Request

 <form action="/day9/servlet/requestDemo2" method="post">
    　用户名：<input type="text" name="username"/><br/>
 　　 密码：<input type="password" name="password"><br/>
 　　 性别:<input type="radio" name="gender" value="male">男
 　　　　 <input type="radio" name="gender" value="female">女<br/>
　　　所在地：<select name="location">
             <option value="shanghai">上海</option>
             <option value="henan">河南</option>
             <option value="beijing">北京</option>
         </select><br/>
 　　爱好：<input type="checkbox" name="likes" value="sing">唱歌
　　 <input type="checkbox" name="likes" value="tiaowu">跳舞
 　　<input type="checkbox" name="likes" value="paobu">跑步
 　　<input type="checkbox" name="likes" value="dushu">读书<br/>
　　 备注：<textarea row="3" row="60" name="description" ></textarea><br/>
　　大头贴：<input type="file" name="imapge" ><br/>
　　<input type="hidden" name="id" value="890">
　　<input type="submit" value="提交">
</form>

    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        System.out.println(request.getParameter("username"));
        System.out.println(request.getParameter("password"));
        System.out.println(request.getParameter("gender"));
        System.out.println(request.getParameter("location"));
        String    likes[]=request.getParameterValues("likes");
        for(int i=0;likes!=null&&i<likes.length;i++){
            System.out.println(likes[i]);
        }
        System.out.println(request.getParameter("description"));
        System.out.println(request.getParameter("id"));
        
    }

    //get 方式乱发解决问题
    private void test1(HttpServletRequest request) throws UnsupportedEncodingException{
        String username=request.getParameter("username");
        username=new String(username.getBytes("iso8859-1"),"UTF-8");
        System.out.println(username);
    }
    //post 方式乱码解决问题
    private void test2(HttpServletRequest request) throws UnsupportedEncodingException{
        request.setCharacterEncoding("UTF-8");
        String username=request.getParameter("username");
        System.out.println(username);
    }

    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        String data="aaa";
        request.setAttribute("data", data);
        request.getRequestDispatcher("/test.jsp").forward(request, response);
    
    }

    String data = "rsl";  
    PrintWriter writer = response.getWriter();  
    writer.write(data);  
    writer.close();  
    request.getRequestDispatcher("/index.jsp").forward(request, response);  

        String data = "rsl";
        if(true){
            request.getRequestDispatcher("/index.jsp").forward(request, response);
            return ；//解决只要加个return就可以
        }
        request.getRequestDispatcher("/index.jsp").forward(request, response);
        

String data = "rsl";  
PrintWriter writer = response.getWriter();  
writer.write(data);  
request.getRequestDispatcher("/index.jsp").forward(request, response);