ComboPooledDataSource dataSource;

    private TestCombo() {
        try {
            dataSource = new ComboPooledDataSource();
            dataSource.setUser(root);
            dataSource.setPassword(123456);
            dataSource.setJdbcUrl(jdbc:mysql://127.0.0.1:3306/test?useUnicode=true&characterEncoding=utf-8");
            dataSource.setDriverClass(com.mysql.jdbc.Driver);
            dataSource.setInitialPoolSize();
            dataSource.setAcquireIncrement();
            dataSource.setMinPoolSize();
            dataSource.setMaxPoolSize();
            dataSource.setMaxStatements();
            dataSource.setMaxIdleTime();
            dataSource.setIdleConnectionTestPeriod();
            dataSource.setAcquireRetryAttempts();

        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

  
    public Connection getConnection() {
        try {
            return dataSource.getConnection();
        } catch (Exception e) {
            throw new RuntimeException("can not get sms database connection  ", e);
        }
    }

}

第二种方式（配置文件）

配置文件：c3p0-config.xml 

名字必须为这个！

<c3p0-config>

<!-- 默认配置，如果没有指定则使用这个配置 -->

   <default-config>

<property name="driverClass">com.mysql.jdbc.Driver</property>

<property name="jdbcUrl">

<![CDATA[jdbc:mysql://127.0.0.1:3306/test?useUnicode=true&characterEncoding=UTF-8]]>

</property>

<property name="user">root</property>

<property name="password">1234</property>

<!-- 初始化池大小 -->

<property name="initialPoolSize">2</property>

<!-- 最大空闲时间 -->

<property name="maxIdleTime">30</property>

<!-- 最多有多少个连接 -->

<property name="maxPoolSize">10</property>

<!-- 最少几个连接 -->

<property name="minPoolSize">2</property>

<!-- 每次最多可以执行多少个批处理语句 -->

<property name="maxStatements">50</property>

</default-config> <!-- 命名的配置 -->

<named-config name="demo">

<property name="driverClass">com.mysql.jdbc.Driver</property>

<property name="jdbcUrl"><![CDATA[jdbc:mysql://127.0.0.1:3306/test?useUnicode=true&characterEncoding=UTF-8]]></property>

<property name="user">root</property>

<property name="password">1234</property>

<property name="acquireIncrement">5</property><!-- 如果池中数据连接不够时一次增长多少个 -->

<property name="initialPoolSize">100</property>

<property name="minPoolSize">50</property>

<property name="maxPoolSize">1000</property>

<property name="maxStatements">0</property>

<property name="maxStatementsPerConnection">5</property>

<!-- he's important, but there's only one of him -->

</named-config>

</c3p0-config>

代码中获取实例

ComboPooledDataSource pool = new ComboPooledDataSource();//空参，自动到classpath目录下面加载“c3p0-config.xml”配置文件---配置文件的存储位置和名称必须是这样，且使用“默认配置”

ComboPooledDataSource pool = new ComboPooledDataSource("demo");//加载“c3p0-config.xml”文件中定义的“demo”这个配置元素