package java4.connection;

import java.beans.PropertyVetoException;
import java.sql.Connection;
import java.sql.SQLException;

import org.junit.Test;

import com.mchange.v2.c3p0.ComboPooledDataSource;

public class C3P0Test {
	// 方式一：
	@Test
	public void testGetConnection() throws Exception{
		// 获取 C3p0 数据库连接池
		ComboPooledDataSource cpds = new ComboPooledDataSource();
		cpds.setDriverClass("com.mysql.cj.jdbc.Driver");
		cpds.setJdbcUrl("jdbc:mysql://localhost:3306/test");
		cpds.setUser("root");
		cpds.setPassword("abc123");
		
		// 通过设置相关的参数，对数据库连接池进行管理
		// 设置初始时数据库连接池中的连接数
		cpds.setInitialPoolSize(10);
		Connection conn = cpds.getConnection();
		System.out.println(conn);
		
	}
	
	// 方式二：使用配置文件
	@Test
	public void testGetConnection1() throws Exception{
		ComboPooledDataSource cpds = new ComboPooledDataSource("helloc3p0");
		Connection conn = cpds.getConnection();
		System.out.println(conn);
		
	}
}

<?xml version="1.0" encoding="UTF-8"?>
<c3p0-config>
	<named-config name="helloc3p0">
		<!-- 提供获取连接的 4 个基本信息 -->
		<property name="driverClass">com.mysql.cj.jdbc.Driver</property>
		<property name="jdbcUrl">jdbc:mysql:///test</property>
		<property name="user">root</property>
		<property name="password">abc123</property>
		
		<!-- 进行数据库连接池管理的基本信息 -->
		<!-- 当数据库连接池中的连接数不够时，c3p0 一次性向数据库服务器申请的连接数 -->
		<property name="acquireIncrement">5</property>
		<!-- c3p0 数据库连接池中初始化时的连接数 -->
		<property name="initialPoolSize">10</property>
		<!-- c3p0 数据库连接池维护的最少连接数 -->
		<property name="minPoolSize">10</property>
		<!-- c3p0 数据库连接池维护的最多的连接数 -->
		<property name="maxPoolSize"></property>
		<!-- c3p0 数据库连接池最多维护的 Statement 的个数 -->
		<property name="maxStatements">50</property>
		<!-- 每个连接中最多可以使用的 Statement 的个数 -->
		<property name="maxStatementPerConnection">2</property>
	</named-config>
</c3p0-config>

package java4.connection;
import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.util.Properties;
import javax.sql.DataSource;
import org.apache.commons.dbcp.BasicDataSourceFactory;
import org.junit.Test;
/*


测试 DBCP 的数据库连接池技术
*/
public class DBCPTest {
// 使用配置文件
@Test
public void testGetConnection1() throws Exception{
Properties pros = new Properties();
<span class="hljs-type">InputStream</span> <span class="hljs-variable">is</span> <span class="hljs-operator">=</span> ClassLoader.getSystemClassLoader().getResourceAsStream(<span class="hljs-string">"dbcp.properties"</span>);
pros.load(is);
<span class="hljs-type">DataSource</span> <span class="hljs-variable">source</span> <span class="hljs-operator">=</span> BasicDataSourceFactory.createDataSource(pros);
<span class="hljs-type">Connection</span> <span class="hljs-variable">conn</span> <span class="hljs-operator">=</span> source.getConnection();
System.out.println(conn);

}
}

driverClassName=com.mysql.cj.jdbc.Driver
url=jdbc:mysql:///test
username=root
password=abc123

initialSize=10

package java4.connection;
import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.util.Properties;
import javax.sql.DataSource;
import org.junit.Test;
import com.alibaba.druid.pool.DruidDataSourceFactory;
/*


Druid 数据库连接池
*/
public class DruidTest {
@Test
public void getConnection() throws Exception{
Properties pros = new Properties();
InputStream is = ClassLoader.getSystemClassLoader().getResourceAsStream("druid.properties");
pros.load(is);
<span class="hljs-type">DataSource</span> <span class="hljs-variable">source</span> <span class="hljs-operator">=</span> DruidDataSourceFactory.createDataSource(pros);
<span class="hljs-type">Connection</span> <span class="hljs-variable">conn</span> <span class="hljs-operator">=</span> source.getConnection();
System.out.println(conn);

}
}

url=jdbc:mysql:///test
username=root
password=abc123
driverClassName=com.mysql.cj.jdbc.Driver

initialSize=10
maxActive=10