@Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
        Enumeration e = req.getParameterNames();
        while(e.hasMoreElements()){
            String paraName = (String) e.nextElement();
            //将得到的参数传入到 getParameterValues()方法中,返回的是一个字符型数组
            String[] paraValues = req.getParameterValues(paraName) ;
            if(paraValues.length == 1){
                String str = paraValues[0];
                System.out.println(str);
            }else{
                for(int i=0;i<paraValues.length;i++){
                    System.out.println(paraValues[i]);
                }
            }
        }
    }

　　@Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
        // 方法二 用getParameterMap ,map转换城set，map 没有 iterator 这个接口
        Map<String, String[]> map = req.getParameterMap();
        // 将map 转换城set Entry<key,value> 是map 中的一个接口可以通过 Map.Entry<key,value> 来调用
        Set<Map.Entry<String, String[]>> set = map.entrySet();
        for (Iterator<Map.Entry<String, String[]>> it = set.iterator(); it
                .hasNext();) {
            Map.Entry<String, String[]> entry = it.next();
            String paraName = entry.getKey();
            paraName = new String(paraName.getBytes("ISO8859-1"), "UTF-8");
            System.out.println(paraName);
            String[] paraValues = entry.getValue();
            if (paraValues.length == 1) {
                paraValues[0] = new String(paraValues[0].getBytes("iso8859-1"),
                        "utf-8");
                System.out.println(paraValues[0]);
            } else {
                for (int i = 0; i < paraValues.length; i++) {
                    paraValues[i] = new String(
                            paraValues[i].getBytes("iso8859-1"), "utf-8");
                    System.out.println(paraValues[i]);
                }
            }
        }

    }