获取HttpServletRequest，将参数解析成Map

1、将URL中参数转换成Map，如客户端发送http://localhost/login?name=aa&age=21&address=bbb，用grequest.getQueryString()方法得到name=aa&age=21&address=bbb，然后再分割，注：request.getQueryString()方法只对GET请求有效。

    public static Map<String, String> getUrlQueryMap(HttpServletRequest request) {
        String urlQueryString = request.getQueryString();
        Map<String, String> queryMap = new HashMap<>();
        String[] arrSplit;
        if (urlQueryString == null) {
            return queryMap;
        } else {
            //每个键值为一组
            arrSplit = urlQueryString.split("[&]");
            for (String strSplit : arrSplit) {
                String[] arrSplitEqual = strSplit.split("[=]");
                //解析出键值
                if (arrSplitEqual.length > 1) {
                    queryMap.put(arrSplitEqual[0], arrSplitEqual[1]);
                } else {
                    if (!"".equals(arrSplitEqual[0])) {
                        queryMap.put(arrSplitEqual[0], "");
                    }
                }
            }
        }
        return queryMap;
    }

2、在POST请求中，且Content-type为Form请求时，将Body中的参数转换成Map，注：此方法可以获取URL中参数，非Form文本类型时，将获取不到参数（更request.getParameterNames()方法有关）。

    public static Map<String, String> getQueryMap(HttpServletRequest request) {
        Enumeration enumeration = request.getParameterNames();
        Map<String, String> queryMap = new HashMap<>();
        while (enumeration.hasMoreElements()) {
            String paramName = (String) enumeration.nextElement();
            String[] values = request.getParameterValues(paramName);
            if (values.length != 0) {
                queryMap.put(paramName, values[0]);
            } else {
                queryMap.put(paramName, "");
            }
        }
        return queryMap;
    }