request.getParameter("username")为null

Question

​
servlet代码
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("UTF-8");
BufferedReader br=request.getReader();
String line=null;
while((line=br.readLine())!=null) {
System.out.println(line);
response.getWriter().write("hello");
}

    String use=request.getParameter("username");
    System.out.println(use);
}

 html代码

<input name="username" type="text" /> <input type="submit" />

控制台输出结果
username=%E5%BC%A0%E4%B8%89
null

 

 我输入的是”张三“，上面一个乱码，下面一个直接为空，求解决一下

​

Answer 1

String username = new String(request.getParameter("username").getBytes("iso-8859-1"), "utf-8");