tomcat配置数据源

最近想搞清楚什么是“连接池”，在网上查了相关资料，貌似要跟“服务器”中配置，

 

 

1、首先在WebRoot/META-INF目录下面建立一个context.xml配置文件，内容如下

<?xml version="1.0" encoding="UTF-8"?><Context><WatchedResource>WEB-INF/web.xml</WatchedResource><Resource name="myoracle" auth="Container" type="javax.sql.DataSource"driverClassName="oracle.jdbc.OracleDriver" url="jdbc:oracle:thin:@localhost:1521:orcl"username="huangbiao" password="huangbiao" maxActive="200" maxIdle="10" maxWait="5000" /></Context>

 

2、启动tomcat服务器（如果启动失败，可能原因是没有驱动，需要在tomcat的lib目录下面放驱动包）

 

3、在servlet中得到得到数据源，操作数据库

 

package hb.servlet.dbpool;import java.io.IOException;import java.io.PrintWriter;import java.sql.Connection;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.sql.SQLException;import javax.naming.InitialContext;import javax.naming.NamingException;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import javax.sql.DataSource;import org.apache.log4j.Logger;public class ConnectDB extends HttpServlet {public static Logger log = Logger.getLogger(ConnectDB.class);public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {this.doPost(request, response);}public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {log.info("发送请求成功");try {InitialContext ic = new InitialContext();DataSource ds = (DataSource)ic.lookup("java:comp/env/myoracle");Connection conn = ds.getConnection();String sql = "select * from goods where GOODSNAME=?";PreparedStatement pre = conn.prepareStatement(sql);pre.setString(1, "7001");ResultSet rs = pre.executeQuery();while(rs.next()){ log.info(rs.getString(1)); log.info(rs.getString(2)); log.info(rs.getInt(3)); log.info(rs.getString(4)); log.info(rs.getString(5));}if(rs != null){log.info("关闭rs正常");rs.close();}if(pre != null){log.info("关闭pre正常");pre.close();}if(conn != null){log.info("关闭conn正常");conn.close();}PrintWriter pw = response.getWriter();String result = "操作数据库OK";pw.write(new String(result.getBytes("utf-8"),"ISO-8859-1"));pw.flush();} catch (NamingException e) {log.error("获取连接池异常");e.printStackTrace();} catch (SQLException e) {log.error("操作数据库失败");e.printStackTrace();}}}

 

 

在这里我有一些不明白的地方：

1、这种方式算是“使用连接池”吗

2、conn.close()这种方式关闭了是断开了数据源吗

请路过的高手指点一二