A Minimalist HTTP Client for Java: One‑Line External Requests with OKHttpUtil

OKHttpUtil

OKHttpUtil provides a thin wrapper over Square's OkHttp library, offering a lightweight and easy‑to‑use HTTP client for Java and Kotlin.

Features

Automatically selects HTTP or HTTPS based on the URL.

Cookies are recorded by default, enabling simulated login flows.

Detects 304 redirects and follows them automatically.

Supports proxy configuration.

Allows custom User‑Agent headers.

Decompresses GZIP‑encoded responses.

Integrates with Spring Boot via a starter.

Provides a minimal one‑line invocation API.

Maven Dependency

<dependency>
    <groupId>io.github.admin4j</groupId>
    <artifactId>http</artifactId>
    <version>0.4.0</version>
</dependency>

Latest version: https://search.maven.org/artifact/io.github.admin4j/http

GET Request Example

Response response = HttpUtil.get(
    "https://github.com/search",
    Pair.of("q", "okhttp")
);
System.out.println("response = " + response);

POST Request Example

# JSON body
Response post = HttpUtil.post(
    "https://oapi.dingtalk.com/robot/send?access_token=YOUR_TOKEN",
    "{\"msgtype\":\"text\",\"text\":{\"content\":\"[Feedback] I am unique\"}}"
);
System.out.println("post = " + post);

# Form request
Map<String, Object> formParams = new HashMap<>(16);
formParams.put("username", "admin");
formParams.put("password", "admin123");
Response response = HttpUtil.postForm(
    "http://192.168.1.13:9100/auth/login",
    formParams
);
System.out.println("response = " + response);

JSON Response Handling

When the response is JSON, HttpJsonUtil returns a JSONObject directly:

JSONObject object = HttpJsonUtil.get(
    "https://github.com/search",
    Pair.of("q", "http"),
    Pair.of("username", "agonie201218")
);
System.out.println("object = " + object);

File Upload and Download

// Upload
File file = new File("C:\\Users\\andanyang\\Downloads\\Sql.txt");
Map<String, Object> formParams = new HashMap<>();
formParams.put("key", "test");
formParams.put("file", file);
formParams.put("token", "YOUR_TOKEN");
Response uploadResponse = HttpUtil.upload(
    "https://upload.qiniup.com/",
    formParams
);
System.out.println(uploadResponse);

// Download
HttpUtil.down(
    "https://gitee.com/admin4j/common-http",
    "path/"
);

Spring Boot Integration

Add the starter dependency:

<dependency>
    <groupId>io.github.admin4j</groupId>
    <artifactId>common-http-starter</artifactId>
    <version>0.4.0</version>
</dependency>

Configure the client with a POJO:

public class HttpConfig {
    private HttpLoggingInterceptor.Level loggLevel = HttpLoggingInterceptor.Level.BODY;
    private long readTimeout = 30;          // seconds
    private long connectTimeout = 30;      // seconds
    private boolean followRedirects = false;
    private int maxIdleConnections = 5;
    private long keepAliveDuration = 5;    // seconds
    private String userAgent = "OKHTTP";
    private boolean cookie = false;
    private ProxyConfig proxy;
}

@Data
public static class ProxyConfig {
    private Proxy.Type type = Proxy.Type.HTTP;
    private String host;
    private Integer port = 80;
    private String userName;
    private String password;
}

Chainable Requests with HttpRequest

# GET chain
Response r = HttpRequest.get("https://search.gitee.com/?skin=rec&type=repository")
    .queryMap("q", "admin4j")
    .header(HttpHeaderKey.USER_AGENT, "admin4j")
    .execute();
System.out.println("response = " + r);

# POST form chain
Response r2 = HttpRequest.get("http://192.168.1.13:9100/auth/login")
    .queryMap("q", "admin4j")
    .header(HttpHeaderKey.USER_AGENT, "admin4j")
    .form("username", "admin")
    .form("password", "admin123")
    .execute();
System.out.println("response = " + r2);

Quick External API Encapsulation

Example of wrapping eBay REST APIs with a base client and specialized subclasses.

public class EbayClient extends ApiJsonClient {
    public EbayClient(Long storeId) {
        // TODO: load store configuration
        basePath = "https://api.ebay.com";
        defaultHeaderMap.put("Authorization", "Bearer " + config.get("accessToken"));
        defaultHeaderMap.put("X-EBAY-C-MARKETPLACE-ID", config.get("marketplaceId"));
    }
}

public class EbayInventoryClient extends EbayClient {
    public EbayInventoryClient(Long storeId) { super(storeId); }
    public JSONObject inventoryItem(Integer limit, Integer offset) throws IOException {
        Map<String, Object> query = new HashMap<>(2);
        query.put("limit", limit);
        query.put("offset", offset);
        return get("/sell/inventory/v1/inventory_item", query);
    }
}

EbayInventoryClient client = new EbayInventoryClient(1L);
JSONObject json = client.inventoryItem(0, 10);

Source code repository: https://github.com/admin4j/common-http