本例程所使用的运行环境及资源:
1. Tomcat 5.5
2. Mysql 4.1
3. mysql jdbc驱动:3.1.13
(以上程序可以直接到相关官方网站下载到)
step1:首先创建一个监听器servlet,这个监听器用来初始化共享资源,本例中主要用来在应用中创建数据源,把这个类置于WEB-INF/classes/kinglong/jmediasoft/servlets/目录下,代码如下:
/** */ /** * @(#)ResourceManagerListener.java * * 资源初始化监听器 * package kinglong.jmediasoft.servlets; import javax.servlet. * ; import javax.servlet.http. * ; import com.mysql.jdbc.jdbc2.optional. * ; public class ResourceManagerListener implements ServletContextListener { private DataSource ds = null ; public void contextInitialized(ServletContextEvent sce) { ServletContext application = sce.getServletContext(); String jdbcurl = application.getInitParameter( " jdbcURL " ); String user = application.getInitParameter( " user " ); String password = application.getInitParameter( " password " ); try { ds = new MysqlConnectionPoolDataSource(); ds.setUrl(jdbcurl); ds.setUser(user); ds.setPassword(password); } catch (Exception e) { application.log( " 无法创建数据源: " + e.getMessage()); return ; } application.setAttribute( " dataSource " ,ds);//将数据源变量置于应用作用域中 }
public void contextDestroyed(ServletContextEvent sce) { ServletContext application = sce.getServletContext(); application.removeAttribute( " dataSource " ); ds = null ; } }
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step2:配置web.xml相关代码,代码如下:
< context-param > < param-name > jdbcURL < param-value > jdbc:mysql://localhost:3306/comic < context-param > < param-name > user < param-value > root < context-param > < param-name > password < param-value > root < listener > < listener-class > kinglong.jmediasoft.servlets.ResourceManagerListener
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step3:建立测试页面,测试页面代码如下:
< sql:query var ="comicinfo" dataSource ="$ { dataSource}" sql ="SELECT * FROM comicinfo" /> < html > < head > < meta http-equiv ="Content-Type" content ="text/html; charset=gb2312" > < title > 数据库测试页面 < body > < table > < c:forEach items ="$ { comicinfo.rows}" var ="row" > < c:forEach items ="$ { row}" var ="column" > < tr > < td align ="right" >< b > $ { fn:escapeXml(column.key)}:
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< td align ="left" > $ { fn:escapeXml(column.value)}
step4:重新启动Tomcat应用,用http://localhost:8080/test/test.jsp的链接来执行此页面,我的输出如下。这是我的comicinfo表中的唯一一条记录。黑体是表的字段,后面是对应的字段值。
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