Servlet Request

• servlet请求域对象只在每次请求生效（http协议内容），两次请求时想要第二个servlet请求使用第一个请求域需要使用转发器

• RequestDispather dispather = request.getRequestDispather("/b");
  //Get dispather Object first
  dispather.forward(request,reponse);
  //use forward method in dispather sencondly
  + 注意到参数中传的是路径意味着所有资源都可以转发，至于路径从哪个根开始，还没搞清......
  
  + 关于request的两个方法  
  
    + ```java
      String usrname = request.getParameter("username");
      //uri?username=leo&paawd=123&sex=1
      Object obj = request.getAttribute("name");
      //After setAttribte
      
      //The first one is to get data from browser
      //the second one is to get request attribute data
  
  

• Request底层是Map集合，一个key一个value，Tomcat帮我们封装，相应的http协议内容以封装好

• 如何解决Post乱码问题

  • request.setCharacterEncoding("UTF-8");
    response.setContext("text/html;charset=utf-8");
    //this is the soultion for post method only
    + ```java
      request.setCharacterEncoding("UTF-8");
      response.setContext("text/html;charset=utf-8");
      //this is the soultion for post method only
    
    

• request其他常用方法

  • String method = request.getMethod();
    //Get http method
    + ```java
      String requestURI = request.getRequestURI();
      //Get request httpd  method (get/post)
    
    

  • String servletPath = request.getServletPath();
    //Get servlet Project Path
    

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