使用GSON API解析JSON，提取Resources数组中的JsonObject

Got it, let's walk through exactly how to pull each element from the Resources array as a com.google.gson.JsonObject—perfect for feeding into your existing method that requires this type. Here's a step-by-step solution tailored to your SCIM JSON response:

1. 确认Gson依赖已引入 #

First, make sure you have the latest stable Gson dependency in your project:

• For Maven, add this to your pom.xml:

<dependency>
    <groupId>com.google.code.gson</groupId>
    <artifactId>gson</artifactId>
    <version>2.10.1</version> <!-- Use the latest stable version available -->
</dependency>

• For Gradle, add this to your build.gradle:

implementation 'com.google.code.gson:gson:2.10.1'

2. 核心代码实现 #

Here's the full code to parse your JSON string, extract the Resources array, and loop through each element as a JsonObject:

import com.google.gson.JsonArray;
import com.google.gson.JsonObject;
import com.google.gson.JsonParser;

public class ScimEntitlementProcessor {
    public static void main(String[] args) {
        // Your input JSON string (the one you provided)
        String scimJsonResponse = "{ \"totalResults\": 2, \"startIndex\": 1, \"schemas\": [ \"urn:ietf:params:scim:api:messages:2.0:ListResponse\" ], \"Resources\": [ { \"owner\": {}, \"application\": { \"displayName\": \"Non Auth App\", \"value\": \"4028b88168fa3d38016900d1759405a6\", \"$ref\": \"http://localhost:8080/identityiq/scim/v2/Applications/4028b88168fa3d38016900d1759405a6\" }, \"meta\": { \"created\": \"2019-03-22T18:40:30.505+05:30\", \"location\": \"http://localhost:8080/identityiq/scim/v2/Entitlements/297eff8a699f8b3a0169a5863769008b\", \"version\": \"W/\\\"1553260230505\\\"\", \"resourceType\": \"Entitlement\" }, \"schemas\": [ \"urn:ietf:params:scim:schemas:sailpoint:1.0:Entitlement\" ], \"displayableName\": \"reader\", \"aggregated\": false, \"id\": \"297eff8a699f8b3a0169a5863769008b\", \"requestable\": true, \"attribute\": \"Privileges\", \"type\": \"Entitlement\", \"descriptions\": [], \"value\": \"reader\" }, { \"owner\": {}, \"application\": { \"displayName\": \"Non Auth App\", \"value\": \"4028b88168fa3d38016900d1759405a6\", \"$ref\": \"http://localhost:8080/identityiq/scim/v2/Applications/4028b88168fa3d38016900d1759405a6\" }, \"meta\": { \"created\": \"2019-03-18T19:11:47.912+05:30\", \"location\": \"http://localhost:8080/identityiq/scim/v2/Entitlements/297eff8a6990fc49016991096d08001e\", \"version\": \"W/\\\"1552916507912\\\"\", \"resourceType\": \"Entitlement\" }, \"schemas\": [ \"urn:ietf:params:scim:schemas:sailpoint:1.0:Entitlement\" ], \"displayableName\": \"admin\", \"aggregated\": false, \"id\": \"297eff8a6990fc49016991096d08001e\", \"requestable\": true, \"attribute\": \"Privileges\", \"type\": \"Entitlement\", \"descriptions\": [], \"value\": \"admin\" } ] }";

        // Step 1: Parse the JSON string into the root JsonObject
        JsonObject rootJsonObject = JsonParser.parseString(scimJsonResponse).getAsJsonObject();

        // Step 2: Extract the Resources array from the root object
        JsonArray resourcesArray = rootJsonObject.getAsJsonArray("Resources");

        // Step 3: Loop through each element in the array and cast to JsonObject
        for (int i = 0; i < resourcesArray.size(); i++) {
            // Each element in Resources is a JSON object, so safely cast to JsonObject
            JsonObject entitlementJsonObject = resourcesArray.get(i).getAsJsonObject();

            // Pass the JsonObject to your existing method here
            processEntitlement(entitlementJsonObject);
        }
    }

    // Example method that accepts a JsonObject (replace with your actual method)
    private static void processEntitlement(JsonObject entitlement) {
        // Extract example attributes to demonstrate usage
        String entitlementId = entitlement.get("id").getAsString();
        String displayName = entitlement.get("displayableName").getAsString();
        String appValue = entitlement.getAsJsonObject("application").get("value").getAsString();

        System.out.printf("Processed Entitlement: ID=%s, Name=%s, App ID=%s%n", 
                          entitlementId, displayName, appValue);
    }
}

3. 关键说明 #

• 安全类型转换: 你的SCIM响应中Resources数组的每个元素都是JSON对象，因此getAsJsonObject()可以安全使用，不会出现类型不匹配问题。
• 可扩展性: 循环可以处理任意数量的数组元素，不管是示例中的2个还是成百上千个。
• 现代Gson用法: JsonParser.parseString()是Gson 2.8+版本推荐的解析方式，替代了已废弃的new JsonParser().parse()方法。

内容的提问来源于stack exchange，提问作者Barca Fan