以前呢,我們是通過DriverManager這個類來的得到Connection物件的。

現在我們通過DataSource來得到Connection，

其餘的都是一樣的東西，

先上DataSource得到Connection的程式碼。

在這之前，先將db.properties配置檔案的內容考進來

jdbc.datasource=com.mchange.v2.c3p0.ComboPooledDataSource
jdbc.driverClass=com.mysql.jdbc.Driver
jdbc.jdbcUrl=jdbc:mysql://localhost:3306/test
jdbc.user=root
jdbc.password=
jdbc.maxPoolSize=100
jdbc.minPoolSize=2
jdbc.initialPoolSize=2
jdbc.acquireIncrement=2
jdbc.maxStatements=1000
jdbc.maxIdleTime=300
jdbc.checkoutTimeout=5000
 

package org.test;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.Properties;

import javax.sql.DataSource;

import org.apache.commons.beanutils.BeanUtils;

public class JdbcDataSourceTest
{
	private static DataSource dataSource;

	private static Connection connection;

	private static PreparedStatement ps;

	private static ResultSet rs;

	public static void main(String[] args) throws Exception
	{

		
		
		Properties properties = new Properties();

		//從指定的配置檔案載入資料到properties中
		properties.load(JdbcDataSourceTest.class.getClassLoader().getResourceAsStream("db.properties"));

		
		/**
		 * properties其中一條記錄是這樣的
		 * jdbc.datasource=com.mchange.v2.c3p0.ComboPooledDataSource
		 * 將前面的jdbc.去掉在重新裝入一個Properties中
		 */
		Properties dbProperties = new Properties();

		for (Object key : properties.keySet())
		{
			String temp = (String) key;

			if (temp.startsWith("jdbc."))
			{
				String name = temp.substring(5);

				dbProperties.put(name, properties.getProperty(temp));

			}
		}

		//列出dbProperties中的所有屬性
		dbProperties.list(System.out);
		
		System.out.println("==============================================");

		//從廠商提供的DataSource實現中載入其物件
		dataSource = (DataSource) Class.forName(properties.getProperty("jdbc.datasource")).newInstance();

		
		//將dbProperties屬性中的內容加入到dataSource物件中
		BeanUtils.populate(dataSource, dbProperties);

		
		
		connection = dataSource.getConnection();

		ps = connection.prepareStatement("select * from test");

		rs = ps.executeQuery();

		while (rs.next())
		{
			System.out.println(rs.getString(1));
		}
	}
}
 

再來就是上以前通過DriverManager來得到Connection的程式碼

package org.test;

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

public class JdbcTest
{
	
	private static Connection connection ;
	
	private static PreparedStatement ps ;
	
	private static ResultSet rs  ;
	
	static 
	{
		try
		{
			Class.forName("com.mysql.jdbc.Driver");
		}
		catch (ClassNotFoundException e)
		{
			e.printStackTrace();
		}
		
		
	}
	
	public static void main(String[] args) throws Exception
	{
		connection = DriverManager.getConnection("jdbc:mysql://localhost:3306/test","root","");
		
		ps = connection.prepareStatement("select * from test");
		
		rs = ps.executeQuery();
		
		while (rs.next())
		{
			System.out.println(rs.getString(1));
		}
	}
}