Java中Json的各种处理

一、net.sf.json

1、Json转Map

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

2、Json转实体

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

如果实体中带有List字段，需要指定泛型

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

3、Json转集合

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);
	}
}

另外一种：

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);
}

二、com.alibaba.fastjson

1、Json转Map

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

2、Json转实体

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

3、Json转集合

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