Json解析出错：MorphDynaBean cannot be cast to

左手的ㄟ右手 2022-09-18 04:57 53阅读 0赞

在json字符串转java bean时，一般的对象，可以直接转，如：一个学生类，属性有姓名、年龄等；

但是如果属性中含有复杂的类型，当其中属性有类似List , Map ,ArrayList、自定义的类型，如List<Teacher> teachers, 就不可以了。 会报错：MorphDynaBean cannot be cast to con.test……

在JSONObject.toBean的时候如果转换的类中有集合,可以先定义Map<String, Class> classMap = new HashMap<String, Class>();在classMap中put你要转换的类中的集合名,像:classMap.put("teachers", Teacher.class);然后在toBean()的时候把参数加上, 像:Student student=(Student) JSONObject.toBean(str, Student.class, classMap);

private RSPerfData getRSPerfDataFromJSON(String jsonString) throws Exception{
    		HashMap<String, Class> classMap = new HashMap<String, Class>(); 
    		classMap.put("empDataData", RSEmpData.class);
            JSONObject jsonObject = JSONObject.fromObject(jsonString);
            WBQEncode_Decoder.my_decode_v2(jsonObject);
            RSPerfData rsPerfData = (RSPerfData) JSONObject.toBean(jsonObject, RSPerfData.class, classMap);
    		return rsPerfData;
    	}

public class WBQEncode_Decoder
    {
    
        public static void my_decode_v2(Object object) throws Exception
        {
        	if (object instanceof JSONObject)
            {// 是對象
                JSONObject jsonObject = (JSONObject) object;
                handleJsonObject(jsonObject);
            } else if (object instanceof JSONArray)
            {// 是對象
                JSONArray jsonArray = (JSONArray) object;
                int length = jsonArray.size();
                for (int i = 0; i < length; i++)
                {
                    JSONObject jsonObject = (JSONObject) jsonArray.get(i);
                    handleJsonObject(jsonObject);
                    jsonArray.set(i, jsonObject);
                }
            }
        }
    
        public static void my_encode_v2(List<Map<String, Object>> list) throws IOException
        {
            if (list == null || list.isEmpty())
            {
                return;
            }
            for (Iterator<Map<String, Object>> iterator = list.iterator(); iterator.hasNext();)
            {
                Map<String, Object> map = iterator.next();
                Set<String> keys = map.keySet();
                for (Iterator<String> iterator2 = keys.iterator(); iterator2.hasNext();)
                {
                    String key = iterator2.next();
                    Object object = map.get(key);
                    if (object == null || object instanceof String || object instanceof Number)
                    {
                        if (object == null)
                        {
                            object = "";
                        }
                        String value = object.toString();
                        if (value.equals("null") || value.equals("undefined"))
                        {
                            value = "";
                        }
                        value = URLEncoder.encode(value, "utf-8");
                        value = value.replaceAll("\\+", "百分之20(直接寫的話博客上看不到)");// 其實+號是URLEncoder.encode後把空格轉成+了，在頁面上解碼的時候是把空格當作了，所以要把+替換成
    
                        map.put(key, value);
                    }
                }
            }
        }
    
        @SuppressWarnings("unchecked")
        private static void handleJsonObject(JSONObject jsonObject) throws Exception
        {
            Set<String> keys = jsonObject.keySet();
            for (Iterator<String> iterator = keys.iterator(); iterator.hasNext();)
            {
                String key = iterator.next();
                String objectStr = jsonObject.get(key).toString();
                if ((objectStr.startsWith("{") && objectStr.endsWith("}")))
                {
                    my_decode_v2(JSONObject.fromObject(objectStr));
                } else if (objectStr.startsWith("[") && objectStr.endsWith("]"))
                {
                    JSONArray jay = JSONArray.fromObject(objectStr);
                    my_decode_v2(jay);
                    jsonObject.put(key, jay);
                } else
                {
                    objectStr = URLDecoder.decode(objectStr, "utf-8");
                    if (objectStr.equals("null") || objectStr.equals("undefined"))
                    {
                        objectStr = "";
                    }
                    
                    objectStr = URLDecoder.decode(objectStr ,"utf-8");
                    
                    jsonObject.put(key, objectStr);
                }
            }
        }
    }

\[ERROR\]java.lang.NoSuchMethodException .<init>()

有可能是你的转换的class非public。