Java SDK integration guide - HTTPDNS - Alibaba Cloud Documentation Center

The Client integration overview topic explains the basic principles of HTTPDNS integration. This guide describes how to use the Java SDK to perform the integration.

Important

For Android applications, see the Android SDK integration guide. The Java SDK does not support Android-specific features, such as a local persistent cache or automatic parsing upon network changes.

1. Getting started

1.1. Activate the service

See Quick Start to activate HTTPDNS.

1.2. Get configurations

Obtain your AccountId, SecretKey, and AESSecretKey from the Developer Configurations page in the EMAS console. This information is required to initialize the SDK. For more information, see Developer configurations.

2. Installation and configuration

Configure your project using either Gradle or Maven, depending on your build tool.

2.1. Configure the repository address

The SDK is published to the Alibaba Cloud Maven repository. Add the repository address.

Gradle

Add the following code to your settings.gradle or build.gradle file:

repositories {
    maven { 
      url 'https://maven.aliyun.com/nexus/content/repositories/releases/' 
    }
}

Maven

Add the following code to your pom.xml file:

<repositories>
    <repository>
        <id>aliyun</id>
        <url>https://maven.aliyun.com/nexus/content/repositories/releases/</url>
    </repository>
</repositories>

2.2. Add the SDK dependency

Gradle

In your build.gradle file, add the following code to the dependencies block:

dependencies {
    implementation 'com.aliyun.ams:alicloud-java-httpdns:1.0.0'
}

Maven

In your pom.xml file, add the following code to the <dependencies> block:

<dependency>
    <groupId>com.aliyun.ams</groupId>
    <artifactId>alicloud-java-httpdns</artifactId>
    <version>1.0.0</version>
</dependency>

3. Configuration and usage

3.1. Initialize configurations

After your application starts, initialize the SDK to enable HTTPDNS features. Initialization involves configuring settings such as your AccountId, SecretKey, and feature toggles. The following code provides an example:

import com.alibaba.sdk.java.httpdns.HttpDnsClient;
import com.alibaba.sdk.java.httpdns.InitConfig;
import com.alibaba.sdk.java.httpdns.RequestIpType;

// Create a configuration.
InitConfig config = new InitConfig.Builder()
    .setSecretKey("your-secret-key")           // Signing key
    .setEnableHttps(true)                      // Use HTTPS for resolution.
    .setTimeoutMillis(2000)                    // Timeout period in milliseconds.
    .setEnableExpiredIp(true)                  // Allow the use of expired IPs.
    .enableMemoryCache(true)                   // Enable memory cache (enabled by default).
    .build();

// Initialize.
HttpDnsClient.init("your-account-id", config);

// Get the client instance.
HttpDnsClient client = HttpDnsClient.getClient("your-account-id");

Important

Enabling HTTPS by setting the setEnableHttps parameter to true incurs additional costs. For more information, see Billing.
If you require higher security for domain name information or SDNS parameters, you can set the setAesSecretKey parameter to enable content-layer encryption for resolution requests. This feature incurs additional costs. For more information, see Billing.

3.1.1. Configure logs

During application development, configure HttpDnsLog to output HTTPDNS logs:

import com.alibaba.sdk.java.httpdns.log.HttpDnsLog;
import com.alibaba.sdk.java.httpdns.ILogger;

// Enable log output.
HttpDnsLog.enable(true);

// Set a custom logging interface.
HttpDnsLog.setLogger(new ILogger() {
    @Override
    public void log(String msg) {
        System.out.println("[HTTPDNS] " + msg);
    }
});

3.1.2. Record the SessionId

While your application is running, retrieve the sessionId and record it in your data ingestion system to help troubleshoot online issues:

String sessionId = client.getSessionId();
System.out.println("SessionId = " + sessionId);

3.2. Domain name resolution

3.2.1 Pre-parsing

After you initialize HTTPDNS, you can configure pre-resolution for frequently accessed hot spot domain names. This allows the SDK to resolve them in advance and reduces latency for future resolution requests. The following code provides an example:

List<String> hosts = Arrays.asList("www.aliyun.com", "www.example.com");
client.setPreResolveHosts(hosts, RequestIpType.both);

3.2.2. Resolve a domain name

To resolve a domain name, call the domain name resolution method to retrieve the IP address. The following code provides an example:

HTTPDNSResult result = client.getHttpDnsResultForHostSyncNonBlocking(
    "www.aliyun.com", 
    RequestIpType.both
);

if (result != null && result.getIps() != null) {
    String[] ipv4List = result.getIps();
}

if (result != null && result.getIpv6s() != null) {
    String[] ipv6List = result.getIpv6s();
}

4. What to do next

After you retrieve an IP address, apply it to your network requests. Depending on the network library you use, see Best practices for HTTPDNS and OkHttp in Java or Best practices for HTTPDNS and Apache HttpClient in Java.

To configure the SDK in more detail or use other features such as authentication requests, see Java SDK API.

5. Notes

Compilation fails after an SDK upgrade
If compilation fails after you upgrade the SDK, the SDK API may have changed. See the Java SDK API and use the new replacement interfaces.
Write fallback code
You must include fallback code. If HTTPDNS fails to return the expected result, your application must fall back to using the local DNS for domain name resolution.
Record the IP address and sessionId from HTTPDNS
We provide a solution to troubleshoot resolution issues. You must record the IP address and sessionId obtained from HTTPDNS in your logs. For more information, see How to use the session tracking solution to troubleshoot resolution errors.