连接池占满问题

测试类：

package com.test;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

import com.mchange.v2.c3p0.ComboPooledDataSource;

public class Test4 {
	public static void main(String[] args) {

		ComboPooledDataSource cpd = new ComboPooledDataSource();
		Connection conn = null;
		PreparedStatement ps = null;
		ResultSet rs = null;

		try {
			Connection conn1 = cpd.getConnection();
			Connection conn2 = cpd.getConnection();
			Connection conn3 = cpd.getConnection();
			Connection conn4 = cpd.getConnection();
			Connection conn5 = cpd.getConnection();
			System.out.println(conn1);
			System.out.println(conn2);
			System.out.println(conn3);
			System.out.println(conn4);
			System.out.println(conn5);
			Connection conn6 = cpd.getConnection();

		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}

//		try {
//			conn=cpd.getConnection();
//			ps=conn.prepareStatement("select * from u_p");
//			rs=ps.executeQuery();
//			while(rs.next()) {
//				System.out.println(rs.getInt("id")+"---"+rs.getString("username")+"---"+rs.getString("pw"));
//			}
//			
//			
//		} catch (SQLException e) {
//			// TODO Auto-generated catch block
//			e.printStackTrace();
//		}finally {
//			try {
//				JDBCUtil.release(rs, ps, conn);
//			} catch (Exception e) {
//				// TODO Auto-generated catch block
//				e.printStackTrace();
//			}
//		}

	}
}

c3p0-config.xml

<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/jiejie</property>
    <property name="user">root</property>
    <property name="password">root</property>
    
    <!-- 连接池参数 -->
    <property name="initialPoolSize">3</property>
    <property name="maxPoolSize">5</property>
    <property name="checkoutTimeout">3000</property>
  </default-config>
</c3p0-config>