web.xml配置详解

常用配置

　　修改web应用默认首页

  <welcome-file-list>
    <welcome-file>index.html</welcome-file>//写首页的名称就行了
  </welcome-file-list>

　　Servlet通配符映射及初始化参数

　　

  <servlet>
      <servlet-name>patternServlet</servlet-name>
      <servlet-class>com.imooc.pattern.Employer</servlet-class>
  </servlet>
  <servlet-mapping>
      <servlet-name>patternServlet</servlet-name>
      <url-pattern>/employer/*</url-pattern>
  </servlet-mapping>

    String url = request.getRequestURI();
        System.out.println(url);    
        
        String employerId = url.substring(url.lastIndexOf("/")+1);
        
        System.out.println(employerId);
        
        if(employerId.equals("1")) {
            response.getWriter().println("wuyi");
        }

　

　　全局配置

　　　　

  <context-param>
      <param-name>content</param-name>
      <param-value>© 2020 imooc.com  京ICP备 12003892号-11</param-value>
  </context-param>

ServletContext context    = request.getServletContext();
        
        String content = context.getInitParameter("content");
        
        context.setAttribute("content", content);
        context.setAttribute("title", "<h1>幕课网</h1>");
        
        response.setContentType("text/html;charset=utf-8");
        
        response.getWriter().println("ServletContext 学习");

　　　　　

　设置 404、500等状态码默认页面

　　

  <!-- 指定错误页面 -->
  <error-page>
      <error-code>404</error-code>
      <location>/error/404.html</location>
  </error-page>