JavaWeb修改请求参数信息

我就是我 2023-02-11 11:28 21阅读 0赞

客户端发送请求：http://localhost:8080/test/xxx.action?name="palading"&age=24
    
            HttpServlet类中调用：
    
            Map<String, String[]>map=request.getParameterMap();
            for(String key:map.keySet()){
            if(key.equals("name")){
            map.put("name",new String[]{"小明"});
            }
            }
    
            HttpServlet引发异常
            java.lang.IllegalStateException:No modifications are allowed to a locked ParameterMap
    
            默认情况下只能查看请求参数信息，不能修改参数信息。
            所以继承要HttpServletRequestWrapper重写getParameter方法：
    
    public class MyHttpServletWrapp extends HttpServletRequestWrapper {
        HttpServletRequest request;
    
        public MyHttpServletWrapp(HttpServletRequest request) {
            super(request);
            this.request = request;
        }
    
        @Override
        public String getParameter(String name) {
            if ("name".equals(name))
                return "Test";
            return super.getParameter(name);
        }
    
    }
    
    
    新建过滤器类 implements Filter
    public void doFilter(ServletRequest request,ServletResponse response,FilterChain chain)throws IOException,ServletException{
            MyHttpServletWrapp myHttpServletWrapp=new MyHttpServletWrapp((HttpServletRequest)request);
    
            重新包装发送请求
            chain.doFilter(myHttpServletWrapp,response);
            }
    
            在HttpServlet中获取请求参数信息 发现请求参数信息已经被改变
    protected void doGet(HttpServletRequest request,HttpServletResponse response)throws ServletException,IOException{
    
            String name=request.getParameter("name");
            System.out.println(name);
    
            }