json

經常使用json解析工具類

 

1.net.sf.json

               若是對象中包含對象 不能一次把json字符串 轉成對象，要一次一次轉

 

 

        User user = new User("bob",12); User user1 = new User(null,null); List<User> list = new ArrayList<>(); list.add(user1); list.add(user); System.out.println(JSONObject.fromObject(user1)); JSONArray jsonArray = JSONArray.fromObject(list); System.out.println(jsonArray.toString()); Map<String, String> map = new HashMap<>(); map.put("data", null); System.out.println(JSONObject.fromObject(map));

 輸出：

{"age":0,"name":""}
[{"age":0,"name":""},{"age":12,"name":"bob"}] {"data":null}

2.com.fasterxml.jackson

User user = new User("bob",12); User user1 = new User(null,null); List<User> list = new ArrayList<>(); list.add(user1); list.add(user); ObjectMapper objectMapper = new ObjectMapper(); try { JsonNode jsonNode = objectMapper.readTree(objectMapper.writeValueAsString(list)); System.out.println(jsonNode.toString()); Map<String, String> map = new HashMap<>(); map.put("data", null); System.out.println(objectMapper.writeValueAsString(map)); } catch (IOException e) { // TODO Auto-generated catch block  e.printStackTrace(); } }


3  FastJson

Student student = JSON.parseObject(JSON_OBJ_STR, new TypeReference<Student>() {});

ArrayList<Student> students = JSON.parseObject(JSON_ARRAY_STR, new TypeReference<ArrayList<Student>>() {});