本页的热门答案使用了太简单的例子，比如只有一个属性的对象(例如{name: value})。我认为这个简单但真实的例子可以帮助到一些人。

这是谷歌Translate API返回的JSON:

{
  "data": 
     {
        "translations": 
          [
            {
              "translatedText": "Arbeit"
             }
          ]
     }
}

我想检索“translatedText”属性的值。“Arbeit”使用谷歌的Gson。

两种可能的方法:

Retrieve just one needed attribute String json = callToTranslateApi("work", "de"); JsonObject jsonObject = new JsonParser().parse(json).getAsJsonObject(); return jsonObject.get("data").getAsJsonObject() .get("translations").getAsJsonArray() .get(0).getAsJsonObject() .get("translatedText").getAsString(); Create Java object from JSON class ApiResponse { Data data; class Data { Translation[] translations; class Translation { String translatedText; } } } ... Gson g = new Gson(); String json =callToTranslateApi("work", "de"); ApiResponse response = g.fromJson(json, ApiResponse.class); return response.data.translations[0].translatedText;

几乎所有给出的答案都要求在访问感兴趣的属性中的值之前，将JSON完全反序列化为Java对象。另一种不走这条路的替代方法是使用JsonPATH，它类似于JSON的XPath，允许遍历JSON对象。

它是一个规范，JayWay的优秀人员已经为该规范创建了一个Java实现，您可以在这里找到:https://github.com/jayway/JsonPath

所以基本上要使用它，把它添加到你的项目中，例如:

<dependency>
    <groupId>com.jayway.jsonpath</groupId>
    <artifactId>json-path</artifactId>
    <version>${version}</version>
</dependency>

并使用:

String pageName = JsonPath.read(yourJsonString, "$.pageInfo.pageName");
String pagePic = JsonPath.read(yourJsonString, "$.pageInfo.pagePic");
String post_id = JsonPath.read(yourJsonString, "$.pagePosts[0].post_id");

等等……

查看JsonPath规范页面，了解横向JSON的其他方法的更多信息。

您可以使用Gson库来解析JSON字符串。

Gson gson = new Gson();
JsonObject jsonObject = gson.fromJson(jsonAsString, JsonObject.class);

String pageName = jsonObject.getAsJsonObject("pageInfo").get("pageName").getAsString();
String pagePic = jsonObject.getAsJsonObject("pageInfo").get("pagePic").getAsString();
String postId = jsonObject.getAsJsonArray("posts").get(0).getAsJsonObject().get("post_id").getAsString();

你也可以循环"posts"数组，如下所示:

JsonArray posts = jsonObject.getAsJsonArray("posts");
for (JsonElement post : posts) {
  String postId = post.getAsJsonObject().get("post_id").getAsString();
  //do something
}

{
   "pageInfo": {
         "pageName": "abc",
         "pagePic": "http://example.com/content.jpg"
    },
    "posts": [
         {
              "post_id": "123456789012_123456789012",
              "actor_id": "1234567890",
              "picOfPersonWhoPosted": "http://example.com/photo.jpg",
              "nameOfPersonWhoPosted": "Jane Doe",
              "message": "Sounds cool. Can't wait to see it!",
              "likesCount": "2",
              "comments": [],
              "timeOfPost": "1234567890"
         }
    ]
}

Java code :

JSONObject obj = new JSONObject(responsejsonobj);
String pageName = obj.getJSONObject("pageInfo").getString("pageName");

JSONArray arr = obj.getJSONArray("posts");
for (int i = 0; i < arr.length(); i++)
{
    String post_id = arr.getJSONObject(i).getString("post_id");
    ......etc
}

Gson很容易学习和实现，我们需要知道的是以下两种方法

toJson() -将Java对象转换为JSON格式 fromJson() -将JSON转换为Java对象

`

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import com.google.gson.Gson;

public class GsonExample {
    public static void main(String[] args) {

    Gson gson = new Gson();

    try {

        BufferedReader br = new BufferedReader(
            new FileReader("c:\\file.json"));

        //convert the json string back to object
        DataObject obj = gson.fromJson(br, DataObject.class);

        System.out.println(obj);

    } catch (IOException e) {
        e.printStackTrace();
    }

    }
}

`

The below example shows how to read the text in the question, represented as the "jsonText" variable. This solution uses the Java EE7 javax.json API (which is mentioned in some of the other answers). The reason I've added it as a separate answer is that the following code shows how to actually access some of the values shown in the question. An implementation of the javax.json API would be required to make this code run. The full package for each of the classes required was included as I didn't want to declare "import" statements.

javax.json.JsonReader jr = 
    javax.json.Json.createReader(new StringReader(jsonText));
javax.json.JsonObject jo = jr.readObject();

//Read the page info.
javax.json.JsonObject pageInfo = jo.getJsonObject("pageInfo");
System.out.println(pageInfo.getString("pageName"));

//Read the posts.
javax.json.JsonArray posts = jo.getJsonArray("posts");
//Read the first post.
javax.json.JsonObject post = posts.getJsonObject(0);
//Read the post_id field.
String postId = post.getString("post_id");

现在，在大家对这个答案投反对票之前因为它没有使用GSON, org。json, Jackson或任何其他可用的第三方框架，它是每个问题解析所提供文本的“所需代码”的示例。我很清楚JDK 9没有考虑遵守当前标准JSR 353，因此JSR 353规范应该与任何其他第三方JSON处理实现一样对待。