API 要求
透過集合功能整理內容
你可以依據偏好儲存及分類內容。
設定專案,為您的服務宣告依附元件後
Google API Java 專用用戶端程式庫,請按照下列步驟提出要求。
本頁面的程式碼片段使用 Cloud Resource Manager API 第 3 版。
步驟 1:驗證
例項化
com.google.auth.oauth2.GoogleCredentials
敬上
執行個體。Google Cloud 使用者可使用
GoogleCredentials.getApplicationDefault()
敬上
來取得
應用程式預設憑證。
GoogleCredentials credentials = GoogleCredentials.getApplicationDefault();
如要進一步瞭解驗證,請參閱
Google 驗證程式庫 Java。
步驟 2:將服務類別例項化
Google 服務有一或多個版本。服務類別代表版本
也是某項服務的子項類別
AbstractGoogleJsonClient。
例如:
com.google.api.services.cloudresourcemanager.v3.CloudResourceManager
。
服務類別的建構工具類別會使用 3 個參數:
也使用您的應用程式呼叫建構工具的 setApplicationName()
方法
名稱。這會使用應用程式名稱設定 UserAgent 標頭,因此非常實用
。
程式碼如下所示:
HttpTransport transport = GoogleNetHttpTransport.newTrustedTransport();
JsonFactory jsonFactory = GsonFactory.getDefaultInstance();
CloudResourceManager.Builder resourceManagerBuilder =
new CloudResourceManager.Builder(
transport, jsonFactory, new HttpCredentialsAdapter(credentials))
.setApplicationName("Example Java App");
CloudResourceManager cloudResourceManager = resourceManagerBuilder.build();
步驟 3:建立資源物件
資源類別代表資源的類型
透過 Cloud Run
類別會定義為服務類別的內部類別。您可以存取
來解決問題
舉例來說,您可以取得CloudResourceManager 的資源
類別:
import com.google.api.services.cloudresourcemanager.v3.CloudResourceManager.Projects;
...
Projects projects = cloudResourceManager.projects();
步驟 4:建立要求物件
對資源物件的作業會以要求類別表示。
可用的作業視資源類別而定。例如資源
提供「create」、「get」和「delete」的類別方法包含
「建立」、「取得」和「刪除」要求類別。
以 Cloud Resource Manager 為例,您可以
呼叫 projects.get
方法:
Get get = projects.get("projects/your-project-id");
步驟 5:執行要求
要求物件包含可執行要求的 execute()
方法。這場通話
對 Google 服務執行 HTTP 要求,並將 JSON 還原序列化
傳給模型類別的回應例如:GET 的 execute()
方法
要求物件會傳回 Project 物件:
Project project = get.execute();
System.out.println("Project name: " + project.getDisplayName());
摘要
透過這些步驟,您可以使用 Google API 用戶端程式庫,為
Java。以下程式碼片段結合了所有步驟,使用資源
管理員服務。
package com.example;
import com.google.api.client.googleapis.javanet.GoogleNetHttpTransport;
import com.google.api.client.http.HttpTransport;
import com.google.api.client.json.JsonFactory;
import com.google.api.client.json.gson.GsonFactory;
import com.google.api.services.cloudresourcemanager.v3.CloudResourceManager;
import com.google.api.services.cloudresourcemanager.v3.CloudResourceManager.Projects;
import com.google.api.services.cloudresourcemanager.v3.CloudResourceManager.Projects.Get;
import com.google.api.services.cloudresourcemanager.v3.model.Project;
import com.google.auth.http.HttpCredentialsAdapter;
import com.google.auth.oauth2.GoogleCredentials;
public class ResourceManagerSample {
public static void main(String[] arguments) throws Exception {
GoogleCredentials credentials = GoogleCredentials.getApplicationDefault();
HttpTransport transport = GoogleNetHttpTransport.newTrustedTransport();
JsonFactory jsonFactory = GsonFactory.getDefaultInstance();
CloudResourceManager.Builder resourceManagerBuilder =
new CloudResourceManager.Builder(
transport, jsonFactory, new HttpCredentialsAdapter(credentials))
.setApplicationName("Example Java App");
CloudResourceManager cloudResourceManager = resourceManagerBuilder.build();
Projects projects = cloudResourceManager.projects();
Get get = projects.get("projects/your-project-id");
Project project = get.execute();
System.out.println("Project display name: " + project.getDisplayName());
}
}
除非另有註明,否則本頁面中的內容是採用創用 CC 姓名標示 4.0 授權,程式碼範例則為阿帕契 2.0 授權。詳情請參閱《Google Developers 網站政策》。Java 是 Oracle 和/或其關聯企業的註冊商標。
上次更新時間:2025-07-26 (世界標準時間)。
[null,null,["上次更新時間:2025-07-26 (世界標準時間)。"],[[["\u003cp\u003eThis guide provides a step-by-step approach to making requests to Google APIs using the Google APIs Client Library for Java, covering authentication, service instantiation, resource object creation, request object creation, and request execution.\u003c/p\u003e\n"],["\u003cp\u003eDevelopers will learn how to authenticate using GoogleCredentials, instantiate service classes to interact with specific Google APIs, and create resource objects to access specific API resources.\u003c/p\u003e\n"],["\u003cp\u003eYou'll be able to utilize request objects to perform operations on resources, with a working example demonstrating the process using the Cloud Resource Manager service to retrieve project details.\u003c/p\u003e\n"],["\u003cp\u003eThe provided code examples allow developers to easily adapt the steps for their own applications and make API requests efficiently.\u003c/p\u003e\n"]]],[],null,["# API Requests\n\nOnce you set up your project to [declare the dependencies](/api-client-library/java/google-api-java-client/setup) for your\nGoogle APIs Client Library for Java, follow these steps to make a request.\nThe snippets in this page uses v3 of the Cloud Resource Manager API.\n\nStep 1: Authentication\n----------------------\n\nInstantiate\n[`com.google.auth.oauth2.GoogleCredentials`](https://cloud.google.com/java/docs/reference/google-auth-library/latest/com.google.auth.oauth2.GoogleCredentials)\ninstance. For Google Cloud users, you may use\n[`GoogleCredentials.getApplicationDefault()`](https://cloud.google.com/java/docs/reference/google-auth-library/latest/com.google.auth.oauth2.GoogleCredentials#com_google_auth_oauth2_GoogleCredentials_getApplicationDefault__)\nto get the\n[Application Default Credentials](https://cloud.google.com/docs/authentication/provide-credentials-adc). \n\n GoogleCredentials credentials = GoogleCredentials.getApplicationDefault();\n\nFor more information on authentication, refer to\n[Google Auth Library Java](https://github.com/googleapis/google-auth-library-java?tab=readme-ov-file#using-credentials-with-google-http-client).\n\nStep 2: Instantiate Service Class\n---------------------------------\n\nA Google service has one or more versions. A service class represents a version\nof a service and is a child class of\n[AbstractGoogleJsonClient](https://cloud.google.com/java/docs/reference/google-api-client/latest/com.google.api.client.googleapis.services.json.AbstractGoogleJsonClient).\nFor example\n`com.google.api.services.cloudresourcemanager.v3.CloudResourceManager`.\n\nThe builder class of the service class takes 3 parameters:\n\n- [`com.google.api.client.http.HttpTransport`](https://cloud.google.com/java/docs/reference/google-http-client/latest/com.google.api.client.http.HttpTransport). [`GoogleNetHttpTransport.newTrustedTransport()`](https://cloud.google.com/java/docs/reference/google-api-client/latest/com.google.api.client.googleapis.javanet.GoogleNetHttpTransport#com_google_api_client_googleapis_javanet_GoogleNetHttpTransport_newTrustedTransport__) creates an instance of it.\n- [`com.google.api.client.json.JsonFactory`](https://cloud.google.com/java/docs/reference/google-http-client/latest/com.google.api.client.json.JsonFactory). [`GsonFactory.getDefaultInstance()`](https://cloud.google.com/java/docs/reference/google-http-client/latest/com.google.api.client.json.gson.GsonFactory#com_google_api_client_json_gson_GsonFactory_getDefaultInstance__) creates an instance of it.\n- [`com.google.api.client.http.HttpRequestInitializer`](https://cloud.google.com/java/docs/reference/google-http-client/latest/com.google.api.client.http.HttpRequestInitializer). [`new HttpCredentialsAdapter(credentials)`](https://cloud.google.com/java/docs/reference/google-auth-library/latest/com.google.auth.http.HttpCredentialsAdapter) gives an instance of it.\n\nAlso call `setApplicationName()` method of the builder with your application\nname. This sets the UserAgent header with the application name and is helpful\nfor troubleshooting with logs.\n\nThe code looks like: \n\n HttpTransport transport = GoogleNetHttpTransport.newTrustedTransport();\n JsonFactory jsonFactory = GsonFactory.getDefaultInstance();\n CloudResourceManager.Builder resourceManagerBuilder =\n new CloudResourceManager.Builder(\n transport, jsonFactory, new HttpCredentialsAdapter(credentials))\n .setApplicationName(\"Example Java App\");\n CloudResourceManager cloudResourceManager = resourceManagerBuilder.build();\n\nStep 3: Create a Resource Object\n--------------------------------\n\nA resource class represents a type of [the resource](https://cloud.google.com/apis/design/resources)\nmanaged by a service.\nThe class is defined as an inner class of the service class. You can access them\nusing the methods in the service class.\n\nFor example, you can get the \"Projects\" resource of the CloudResourceManager\nclass: \n\n import com.google.api.services.cloudresourcemanager.v3.CloudResourceManager.Projects;\n\n ...\n\n Projects projects = cloudResourceManager.projects();\n\nStep 4: Make a Request Object\n-----------------------------\n\nThe operations against the resource object are represented as request classes.\nThe available operations depend on the resource class. For example, a resource\nclass that provides \"create\", \"get\", and \"delete\" methods contain\n\"Create\", \"Get\", and \"Delete\" request classes respectively.\n\nFor Cloud Resource Manager's example, you can make the Get request object by\ncalling `projects.get` method: \n\n Get get = projects.get(\"projects/your-project-id\");\n\nStep 5: Execute the Request\n---------------------------\n\nA request object has the `execute()` method that runs the request. This call\nexecutes an HTTP request to the Google service and deserializes the JSON\nresponse to a model class. For example, the `execute()` method of the Get\nrequest object returns a Project object: \n\n Project project = get.execute();\n System.out.println(\"Project name: \" + project.getDisplayName());\n\nSummary\n-------\n\nWith these steps, you can make requests using Google APIs Client Library for\nJava. Here is the code snippet that combines all the steps using the Resource\nManager service. \n\n package com.example;\n\n import com.google.api.client.googleapis.javanet.GoogleNetHttpTransport;\n import com.google.api.client.http.HttpTransport;\n import com.google.api.client.json.JsonFactory;\n import com.google.api.client.json.gson.GsonFactory;\n import com.google.api.services.cloudresourcemanager.v3.CloudResourceManager;\n import com.google.api.services.cloudresourcemanager.v3.CloudResourceManager.Projects;\n import com.google.api.services.cloudresourcemanager.v3.CloudResourceManager.Projects.Get;\n import com.google.api.services.cloudresourcemanager.v3.model.Project;\n import com.google.auth.http.HttpCredentialsAdapter;\n import com.google.auth.oauth2.GoogleCredentials;\n\n public class ResourceManagerSample {\n public static void main(String[] arguments) throws Exception {\n GoogleCredentials credentials = GoogleCredentials.getApplicationDefault();\n\n HttpTransport transport = GoogleNetHttpTransport.newTrustedTransport();\n JsonFactory jsonFactory = GsonFactory.getDefaultInstance();\n CloudResourceManager.Builder resourceManagerBuilder =\n new CloudResourceManager.Builder(\n transport, jsonFactory, new HttpCredentialsAdapter(credentials))\n .setApplicationName(\"Example Java App\");\n CloudResourceManager cloudResourceManager = resourceManagerBuilder.build();\n\n Projects projects = cloudResourceManager.projects();\n\n Get get = projects.get(\"projects/your-project-id\");\n\n Project project = get.execute();\n System.out.println(\"Project display name: \" + project.getDisplayName());\n }\n }"]]