JAVA對象JSON數據互相轉換的四種常見情況

1. 把java 對象列表轉換為json對象數組，並轉為字符串

JSONArray array = JSONArray.fromObject(userlist);
    String jsonstr = array.toString();

 

2.把java對象轉換成json對象，並轉化為字符串

JSONObject object = JSONObject.fromObject(invite);
   String str=object.toString());

 

3.把JSON字符串轉換為JAVA 對象數組

String personstr = getRequest().getParameter("persons");
  JSONArray json = JSONArray.fromObject(personstr);
  List<InvoidPerson> persons = (List<InvoidPerson>)JSONArray.toCollection(json, nvoidPerson.class);

4.把JSON字符串轉換為JAVA 對象

 JSONObject jsonobject = JSONObject.fromObject(str);
  PassportLendsEntity passportlends = null;
  try {
   //獲取一個json數組
   JSONArray array = jsonobject.getJSONArray("passports");
   //將json數組 轉換成 List<PassPortForLendsEntity>泛型
   List<PassPortForLendsEntity> list = new ArrayList<PassPortForLendsEntity>();
   for (int i = 0; i < array.size(); i++) {   
            JSONObject object = (JSONObject)array.get(i);  
            PassPortForLendsEntity passport = (PassPortForLendsEntity)JSONObject.toBean(object,
              PassPortForLendsEntity.class);
            if(passport != null){
             list.add(passport);
            }  
     }
   //轉換PassportLendsEntity 實體類
  passportlends = (PassportLendsEntity)JSONObject.toBean(jsonobject, PassportLendsEntity.class);

 

  str = "{\"lendperson\":\"李四\",\"lendcompany\":\"有限公司\",\"checkperson\":\"李四\",

  \"lenddate\":\"2010-07-19T00:00:00\",\"lendcounts\":4,\"
  passports\":[{\"passportid\":\"d\",\"name\":\"李豫川\",\"passporttype\":\"K\"},
  {\"passportid\":\"K9051\",\"name\":\"李平\",\"passporttype\":\"K\"},
  {\"passportid\":\"K90517\",\"name\":\"袁寒梅\",\"passporttype\":\"K\"},
  {\"passportid\":\"K905199\",\"name\":\"賀明\",\"passporttype\":\"K\"}]}";