java - 如何在java中没有任何JSONArray的情况下解析JSON？答案

【问题标题】：How to parse JSON without having any JSONArray in java?java - 如何在java中没有任何JSONArray的情况下解析JSON？
【发布时间】：2016-07-27 19:51:27
【问题描述】：

我有一个像这样的 json 文件：

{
  "a1" : {
    "Contestant 1 marks" : 44,
    "Contestant 10 marks" : 30,
    "Contestant 11 marks" : 15,
    "Contestant 12 marks" : 35,
    "Contestant 13 marks" : 28,
    "Contestant 14 marks" : 8,
    "Contestant 2 marks" : 35,
    "Contestant 3 marks" : 30.899999618530273,
    "Contestant 4 marks" : 39,
    "Contestant 5 marks" : 45,
    "Contestant 6 marks" : 47,
    "Contestant 7 marks" : 17,
    "Contestant 8 marks" : 37,
    "Contestant 9 marks" : 35
  },
  "a2" : {
    "Contestant 1 marks" : 35,
    "Contestant 10 marks" : 30,
    "Contestant 11 marks" : 15,
    "Contestant 12 marks" : 35,
    "Contestant 13 marks" : 28,
    "Contestant 14 marks" : 8,
    "Contestant 2 marks" : 30,
    "Contestant 3 marks" : 30.899999618530273,
    "Contestant 4 marks" : 39,
    "Contestant 5 marks" : 45,
    "Contestant 6 marks" : 47,
    "Contestant 7 marks" : 17,
    "Contestant 8 marks" : 37,
    "Contestant 9 marks" : 35
  }
}

这里好像有两个 JSON 对象 a1，a2。而这些对象本身就有 14 个 JSON 对象。

我有一个 String completeJson;，其中包含完整的 JSON。

现在我写的时候

JSONObject jsonRootObj = new JSONObject(completeJson);

那么json对象会进入jsonRootObj呢？

另外，我如何在我的 JSON 文件中获取密钥的值：a1 和 a2 的“参赛者 1 分数”？

我想将a1 中的对象的值与a2 中具有相同KEY 的对象的值相加。

【问题讨论】：

jsonRootObj.get("a1").get("Contestant 1 scores") 因为您发布的json不包含任何数组
对不起，你需要投：((JSONObject)jo.get("a1")).get("参赛者1分")

标签： java json

【解决方案1】：

这样你就可以从 A1 中获取值了：

long valA1 = ((Long)((JSONObject)jo.get("a1")).get("Contestant 1 marks")).longValue();

这样你把A2放进去：

((JSONObject)((JSONObject)jo.get("a2")).get("Contestant 1 marks")).put("Contestant 1 marks", valA1);

jo 在哪里：

JSONParser jp = new JSONParser();
JSONObject jo = (JSONObject)jp.parse(<your json string>);

【讨论】：

【解决方案2】：

你可以得到解析a1和a2为JSONObject，然后改变值。

JSONObject jsonRootObj = JSON.parseObject(completeJson);
JSONObject a1 = jsonRootObj.getJSONObject("a1");
JSONObject a2 = jsonRootObj.getJSONObject("a2");
for (Map.Entry<String, Object> entry : a1.entrySet()) {
    if (a2.containsKey(entry.getKey())) {
        a2.put(entry.getKey(), entry.getValue());
    }
}

P.S：我的 JSON 解析器是 fastjson

【讨论】：

写作JSONObject a1 = jsonRootObj.getJSONObject("a1"); 抛出异常：- org.json.JSONException: JSONObject["a1"] not found.
你用的是哪个 JSON Parser
java-json.jar 是我添加到引用库中的文件。你能告诉我如何将 fastjson 添加到我的项目中吗？
可以在this link下载jar或者使用maven <dependency><groupId>com.alibaba</groupId><artifactId>fastjson</artifactId><version>1.2.14</version> </dependency>

【解决方案3】：

您的 JSON 字符串包含一个无名的根元素，从第一个 { 开始，到最后一个 } 结束。该对象将进入jsonRootObj 变量。要获取 a1 或 a2 对象，请执行以下操作：

JSONObject a1 = jsonRootObj.getJSONObject("a1");

要获取a1中第一个参赛者的值，可以这样做：

int marks = a1.getInt("Contestant 1 marks");

您可以找到 JSONObject here 的完整 Javadoc。不需要 JSON 数组。

【讨论】：

@AmitUpadhyay 您确定 completeJson 变量包含您在问题中发布的 JSON 代码吗？

【解决方案4】：

让您的生活更轻松。

下载gson library。

在项目上右击，Build Path->Add External Archives。

然后用你想要的任何名称创建一个类（我使用了 Example.java）：

import com.google.gson.annotations.Expose;
import com.google.gson.annotations.SerializedName;

public class Example {

    @SerializedName("a1")
    @Expose
    private A1 a1;
    @SerializedName("a2")
    @Expose
    private A2 a2;

    /**
     * @return The a1
     */
    public A1 getA1() {
        return a1;
    }

    /**
     * @param a1 The a1
     */
    public void setA1(A1 a1) {
        this.a1 = a1;
    }

    /**
     * @return The a2
     */
    public A2 getA2() {
        return a2;
    }

    /**
     * @param a2 The a2
     */
    public void setA2(A2 a2) {
        this.a2 = a2;
    }

    public class A1 {

        @SerializedName("Contestant 1 marks")
        @Expose
        private int contestant1Marks;
        @SerializedName("Contestant 10 marks")
        @Expose
        private int contestant10Marks;
        @SerializedName("Contestant 11 marks")
        @Expose
        private int contestant11Marks;
        @SerializedName("Contestant 12 marks")
        @Expose
        private int contestant12Marks;
        @SerializedName("Contestant 13 marks")
        @Expose
        private int contestant13Marks;
        @SerializedName("Contestant 14 marks")
        @Expose
        private int contestant14Marks;
        @SerializedName("Contestant 2 marks")
        @Expose
        private int contestant2Marks;
        @SerializedName("Contestant 3 marks")
        @Expose
        private float contestant3Marks;
        @SerializedName("Contestant 4 marks")
        @Expose
        private int contestant4Marks;
        @SerializedName("Contestant 5 marks")
        @Expose
        private int contestant5Marks;
        @SerializedName("Contestant 6 marks")
        @Expose
        private int contestant6Marks;
        @SerializedName("Contestant 7 marks")
        @Expose
        private int contestant7Marks;
        @SerializedName("Contestant 8 marks")
        @Expose
        private int contestant8Marks;
        @SerializedName("Contestant 9 marks")
        @Expose
        private int contestant9Marks;

        /**
         * @return The contestant1Marks
         */
        public int getContestant1Marks() {
            return contestant1Marks;
        }

        /**
         * @param contestant1Marks The Contestant 1 marks
         */
        public void setContestant1Marks(int contestant1Marks) {
            this.contestant1Marks = contestant1Marks;
        }

        /**
         * @return The contestant10Marks
         */
        public int getContestant10Marks() {
            return contestant10Marks;
        }

        /**
         * @param contestant10Marks The Contestant 10 marks
         */
        public void setContestant10Marks(int contestant10Marks) {
            this.contestant10Marks = contestant10Marks;
        }

        /**
         * @return The contestant11Marks
         */
        public int getContestant11Marks() {
            return contestant11Marks;
        }

        /**
         * @param contestant11Marks The Contestant 11 marks
         */
        public void setContestant11Marks(int contestant11Marks) {
            this.contestant11Marks = contestant11Marks;
        }

        /**
         * @return The contestant12Marks
         */
        public int getContestant12Marks() {
            return contestant12Marks;
        }

        /**
         * @param contestant12Marks The Contestant 12 marks
         */
        public void setContestant12Marks(int contestant12Marks) {
            this.contestant12Marks = contestant12Marks;
        }

        /**
         * @return The contestant13Marks
         */
        public int getContestant13Marks() {
            return contestant13Marks;
        }

        /**
         * @param contestant13Marks The Contestant 13 marks
         */
        public void setContestant13Marks(int contestant13Marks) {
            this.contestant13Marks = contestant13Marks;
        }

        /**
         * @return The contestant14Marks
         */
        public int getContestant14Marks() {
            return contestant14Marks;
        }

        /**
         * @param contestant14Marks The Contestant 14 marks
         */
        public void setContestant14Marks(int contestant14Marks) {
            this.contestant14Marks = contestant14Marks;
        }

        /**
         * @return The contestant2Marks
         */
        public int getContestant2Marks() {
            return contestant2Marks;
        }

        /**
         * @param contestant2Marks The Contestant 2 marks
         */
        public void setContestant2Marks(int contestant2Marks) {
            this.contestant2Marks = contestant2Marks;
        }

        /**
         * @return The contestant3Marks
         */
        public float getContestant3Marks() {
            return contestant3Marks;
        }

        /**
         * @param contestant3Marks The Contestant 3 marks
         */
        public void setContestant3Marks(float contestant3Marks) {
            this.contestant3Marks = contestant3Marks;
        }

        /**
         * @return The contestant4Marks
         */
        public int getContestant4Marks() {
            return contestant4Marks;
        }

        /**
         * @param contestant4Marks The Contestant 4 marks
         */
        public void setContestant4Marks(int contestant4Marks) {
            this.contestant4Marks = contestant4Marks;
        }

        /**
         * @return The contestant5Marks
         */
        public int getContestant5Marks() {
            return contestant5Marks;
        }

        /**
         * @param contestant5Marks The Contestant 5 marks
         */
        public void setContestant5Marks(int contestant5Marks) {
            this.contestant5Marks = contestant5Marks;
        }

        /**
         * @return The contestant6Marks
         */
        public int getContestant6Marks() {
            return contestant6Marks;
        }

        /**
         * @param contestant6Marks The Contestant 6 marks
         */
        public void setContestant6Marks(int contestant6Marks) {
            this.contestant6Marks = contestant6Marks;
        }

        /**
         * @return The contestant7Marks
         */
        public int getContestant7Marks() {
            return contestant7Marks;
        }

        /**
         * @param contestant7Marks The Contestant 7 marks
         */
        public void setContestant7Marks(int contestant7Marks) {
            this.contestant7Marks = contestant7Marks;
        }

        /**
         * @return The contestant8Marks
         */
        public int getContestant8Marks() {
            return contestant8Marks;
        }

        /**
         * @param contestant8Marks The Contestant 8 marks
         */
        public void setContestant8Marks(int contestant8Marks) {
            this.contestant8Marks = contestant8Marks;
        }

        /**
         * @return The contestant9Marks
         */
        public int getContestant9Marks() {
            return contestant9Marks;
        }

        /**
         * @param contestant9Marks The Contestant 9 marks
         */
        public void setContestant9Marks(int contestant9Marks) {
            this.contestant9Marks = contestant9Marks;
        }

    }

    public class A2 {

        @SerializedName("Contestant 1 marks")
        @Expose
        private int contestant1Marks;
        @SerializedName("Contestant 10 marks")
        @Expose
        private int contestant10Marks;
        @SerializedName("Contestant 11 marks")
        @Expose
        private int contestant11Marks;
        @SerializedName("Contestant 12 marks")
        @Expose
        private int contestant12Marks;
        @SerializedName("Contestant 13 marks")
        @Expose
        private int contestant13Marks;
        @SerializedName("Contestant 14 marks")
        @Expose
        private int contestant14Marks;
        @SerializedName("Contestant 2 marks")
        @Expose
        private int contestant2Marks;
        @SerializedName("Contestant 3 marks")
        @Expose
        private float contestant3Marks;
        @SerializedName("Contestant 4 marks")
        @Expose
        private int contestant4Marks;
        @SerializedName("Contestant 5 marks")
        @Expose
        private int contestant5Marks;
        @SerializedName("Contestant 6 marks")
        @Expose
        private int contestant6Marks;
        @SerializedName("Contestant 7 marks")
        @Expose
        private int contestant7Marks;
        @SerializedName("Contestant 8 marks")
        @Expose
        private int contestant8Marks;
        @SerializedName("Contestant 9 marks")
        @Expose
        private int contestant9Marks;

        /**
         * @return The contestant1Marks
         */
        public int getContestant1Marks() {
            return contestant1Marks;
        }

        /**
         * @param contestant1Marks The Contestant 1 marks
         */
        public void setContestant1Marks(int contestant1Marks) {
            this.contestant1Marks = contestant1Marks;
        }

        /**
         * @return The contestant10Marks
         */
        public int getContestant10Marks() {
            return contestant10Marks;
        }

        /**
         * @param contestant10Marks The Contestant 10 marks
         */
        public void setContestant10Marks(int contestant10Marks) {
            this.contestant10Marks = contestant10Marks;
        }

        /**
         * @return The contestant11Marks
         */
        public int getContestant11Marks() {
            return contestant11Marks;
        }

        /**
         * @param contestant11Marks The Contestant 11 marks
         */
        public void setContestant11Marks(int contestant11Marks) {
            this.contestant11Marks = contestant11Marks;
        }

        /**
         * @return The contestant12Marks
         */
        public int getContestant12Marks() {
            return contestant12Marks;
        }

        /**
         * @param contestant12Marks The Contestant 12 marks
         */
        public void setContestant12Marks(int contestant12Marks) {
            this.contestant12Marks = contestant12Marks;
        }

        /**
         * @return The contestant13Marks
         */
        public int getContestant13Marks() {
            return contestant13Marks;
        }

        /**
         * @param contestant13Marks The Contestant 13 marks
         */
        public void setContestant13Marks(int contestant13Marks) {
            this.contestant13Marks = contestant13Marks;
        }

        /**
         * @return The contestant14Marks
         */
        public int getContestant14Marks() {
            return contestant14Marks;
        }

        /**
         * @param contestant14Marks The Contestant 14 marks
         */
        public void setContestant14Marks(int contestant14Marks) {
            this.contestant14Marks = contestant14Marks;
        }

        /**
         * @return The contestant2Marks
         */
        public int getContestant2Marks() {
            return contestant2Marks;
        }

        /**
         * @param contestant2Marks The Contestant 2 marks
         */
        public void setContestant2Marks(int contestant2Marks) {
            this.contestant2Marks = contestant2Marks;
        }

        /**
         * @return The contestant3Marks
         */
        public float getContestant3Marks() {
            return contestant3Marks;
        }

        /**
         * @param contestant3Marks The Contestant 3 marks
         */
        public void setContestant3Marks(float contestant3Marks) {
            this.contestant3Marks = contestant3Marks;
        }

        /**
         * @return The contestant4Marks
         */
        public int getContestant4Marks() {
            return contestant4Marks;
        }

        /**
         * @param contestant4Marks The Contestant 4 marks
         */
        public void setContestant4Marks(int contestant4Marks) {
            this.contestant4Marks = contestant4Marks;
        }

        /**
         * @return The contestant5Marks
         */
        public int getContestant5Marks() {
            return contestant5Marks;
        }

        /**
         * @param contestant5Marks The Contestant 5 marks
         */
        public void setContestant5Marks(int contestant5Marks) {
            this.contestant5Marks = contestant5Marks;
        }

        /**
         * @return The contestant6Marks
         */
        public int getContestant6Marks() {
            return contestant6Marks;
        }

        /**
         * @param contestant6Marks The Contestant 6 marks
         */
        public void setContestant6Marks(int contestant6Marks) {
            this.contestant6Marks = contestant6Marks;
        }

        /**
         * @return The contestant7Marks
         */
        public int getContestant7Marks() {
            return contestant7Marks;
        }

        /**
         * @param contestant7Marks The Contestant 7 marks
         */
        public void setContestant7Marks(int contestant7Marks) {
            this.contestant7Marks = contestant7Marks;
        }

        /**
         * @return The contestant8Marks
         */
        public int getContestant8Marks() {
            return contestant8Marks;
        }

        /**
         * @param contestant8Marks The Contestant 8 marks
         */
        public void setContestant8Marks(int contestant8Marks) {
            this.contestant8Marks = contestant8Marks;
        }

        /**
         * @return The contestant9Marks
         */
        public int getContestant9Marks() {
            return contestant9Marks;
        }

        /**
         * @param contestant9Marks The Contestant 9 marks
         */
        public void setContestant9Marks(int contestant9Marks) {
            this.contestant9Marks = contestant9Marks;
        }

    }

}

之后，

String yourString = "json in String format";
Example example = new Gson().fromJson(yourString, Example.class);
example.getA1().getContestant1Marks();
example.getA2().getContestant1Marks();

就是这样。您可以使用这些 getter 方法。

PS：我使用 jsonschema2pojo 创建了这个类，方法是将你的 json 复制到其中。

编码愉快...!!!

【讨论】：

我的 java 项目中没有 gradle .. 我该怎么办？如果我在 android 中执行此操作，那么我将不得不从服务器获取 JSON 文件（但我没有服务器）
你能告诉我如何在eclipse项目中实现你的方法吗？
@Ayushibhardwaj 请查看此帖子：stackoverflow.com/a/31829107/1739882
@Ayushibhardwaj 你很容易得到 jar 文件。你已经准备好我的代码了。你只需要设法在你的项目中添加这个 jar 文件。试试看。。
@AmitUpadhyay 记住.. 这个 Example.java 模型仅适用于问题提供的 JSON。如果您的 JSON 与此不同，则需要从我提到的网站创建另一个模型。