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利用myeclipse配置数据库连接池
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作为一个习惯使用myeclipse的人来说,即使是数据库连接池也肯定是用ide配置了.
下面说一下用数据库连接池的配置.
1 创建工程.不多说了.
2 添加数据库连接程序驱动包.直接放到lib目录下即可
3 配置context.xml文件
<?xml version="1.0" encoding="UTF-8"?>
<Context debug="" reloadable="true">
<Resource
name="jdbc/mysql"
auth="Container"
type="javax.sql.DataSource"
maxActive=""
maxIdle=""
maxWait=""
username="root"
password=""
driverClassName="com.mysql.jdbc.Driver"
url="jdbc:mysql://localhost:3306/pos?autoReconnect=true" />
</Context>
解释：
name="jdbc/mysql" //连接名，jndi中使用。具在JSP中用<sql:query var="rs" dataSource="jdbc/mysql">调用，servlet用 DataSource ds = (DataSource)ctx.lookup("java:comp/env/jdbc/mysql");调用。这里是tomcat的格式，不同的服务器可能有所不同。 auth="Container"
type="javax.sql.DataSource"
maxActive=""
maxIdle=""
maxWait=""
username="root" //mysql的用户名
password="" //mysql的用户密码，我这里是空
driverClassName="com.mysql.jdbc.Driver" //驱动类名，一般确定
url="jdbc:mysql://localhost:3306/javatest?autoReconnect=true" //javatest是mysql中要使用的数据库名
4 配置web.xml文件
<resource-ref>
<description>DB Connection</description>
<res-ref-name>jdbc/mysql</res-ref-name>
<res-type>javax.sql.DataSource</res-type>
<res-auth>Container</res-auth>
</resource-ref>
如此就完成了数据库的连接.我喜欢用servlet,给出一个servlet的测试代码:
package com.pos.test; import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException; import javax.naming.Context;
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; public class TEST extends HttpServlet
{ /**
* Constructor of the object.
*/
public TEST()
{
super();
} /**
* Destruction of the servlet. <br>
*/
public void destroy()
{
super.destroy(); // Just puts "destroy" string in log
// Put your code here
} /**
* The doGet method of the servlet. <br>
*
* This method is called when a form has its tag value method equals to get.
*
* @param request the request send by the client to the server
* @param response the response send by the server to the client
* @throws ServletException if an error occurred
* @throws IOException if an error occurred
*/
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException
{ doPost(request,response);
} /**
* The doPost method of the servlet. <br>
*
* This method is called when a form has its tag value method equals to post.
*
* @param request the request send by the client to the server
* @param response the response send by the server to the client
* @throws ServletException if an error occurred
* @throws IOException if an error occurred
*/
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException
{ response.setContentType("text/html");
PrintWriter out = response.getWriter();
out
.println("<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\">");
out.println("<HTML>");
out.println(" <HEAD><TITLE>A Servlet</TITLE></HEAD>");
out.println(" <BODY>");
out.print(" This is ");
out.print(this.getClass());
out.println(", using the POST method");
try
{ Context ctx = new InitialContext();
DataSource ds = (DataSource)ctx.lookup("java:comp/env/jdbc/mysql");
Connection conn = ds.getConnection();
ResultSet rs=conn.createStatement().executeQuery("select * from admininfo");
while(rs.next()){
out.print(rs.getString()); }
} catch (NamingException e) {
e.printStackTrace(out);
System.out.println(e.getMessage());
} catch (SQLException e) {
e.printStackTrace(out);
}
out.println("connection pool connected !!haha");
out.println(" </BODY>");
out.println("</HTML>");
out.flush();
out.close();
} /**
* Initialization of the servlet. <br>
*
* @throws ServletException if an error occurs
*/
public void init() throws ServletException
{
// Put your code here
} }
这里我的数据库名称:pos，我查询了admininfo表中的第二列的数据。
关键代码：
try
{ Context ctx = new InitialContext();
DataSource ds = (DataSource)ctx.lookup("java:comp/env/jdbc/mysql");
Connection conn = ds.getConnection();
ResultSet rs=conn.createStatement().executeQuery("select * from admininfo");
while(rs.next()){
out.print(rs.getString()); }
} catch (NamingException e) {
e.printStackTrace(out);
System.out.println(e.getMessage());
} catch (SQLException e) {
e.printStackTrace(out);
}
结果集rs，返回之后跟直接jdbc访问数据库差别不大了。
ps：其实我到没有感觉用数据库连接池有什么方便之处。但是学习的过程中，示例项目用到，就学习了一下。不然这个地方一直卡住。。。唉～还是太弱了。
参考：Myeclipse中的jdbc连接池配置
