在Android中解析嵌套的JSON对象

Question

我正在尝试解析一个 JSON 对象，其中一部分如下所示：

{
"offer":{
    "category":"Salon",
    "description":"Use this offer now to enjoy this great Salon at a 20% discount. ",
    "discount":"20",
    "expiration":"2011-04-08T02:30:00Z",
    "published":"2011-04-07T12:00:33Z",
    "rescinded_at":null,
    "title":"20% off at Jun Hair Salon",
    "valid_from":"2011-04-07T12:00:31Z",
    "valid_to":"2011-04-08T02:00:00Z",
    "id":"JUN_HAIR_1302177631",
    "business":{
        "name":"Jun Hair Salon",
        "phone":"2126192989",
        "address":{
            "address_1":"12 Mott St",
            "address_2":null,
            "city":"New York",
            "cross_streets":"Chatham Sq & Worth St",
            "state":"NY",
            "zip":"10013"
        }
    },

等等......

到目前为止，我可以通过做这种事情来非常简单地解析：

JSONObject jObject = new JSONObject(content);
JSONObject offerObject = jObject.getJSONObject("offer");
String attributeId = offerObject.getString("category");
System.out.println(attributeId);

String attributeValue = offerObject.getString("description");
System.out.println(attributeValue);

String titleValue = offerObject.getString("title");
System.out.println(titleValue);`

但是当我尝试使用“name”时:' 这不会起作用。

我尝试过：

JSONObject businessObject = jObject.getJSONObject("business");
String nameValue = businesObject.getString("name");
System.out.println(nameValue);

当我尝试这样做时，我得到“JSONObject [business] not found”。

当我尝试时：

String nameValue = offerObject.getString("name");
System.out.println(nameValue);`

正如预期的那样，我得到“未找到 JSONObject [name]”。

我在这里做错了什么？我缺少一些基本的东西......

Answer 1

好吧，我是个白痴。这有效。

JSONObject businessObject = offerObject.getJSONObject("business");
String nameValue = businessObject.getString("name");
System.out.println(nameValue);

如果我在发帖前想两秒钟就好了……天啊！

Answer 2

这是单行解决方案

String myString = myJsonObject.getJSONObject("offer").getJSONObject("business").getString("name");

Answer 3

请注意，与 Java 对象之间的 JSON 序列化/反序列化不必“手动”完成。 GSON 和 Jackson 使这变得非常容易。

import java.text.DateFormat;
import java.util.Date;
import com.google.gson.FieldNamingPolicy;
import com.google.gson.Gson;
import com.google.gson.GsonBuilder;


公共课 Foo
{
  静态字符串 jsonInput = 
    “{”+ 
      "\"报价\":{" + 
        "\"类别\":\"沙龙\"," + 
        "\"description\":\"立即使用此优惠，以 20% 的折扣享受这个精彩的沙龙。 \"," + 
        "\"折扣\":\"20\"," + 
        "\"过期\":\"2011-04-08T02:30:00Z\"," + 
        "\"发布\":\"2011-04-07T12:00:33Z\"," + 
        "\"recinded_at\":null," + 
        "\"title\":\"Jun Hair Salon 20% 折扣\"," + 
        "\"valid_from\":\"2011-04-07T12:00:31Z\"," + 
        "\"valid_to\":\"2011-04-08T02:00:00Z\"," + 
        "\"id\":\"JUN_HAIR_1302177631\"," + 
        "\"业务\":{" + 
          "\"名称\":\"Jun美发沙龙\"," + 
          "\"电话\":\"2126192989\"," + 
          "\"地址\":{" + 
            "\"address_1\":\"莫特街 12 号\"," + 
            "\"address_2\":null," + 
            "\"城市\":\"纽约\"," + 
            "\"cross_streets\":\"查塔姆广场和值得圣\"," + 
            "\"州\":\"NY\"," + 
            "\"zip\":\"10013\"" + 
          “}”+ 
        “}”+ 
      “}”+ 
    “}”；

 public static void main(String[] args) 抛出异常
  {
    GsonBuilder gsonBuilder = new GsonBuilder();
    // gsonBuilder.setFieldNamingPolicy(FieldNamingPolicy.LOWER_CASE_WITH_UNDERSCORES);
    gsonBuilder.setDateFormat(DateFormat.LONG);
    Gson gson = gsonBuilder.create();
    OfferContainer OfferContainer = gson.fromJson(jsonInput, OfferContainer.class);
    System.out.println(offerContainer);
  }
 类

OfferContainer 
{
  私募报价；

 @覆盖
  公共字符串 toString()
  {
    返回offer.toString();
  }
}

类优惠
{
  私人类别类别；
  私有字符串描述；
  私人字符串折扣；
  私人日期到期；
  私人发布日期；
  私有字符串recinded_at；
  私有字符串标题；
  私人日期 valid_from；
  私有日期 valid_to；
  私有字符串 ID；
  私营企业；

 @覆盖
  公共字符串 toString()
  {
    返回字符串.format(
            “[优惠：类别=%1$s，描述=%2$s，折扣=%3$s，到期=%4$s，已发布=%5$s，recinded_at=%6$s，标题=%7 $s，valid_from=%8$s，valid_to=%9$s，id=%10$s，业务=%11$s]"，
            类别、描述、折扣、过期、已发布、recinded_at、标题、valid_from、valid_to、id、
            商业）;
  }
}

枚举类别
{
  沙龙
}

商务舱
{
  私有字符串名称；
  私人字符串电话；
  私人地址地址；

 @覆盖
  公共字符串 toString()
  {
    返回字符串.format(
        "[公司：姓名=%1$s，电话=%2$s，地址=%3$s]",
        姓名、电话、地址）；
  }
}

类地址
{
  私有字符串地址_1；
  私有字符串地址_2；
  私人字符串城市；
  私有字符串cross_streets；
  私有字符串状态；
  私有字符串 zip；

 <代码>@Override
  公共字符串 toString()
  {
    返回字符串.format(
        "[地址：address_1=%1$s、address_2=%2$s、城市=%3$s、cross_streets=%4$s、州=%5$s、zip=%6$s]",
        地址_1、地址_2、城市、cross_streets、州、邮政编码）；
  }
}

Note that a FieldNamingPolicy can be used to easily map attribute names from the JSON to the Java code. The LOWER_CASE_WITH_UNDERSCORES policy unfortunately does not work with JSON attribute names like "address_1".

如果您关心 JSON 处理的性能，请查看 Jackson Vs. Gson 和 http://www.cowtowncoder.com/博客/archives/2011/01/entry_437.html