Question

JSONObject获取值后为一个对象，将对象转为JSONObject时报错

从JSONObject中获取值，返回的是一个对象，再将这个对象转化为JSONObject时报错com.alibaba.fastjson.JSONException: expect ':' at 0, actual =

Answer 1

• 将json字符串转化成JavaBean对象

  Person person = new Person("1","gson",1);

  Gson gson = new Gson();

  //这里将javabean转化成json字符串

  String jsonString = gson.toJson(person);

  System.out.println(jsonString);

  //这里将json字符串转化成javabean对象,

  person = gson.fromJson(jsonString,Person.class);

• 将json字符串转化成List<JavaBean>对象

  Person person1 = new Person("1","gson1",1);

  Person person2 = new Person("2","gson2",2);

  List<Person> persons = new ArrayList<Person>();

  persons.add(person1);

  persons.add(person2);

  Gson gson = new Gson();

  //这里将lsit<javabean>转化成json字符串

  String jsonString = gson.toJson(persons);

  //解析json字符串

  List<Person> persons2 = gson.fromJson(jsonString, new TypeToken<List<Person>>(){}.getType());

• 将json字符串转化成List<String>对象

  List<String> list = new ArrayList<String>();

  list.add("gson1");

  list.add("gson2");

  list.add("gson3");

  Gson gson = new Gson();

  String jsonString = gson.toJson(list);

  System.out.println("json字符串:"+jsonString);

  //解析json字符串

  List<String> list2 = gson.fromJson(jsonString, new TypeToken<List<String>>(){}.getType());

• 将json字符串转化成List<Map<String,Object>>对象

  Map<String,Object> map = new HashMap<String,Object>();

  map.put("key1", "value1");

  map.put("key2", "value2");

  Map<String,Object> map2 = new HashMap<String,Object>();

  map2.put("key1", 1);

  map2.put("key2", 2);

  List<Map<String,Object>> list = new ArrayList<Map<String,Object>>();

  list.add(map);

  list.add(map2);

  Gson gson =  new Gson();

  String jsonString = gson.toJson(list);

  System.out.println("json字符串:"+jsonString);

  //解析json字符串

  List<Map<String,Object>> list2 = gson.fromJson(jsonString, new TypeToken<List<Map<String,Object>>>(){}.getType());