<dependency>
    <groupId>com.squareup.okhttp3</groupId>
    <artifactId>okhttp</artifactId>
    <version>4.12.0</version>
</dependency>

import okhttp3.OkHttpClient;

public class OkHttpConfig {
    // 全局唯一的OkHttpClient實(shí)例
    private static final OkHttpClient client = new OkHttpClient();

    public static OkHttpClient getClient() {
        return client;
    }
}

import okhttp3.*;

public class GetExample {
    public static void main(String[] args) throws Exception {
        // 1. 創(chuàng)建一個(gè)Request對(duì)象，指定URL
        Request request = new Request.Builder()
                .url("https://jsonplaceholder.typicode.com/posts/1")
                .build();

        // 2. 使用OkHttpClient執(zhí)行請(qǐng)求，獲取Response
        try (Response response = OkHttpConfig.getClient().newCall(request).execute()) {
            if (!response.isSuccessful()) throw new IOException("Unexpected code " + response);

            // 3. 讀取響應(yīng)體中的文本內(nèi)容
            String responseBody = response.body().string();
            System.out.println("Response: " + responseBody);
        }
    }
}

import okhttp3.FormBody;
import okhttp3.RequestBody;

public class PostFormExample {
    public static void main(String[] args) throws Exception {
        // 1. 構(gòu)建表單數(shù)據(jù)體
        RequestBody formBody = new FormBody.Builder()
                .add("username", "john_doe")
                .add("email", "john@example.com")
                .build();

        // 2. 創(chuàng)建POST請(qǐng)求，將表單數(shù)據(jù)體附加到請(qǐng)求中
        Request request = new Request.Builder()
                .url("https://httpbin.org/post")
                .post(formBody)
                .build();

        // 3. 執(zhí)行請(qǐng)求
        try (Response response = OkHttpConfig.getClient().newCall(request).execute()) {
            if (!response.isSuccessful()) throw new IOException("Unexpected code " + response);

            String responseBody = response.body().string();
            System.out.println("Response: " + responseBody);
        }
    }
}

import okhttp3.MediaType;
import okhttp3.RequestBody;

public class PostJsonExample {
    public static void main(String[] args) throws Exception {
        // 1. 定義JSON媒體類(lèi)型
        MediaType JSON = MediaType.get("application/json; charset=utf-8");

        // 2. 構(gòu)建JSON字符串作為請(qǐng)求體
        String json = "{\"name\": \"Alice\", \"age\": 30}";

        // 3. 創(chuàng)建RequestBody
        RequestBody body = RequestBody.create(json, JSON);

        // 4. 創(chuàng)建POST請(qǐng)求，附帶請(qǐng)求體
        Request request = new Request.Builder()
                .url("https://httpbin.org/post")
                .post(body)
                .build();

        // 5. 執(zhí)行請(qǐng)求
        try (Response response = OkHttpConfig.getClient().newCall(request).execute()) {
            if (!response.isSuccessful()) throw new IOException("Unexpected code " + response);

            String responseBody = response.body().string();
            System.out.println("Response: " + responseBody);
        }
    }
}

import okhttp3.MultipartBody;

public class UploadFileExample {
    public static void main(String[] args) throws Exception {
        // 1. 創(chuàng)建MultipartBody.Builder來(lái)構(gòu)建多部分表單
        MultipartBody.Builder multipartBuilder = new MultipartBody.Builder()
                .setType(MultipartBody.FORM); // 指定為form-data

        // 2. 添加文件部分：需要提供文件路徑和文件名（可選）
        File file = new File("path/to/your/file.txt");
        multipartBuilder.addFormDataPart("file", file.getName(), 
                RequestBody.create(MediaType.parse("text/plain"), file));

        // 3. 添加其他表單字段（可選）
        multipartBuilder.addFormDataPart("description", "This is a test file.");

        // 4. 構(gòu)建完整的RequestBody
        RequestBody requestBody = multipartBuilder.build();

        // 5. 創(chuàng)建POST請(qǐng)求，使用multipart/form-data
        Request request = new Request.Builder()
                .url("https://httpbin.org/post")
                .post(requestBody)
                .build();

        // 6. 執(zhí)行請(qǐng)求
        try (Response response = OkHttpConfig.getClient().newCall(request).execute()) {
            if (!response.isSuccessful()) throw new IOException("Unexpected code " + response);

            String responseBody = response.body().string();
            System.out.println("Response: " + responseBody);
        }
    }
}

import okhttp3.Callback;
import okhttp3.Response;

public class AsyncRequestExample {
    public static void main(String[] args) {
        Request request = new Request.Builder()
                .url("https://jsonplaceholder.typicode.com/posts/1")
                .build();

        // 1. 使用enqueue方法發(fā)送異步請(qǐng)求，傳入Callback
        OkHttpConfig.getClient().newCall(request).enqueue(new Callback() {
            @Override
            public void onFailure(Call call, IOException e) {
                // 請(qǐng)求失敗時(shí)的回調(diào)，例如網(wǎng)絡(luò)錯(cuò)誤、超時(shí)等
                System.err.println("Request failed: " + e.getMessage());
                e.printStackTrace();
            }

            @Override
            public void onResponse(Call call, Response response) throws IOException {
                // 請(qǐng)求成功時(shí)的回調(diào)，此時(shí)response已經(jīng)可用
                if (!response.isSuccessful()) {
                    System.err.println("Unexpected code " + response);
                    return;
                }

                // 讀取響應(yīng)體內(nèi)容
                String responseBody = response.body().string();
                System.out.println("Async Response: " + responseBody);

                // 重要：必須關(guān)閉response.body()，否則可能造成資源泄漏！
                // 因?yàn)檫@里是在回調(diào)里，所以不能用try-with-resources，需要手動(dòng)關(guān)閉。
                // 但請(qǐng)注意，在實(shí)際項(xiàng)目中，應(yīng)確保此邏輯的健壯性。
                response.close();
            }
        });

        // 2. 注意：主線程不會(huì)等待異步請(qǐng)求完成，會(huì)立即繼續(xù)執(zhí)行后續(xù)代碼。
        // 這里為了演示，可以加一個(gè)sleep，讓程序運(yùn)行一段時(shí)間。
        try {
            Thread.sleep(5000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
}

import okhttp3.Interceptor;
import okhttp3.Request;
import okhttp3.Response;

public class LoggingInterceptor implements Interceptor {
    @Override
    public Response intercept(Chain chain) throws IOException {
        // 1. 獲取原始請(qǐng)求
        Request request = chain.request();

        // 2. 記錄請(qǐng)求信息（時(shí)間、方法、URL、Headers）
        long startTime = System.currentTimeMillis();
        System.out.println("Sending request to: " + request.url());
        System.out.println("Method: " + request.method());
        System.out.println("Headers: " + request.headers());

        // 3. 繼續(xù)執(zhí)行請(qǐng)求（關(guān)鍵步驟）
        Response response = chain.proceed(request);

        // 4. 記錄響應(yīng)信息（狀態(tài)碼、耗時(shí)、響應(yīng)體大?。?
        long endTime = System.currentTimeMillis();
        System.out.println("Received response in " + (endTime - startTime) + "ms");
        System.out.println("Status Code: " + response.code());
        System.out.println("Response Body Size: " + response.body().contentLength() + " bytes");

        // 5. 返回修改后的響應(yīng)（通常不需要修改，直接返回原響應(yīng)）
        return response;
    }
}

// 1. 為OkHttpClient添加攔截器（注意：攔截器分為兩種：Application Interceptor & Network Interceptor）
// 這里我們使用Application Interceptor，它會(huì)在請(qǐng)求發(fā)出前和響應(yīng)返回后各執(zhí)行一次。
OkHttpClient client = new OkHttpClient.Builder()
        .addInterceptor(new LoggingInterceptor())
        .build();

// 2. 使用這個(gè)帶有攔截器的client進(jìn)行請(qǐng)求，日志就會(huì)自動(dòng)打印出來(lái)。

import okhttp3.Interceptor;
import okhttp3.Request;
import okhttp3.Response;

public class AuthInterceptor implements Interceptor {
    private final String token;

    public AuthInterceptor(String token) {
        this.token = token;
    }

    @Override
    public Response intercept(Chain chain) throws IOException {
        // 1. 獲取原始請(qǐng)求
        Request originalRequest = chain.request();

        // 2. 創(chuàng)建一個(gè)新的請(qǐng)求，添加Authorization Header
        Request authenticatedRequest = originalRequest.newBuilder()
                .header("Authorization", "Bearer " + token)
                .build();

        // 3. 繼續(xù)執(zhí)行帶有認(rèn)證頭的請(qǐng)求
        return chain.proceed(authenticatedRequest);
    }
}

// 應(yīng)用該攔截器，確保所有請(qǐng)求都攜帶Token
OkHttpClient client = new OkHttpClient.Builder()
        .addInterceptor(new AuthInterceptor("your-jwt-token-here"))
        .build();

import okhttp3.*;
import java.io.IOException;
import java.util.concurrent.TimeUnit;

public class UserLoginApp {
    private static final OkHttpClient client = new OkHttpClient.Builder()
            .connectTimeout(10, TimeUnit.SECONDS) // 連接超時(shí)10秒
            .readTimeout(30, TimeUnit.SECONDS)   // 讀取超時(shí)30秒
            .writeTimeout(30, TimeUnit.SECONDS)  // 寫(xiě)入超時(shí)30秒
            .addInterceptor(new LoggingInterceptor())
            .addInterceptor(new AuthInterceptor("initial-token"))
            .build();

    public static void main(String[] args) {
        // 1. 用戶(hù)登錄，獲取token
        String loginToken = loginUser("admin", "password123");

        if (loginToken == null) {
            System.err.println("Login failed!");
            return;
        }

        // 2. 使用獲取到的token，查詢(xún)用戶(hù)信息（此時(shí)AuthInterceptor會(huì)自動(dòng)添加token）
        getUserInfo(loginToken);
    }

    private static String loginUser(String username, String password) {
        RequestBody formBody = new FormBody.Builder()
                .add("username", username)
                .add("password", password)
                .build();

        Request request = new Request.Builder()
                .url("https://api.example.com/login")
                .post(formBody)
                .build();

        try (Response response = client.newCall(request).execute()) {
            if (!response.isSuccessful()) {
                System.err.println("Login failed: " + response.code());
                return null;
            }

            // 假設(shè)響應(yīng)體包含一個(gè)名為"token"的JSON字段，這里簡(jiǎn)化處理，僅返回字符串形式的token
            // 實(shí)際項(xiàng)目中應(yīng)使用JSON解析庫(kù)（如Jackson）來(lái)解析響應(yīng)體。
            String responseBody = response.body().string();
            System.out.println("Login success, token: " + responseBody);
            return responseBody;
        } catch (IOException e) {
            e.printStackTrace();
            return null;
        }
    }

    private static void getUserInfo(String token) {
        // 由于我們已經(jīng)在client中添加了AuthInterceptor，所以這里無(wú)需再手動(dòng)添加token
        Request request = new Request.Builder()
                .url("https://api.example.com/user/profile")
                .get() // GET請(qǐng)求獲取信息
                .build();

        // 使用異步請(qǐng)求，避免阻塞主線程
        client.newCall(request).enqueue(new Callback() {
            @Override
            public void onFailure(Call call, IOException e) {
                System.err.println("Failed to fetch user info: " + e.getMessage());
            }

            @Override
            public void onResponse(Call call, Response response) throws IOException {
                if (!response.isSuccessful()) {
                    System.err.println("Unexpected code: " + response.code());
                    return;
                }

                String responseBody = response.body().string();
                System.out.println("User Info: " + responseBody);
                response.close();
            }
        });

        // 主線程繼續(xù)執(zhí)行，不等待異步請(qǐng)求完成。
        System.out.println("Fetching user info... (async)");
    }
}