servlet简单小记

1.servlet主要就是服务器端的CGI程序 采用线程 CGI选用的是进程
2.格式:
☆package %packagepath%
☆import java.io.*;
  import javax.servlet.*;
  import javax.servlet.http.*;
☆public class %name% extends HttpServlet
{
      public void init()throws ServletException
      {}
      //public void init(ServletConfig conf)throws ServletException{}
      public void doGet(HttpServletRequest rsq,HttpServletResponse res)throws IOException,ServletException{}
      public void doGet(HttpServletRequest rsq,HttpServletResponse res)throws IOException,ServletException
      {
           this.doGet(rsq,res);
      }
      public void destroy(){}
}
3.修改web.xml
<servlet>
<servlet-name>%servletname%</servlet-name>
<servlet-class>%package%</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>%servletname%</servlet-name>
<url-pattern>在浏览器中输入的地址</url-pattern>
</servlet-mapping>
只要是修改web.xml必须重启服务器
4.多个名称映射同意servlet
☆只需增加
<servlet-mapping>
<servlet-name>%servletname%</servlet-name>
<url-pattern>在浏览器中输入的地址</url-pattern>
</servlet-mapping>
就可以了 只要映射名称为"*",就可以任意匹配
5.解决路径问题:
实际的HTML或者JSP在/servlet/xxx.html
在web.xml中拼凑出路径
<servlet-mapping>
<servlet-name>%servletname%</servlet-name>
<url-pattern>/servlet/xxx</url-pattern>
</servlet-mapping>
表单中的action="xxx"
6.servlet中
HttpSession session=req.getSession();通过request对象取得
☆ServletContext app=this.getServletContext();  public void init()无参数
☆ServletContext app=this.conf.getServletContext();
  private ServletConfig conf=null;
  public void init(ServletConfig conf)throws ServletException
{
    this.conf=conf;
}
 看见servlet必须想到web.xml