request.getParameterMap值[Ljava.lang.String; cannot be cast to java.lang.String错误
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今天使用request.getParameterMap()获得Map中的数据时,使用
Map map=hrequest.getParameterMap();
Set key = map.keySet();
for(Object aaa: key.toArray()){
parakey = aaa.toString();
paravalue = (String)map.get(aaa);
requestpath = requestpath+"?"+parakey+"="+paravalue;
}
Map map=hrequest.getParameterMap();
Set key = map.keySet();
for(Object aaa: key.toArray()){
parakey = aaa.toString();
paravalue = (String)map.get(aaa);
requestpath = requestpath+"?"+parakey+"="+paravalue;
}
报[Ljava.lang.String; cannot be cast to java.lang.String错误,上网查了才知道get(key)返回的是String[],所以要使用字符串数组转换读取,参见英文接口文档:
所以可以创建工具类转化为普通map:
/** * 从request中获得参数Map,并返回可读的Map * * @param request * @return */@SuppressWarnings("unchecked")public static Map getParameterMap(HttpServletRequest request) { // 参数Map Map properties = request.getParameterMap(); // 返回值Map Map returnMap = new HashMap(); Iterator entries = properties.entrySet().iterator(); Map.Entry entry; String name = ""; String value = ""; while (entries.hasNext()) { entry = (Map.Entry) entries.next(); name = (String) entry.getKey(); Object valueObj = entry.getValue(); if(null == valueObj){ value = ""; }else if(valueObj instanceof String[]){ String[] values = (String[])valueObj; for(int i=0;i<values.length;i++){ value = values[i] + ","; } value = value.substring(0, value.length()-1); }else{ value = valueObj.toString(); } returnMap.put(name, value); } return returnMap;}
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