Web系统中web.xml的配置
1.Servlet配置
<servlet>
<servlet-name>login</servlet-name><!-- Servlet名称、用来匹配Servlet请求、若匹配上、则执行下边class的doPost或doGet方法 -->
<servlet-class>com.test.LoginServlet</servlet-class><!-- Servlet方法类、该类需要继承HttpServlet -->
</servlet>
<servlet-mapping>
<servlet-name>login</servlet-name><!-- Servlet名称、用来匹配<servlet>标签中的Servlet名称 -->
<url-pattern>/admin/login</url-pattern><!-- Servlet请求、例:http://localhost:8080/admin/login、则调用上边配置好的Servlet方法 -->
</servlet-mapping>
1.x Servlet类实现模板如下:
package gly.xiaowei.servlet; import java.io.IOException; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; public class LoginServlet extends HttpServlet { public void doPost(HttpServletRequest request, HttpServletResponse httpservletresponse) throws ServletException, IOException{ // 这里实现登陆的代码、或者在doGet方法中实现、 } public void doGet(HttpServletRequest request, HttpServletResponse httpservletresponse) throws ServletException, IOException{ } }
2.过滤器配置
注:web.xml中的过滤器需要实现Filter接口、
<filter>
<filter-name>setRequestEncoding</fiter-name><!-- 过滤器名称、用来匹配过滤器、若匹配上则调用下边类中的doFilter方法 -->
<filter-class>com.filter.SetRequestEncodingFilter</filter-class><!-- 过滤器方法类、该类需要实现Filter接口 -->
<init-param>
<param-name>encoding</param-name><!-- 过滤器的参数名称 -->
<param-value>UTF-8</param-value><!-- 过滤器的参数值 -->
<init-param>
<!-- 可以添加多个init-param标签 -->
<load-on-startup>1</load-on-startup>
<!--
1)load-on-startup元素标记容器是否在启动的时候就加载这个servlet(实例化并调用其init()方法)。
2)它的值必须是一个整数,表示servlet应该被载入的顺序
2)当值为0或者大于0时,表示容器在应用启动时就加载并初始化这个servlet;
3)当值小于0或者没有指定时,则表示容器在该servlet被选择时才会去加载。
4)正数的值越小,该servlet的优先级越高,应用启动时就越先加载。
5)当值相同时,容器就会自己选择顺序来加载。
-->
</fiter>
<filter-mapping>
<filter-name>setRequestEncoding</fiter-name>
<url-pattern>/*.do</url-pattern><!-- 所有以.do结尾的请求都会执行该过滤器 -->
</filter-mapping>
2.x过滤器类的实现模板如下:
package gly.xiaowei.base; import java.io.IOException; import javax.servlet.Filter; import javax.servlet.FilterChain; import javax.servlet.FilterConfig; import javax.servlet.ServletException; import javax.servlet.ServletRequest; import javax.servlet.ServletResponse; public class SetCharacterEncodingFilter implements Filter { protected String encoding = null; protected FilterConfig filterConfig = null; protected boolean ignore = true; public void destroy() { this.encoding = null; this.filterConfig = null; } // 每次请求符合要求时调用该过滤器方法... public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException { // Conditionally select and set the character encoding to be used request.getParameter(""); if (ignore || (request.getCharacterEncoding() == null)) { String encoding = selectEncoding(request); if (encoding != null) { request.setCharacterEncoding(encoding); } } // Pass control on to the next filter chain.doFilter(request, response); } // 容器启动时即服务器启动时执行该方法... public void init(FilterConfig filterConfig) throws ServletException { this.filterConfig = filterConfig; this.encoding = filterConfig.getInitParameter("encoding"); String value = filterConfig.getInitParameter("ignore"); if (value == null) this.ignore = true; else if (value.equalsIgnoreCase("true")) this.ignore = true; else if (value.equalsIgnoreCase("yes")) this.ignore = true; else this.ignore = false; } protected String selectEncoding(ServletRequest request) { return (this.encoding); } }
3.Session超时配置
3.1通过配置web.xml使session失效
<session-config> <session-timeout>120</session-timeout><!--单位:分钟、session120分钟后超时销毁--> </session-config>
3.2手动使session失效
public void invalidate();//使session失效方法。session.invalidate();
4.监听器的配置
<listener> <listener-class>com.listener.class</listener-class> </listener>
Listener配置信息必须在Filter和Servlet配置之前,Listener的初始化(ServletContentListener初始化)比Servlet和Filter都优先,而销毁比Servlet和Filter都慢