What are the processing methods of Json in Java?

Various processing of Java Json

1. net.sf.json

1. Json to Map

JSONObject jsonObject = JSONObject.fromObject(jsonStr);
Map map = new HashMap<>();
map.put("code",jsonObject .getInt("code"));

2. Convert Json to entity

JSONObject jsonObject = JSONObject.fromObject(jsonStr);
ArticleForm articleForm = (ArticleForm) JSONObject.toBean(jsonObject , ArticleForm.class);

If the entity has a List field, you need to specify the generic type

Map classMap = new HashMap();
classMap.put("keywords", String.class);
ArticleForm articleForm = (ArticleForm) JSONObject.toBean(data.getJSONObject(i), ArticleForm.class,classMap);

3. Convert Json to collection

List list = new ArrayList<>();
JSONArray data = jsonObject.getJSONArray("data");
if (errorCode == 0 && data != null && !data.isEmpty()) {
    for (int i = 0; i < data.size(); i++) {
        Map classMap = new HashMap();
        classMap.put("keywords", String.class);
        ArticleForm articleForm = (ArticleForm) JSONObject.toBean(data.getJSONObject(i), ArticleForm.class,classMap);
        list.add(articleForm);
    }
}

Another one:

List list = new ArrayList<>();
JSONArray data = jsonObject.getJSONArray("data");
if (errorCode == 0 && data != null && !data.isEmpty()) {
    Map classMap = new HashMap();
    classMap.put("keywords", String.class);
    list  = (List) JSONArray.toArray(data, ArticleForm.class,classMap);
}

2. com.alibaba.fastjson

1. Convert Json to Map

JSONObject jsonObject = JSON.parseObject(jsonStr);
Map map = new HashMap<>();
map.put("code",jsonObject .getInt("code"));

2. Convert Json to entity

ArticleForm articleForm = JSON.parseObject(jsonStr, new TypeReference() {});

3. Convert Json to collection

List list = JSON.parseObject(jsonStr,new TypeReference>() {});

Java commonly used json processing

// String和json的互相转换
        String str = "{\"status\":200,\"message\":\"\",\"data\":{\"KmList\":[\"总分\",\"语文\",\"数学\",\"英语\",\"道德与法治\",\"科学基础\"]}}";
        System.out.println("str:"+str);
//        JSONArray arrays = JSON.parseArray(str);        // string转jsonArray
        JSONObject jsonObject = JSON.parseObject(str);    // string转jsonObject
        System.out.println("jsonObject:"+jsonObject);
        String s = jsonObject.toJSONString();             // json（object和Array相同）转string
  
        // json转list