全局：
X:\jakarta-tomcat-5.0.28\conf\web.xml
<servlet>
<servlet-name>jsp</servlet-name>
<servlet-class>org.apache.jasper.servlet.JspServlet</servlet-class>
<init-param>
<param-name>fork</param-name>
<param-value>false</param-value>
</init-param>
<init-param>
<param-name>xpoweredBy</param-name>
<param-value>false</param-value>
</init-param>
下加入字段实现mysql的驱动调用：
<init-param>
<param-name>driver</param-name>
<param-value>com.mysql.jdbc.Driver</param-value>
</init-param>
<init-param>
<param-name>url</param-name>
<param-value>jdbc:mysql://192.168.0.13:3306/myweb</param-value>
</init-param>
<init-param>
<param-name>username</param-name>
<param-value>root</param-value>
</init-param>
<init-param>
<param-name>password</param-name>
<param-value>lovejack</param-value>
</init-param>
<load-on-startup>3</load-on-startup>
</servlet>
全局变量实现连接数据库的构造器：
public DbBean(ServletConfig config) {
try {
Class.forName(config.getInitParameter("driver"));
con = DriverManager.getConnection(
config.getInitParameter("url"),
config.getInitParameter("username"),
config.getInitParameter("password"));
}
catch (ClassNotFoundException e) {
e.printStackTrace();
}
catch (SQLException e) {
e.printStackTrace();
}
}
局部：
工程文件/WebRoot/WEB-INF/web.xml
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
后加字段：
<context-param>
<param-name>chairman</param-name>
<param-value>牛人</param-value>
</context-param>
<context-param>
<param-name>driver</param-name>
<param-value>com.mysql.jdbc.Driver</param-value>
</context-param>
<context-param>
<param-name>url</param-name>
<param-value>jdbc:mysql://192.168.0.13:3306/myweb</param-value>
</context-param>
<context-param>
<param-name>username</param-name>
<param-value>root</param-value>
</context-param>
<context-param>
<param-name>password</param-name>
<param-value>lovejack</param-value>
</context-param>
在网页中可以使用pageContext.getServletContext().getInitParameter("name")直接得到value
如：
<%@page pageEncoding="GBK" %>
<%
out.println(pageContext.getServletContext().getInitParameter("driver"));
out.println(pageContext.getServletContext().getInitParameter("url"));
out.println(pageContext.getServletContext().getInitParameter("username"));
out.println(pageContext.getServletContext().getInitParameter("password"));
out.println(pageContext.getServletContext().getInitParameter("chairman"));
%>