java.lang.IllegalStateException: No modifications are allowed to a locked ParameterMap

java.lang.IllegalStateException: No modifications are allowed to a locked ParameterMap

在拦截器中，拦截请求参数，对参数进行处理，避免跨域注入漏洞等问题；

将request中的参数 进行替换时出现的错误
 Map<String, String[]> params =  request.getParameterMap();
if (params.size() > 0) {
	for (String key : params.keySet()) {
		String[] vlaue = params.get(key);
		vlaue[0] = HTMLEncode(vlaue[0]);
		params.put(key,vlaue);
	}
}

修改如下：
Map<String, String[]> params = new HashMap(request.getParameterMap());
	if (params.size() > 0) {
		for (String key : params.keySet()) {
			String[] vlaue = params.get(key);
			vlaue[0] = HTMLEncode(vlaue[0]);
			params.put(key,vlaue);
		}
	}

	public static String HTMLEncode(String aText){
        final StringBuilder result = new StringBuilder();
        final StringCharacterIterator iterator = new StringCharacterIterator(aText);
        char character =  iterator.current();
        while (character != CharacterIterator.DONE ){
            if (character == '<') {
                result.append("<");
            }
            else if (character == '>') {
                result.append(">");
            }
            else if (character == '&') {
                result.append("&");
            }
            else if (character == '\"') {
                result.append(""");
            }
            else {
                result.append(character);
            }
            character = iterator.next();
        }
        return result.toString();
    }

总结：在java中,对象直接进行等于操作的时候会关联原对象 原对象不可以进行修改 新参数也无法进行修改