public final class ConnectManager{

    private static ConnectManager connect = null;

    private ComboPooledDataSource ds = null;

    private final ReentrantLock lock;

    private ConnectManager() {
        lock = new ReentrantLock();
        ds = new ComboPooledDataSource();
        try {
            ds.setDriverClass(GetProperInfo.getProperName(DRIVERCLASS));
        } catch (PropertyVetoException e) {
            e.printStackTrace();
        }
        ds.setJdbcUrl(GetProperInfo.getProperName(JDBC_URL));
        ds.setUser(GetProperInfo.getProperName(JDBC_USER));
        ds.setPassword(GetProperInfo.getProperName(JDBC_PASSWORD));
        ds.setIdleConnectionTestPeriod(GetProperInfo
                .getIntProper(CONNECTIONTESTPERIOD)); // <!--每60秒检查所有连接池中的空闲连接。Default:
        // 0 -->
        ds.setInitialPoolSize(GetProperInfo.getIntProper(INITIALPOOLSIZE)); // <!--初始化时获取三个连接，取值应在minPoolSize与maxPoolSize之间。Default:
        // 3
        // -->
        ds.setMaxIdleTime(GetProperInfo.getIntProper(MAXIDLETIME));// <!--最大空闲时间,60秒内未使用则连接被丢弃。若为0则永不丢弃。Default:
        // 0 -->
        ds.setMaxPoolSize(GetProperInfo.getIntProper(MAXPOOLSIZE));// !--连接池中保留的最大连接数。Default:
        // 15 -->

        System.out.println("database info:");
        System.out
                .println("driver=" + GetProperInfo.getProperName(DRIVERCLASS));
        System.out.println("url=" + GetProperInfo.getProperName(JDBC_URL));
    }

    public static synchronized ConnectManager getInstance() {
        if (connect == null) {
            connect = new ConnectManager();
        }
        return connect;
    }

    public final Connection getConn() throws SQLException {
        final ReentrantLock lock = this.lock;
        lock.lock();
        try {
            return ds.getConnection();
        } finally {
            lock.unlock();
        }
    }

    @Override
    protected void finalize() throws Throwable {
        DataSources.destroy(ds); // 关闭datasource
        super.finalize();
    }
}

------解决方案--------------------
2)我来回答一下。
一般C3P0不会单独使用的，而在Spring中配置，所以没事，不需要知道配置文件叫什么名字。
XML code

<context:property-placeholder location="classpath:c3p0_2.properties" />

<bean id="dataSource"  
    class="com.mchange.v2.c3p0.ComboPooledDataSource"  
    destroy-method="close">  
    <property name="driverClass" value="${jdbc.driverClass}" />  
    <property name="jdbcUrl" value="${jdbc.url}" />  
    <property name="user" value="${jdbc.username}" />  
    <property name="password" value="${jdbc.password}" />  
    <property name="minPoolSize" value="${c3p0.minPoolSize}" />  
    <property name="maxPoolSize" value="${c3p0.maxPoolSize}" />  
    <p