Java-json相关转换，JSONObject与实体类/map互转、List/List＜map＞和JSONArray互转、获取JSONObject中的key value、字符串String转换等

博客背景是Java开发。json相关的转换、取值等在日常开发中经常使用，但有时候还是会忘记or遇到些奇奇怪怪的问题。以此记录，提醒自己～不定期更新～

1、JSONObject相关

实体类和JSONObject互转

//实体类转为JSONObjectJSONObject jsonObject = JSON.toJSON(entity);JSONObject jsonObject = JSONObject.parseObject(JSON.toJSONString(entity));//JSONObject转为实体类Entity entity = JSONObject.toJavaObject(jsonObject, Entity.class);

Map和JSONObject互转

//Map转为JSONObjectJSONObject jsonObject = JSON.toJSON(map);JSONObject jsonObject = JSONObject.parseObject(JSON.toJSONString(map));//JSONObject转为MapMap map = JSONObject.toJavaObject(jsonObject, Map.class);

String转JSONObject

JSONObject  jsonObject = JSONObject.fromObject(stringText);

实体类转JSON字符串时不过滤NULL空值

String jsonStr = JSONObject.toJSONString(VO,SerializerFeature.WriteMapNullValue);

获取JSONObject中的key value

JSONObject baseInfo = jsonObject.getJSONObject("detail");// 遍历基本信息for (Map.Entry entry : baseInfo.entrySet()) {    System.out.println(entry.getKey() + " : " + entry.getValue());}

2、JSONArray相关

List和JSONArray互转

//List转为JSONArrayJSONArray jsonArray = JSON.toJSON(list);JSONArray jsonArray = JSONArray.parseArray(JSON.toJSONString(list));//JSONArray转为ListList list = JSONObject.parseArray(jsonArray.toJSONString(), Entity.class);

List>和JSONArray互转

//List>转为JSONArrayJSONArray jsonArray = JSON.toJSON(maps);JSONArray jsonArray = JSONArray.parseArray(JSON.toJSONString(maps));//JSONArray转ListJSONArray array = jsonObject.getJSONArray("array");List objects = JSONObject.parseArray(JSONObject.toJSONString(array),HashMap.class);//JSONArray转为List>List> maps = JSONObject.parseArray(jsonArray.toJSONString(), Map.class);//JSONArray转为List>方法2List> list=new ArrayList>();               JSONArray jsonArr=JSONObject.fromObject(jsonStr).getJSONArray("data");if(jsonArr!=null && jsonArr.size()>0){for(int i=0;iJSONObject jsonObj=(JSONObject) jsonArr.get(i);Map map = new HashMap();for (Iterator iter = jsonObj.keys(); iter.hasNext(); ) {String key = (String) iter.next();String value = jsonObj.get(key).toString();map.put(key, value);}list.add(map);    }

JASONArray转为JSONObject

JSONArray result_type = new JSONArray();StringBuffer selectType = new StringBuffer();selectType.append(" select id from table");result_type = jdbcTemp.queryForJSONArray(selectType.toString());JSONObject jsonObject = new JSONObject();for (int i = 0; i < result_type.size(); i++) {    JSONObject jsonObject = (JSONObject) result_type.get(i);}return jsonObject;

解决问题：JASONArray转为JSONObject只返回了最后一个JSONObject

StringBuilder builder = new StringBuilder(); //业务代码//转换for (int i = 0; i < jsonArray.size(); i++) {    jsonObject = (JSONObject) jsonArray.get(i);    builder.append(jsonObject).append("\n"); } //业务代码return builder.toString();

String转JSONArray

JSONArray jsonArray = JSONArray.fromObject(stringText);

3、Object相关

Object转JSONObject

JSONObject json = (JSONObject) JSONObject.toJSON(list.get(0));

Object转List

//Object转Listpublic static List objToList1(Object obj) throw CoreException{List result = new ArrayList();    if (obj instanceof ArrayList) {        for (Object o : (List) obj) {            result.add(String.class.cast(o));        }        }        return result;}    //通用工具类  public static  List objToList(Object obj, Class cla) throw CoreException{List list = new ArrayList();    if (obj instanceof ArrayList) {        for (Object o : (List) obj) {            list.add(cla.cast(o));        }        return list;        }        return null;}    //调用 List list = objToList(obj,String.class);//注意：int.class = Integer.TYPE !=Integer.class

来源地址：https://blog.csdn.net/weixin_44436677/article/details/131269751