okhttp使用指南

kotlin 复制代码

// Gradle (build.gradle.kts)
implementation("com.squareup.okhttp3:okhttp:4.11.0")
implementation("com.squareup.okhttp3:logging-interceptor:4.11.0")

kotlin 复制代码

object HttpClient {
    val client: OkHttpClient by lazy {
        OkHttpClient.Builder()
            .connectTimeout(10, TimeUnit.SECONDS)
            .readTimeout(30, TimeUnit.SECONDS)
            .writeTimeout(30, TimeUnit.SECONDS)
            .addInterceptor(LoggingInterceptor())
            .addInterceptor(AuthInterceptor())
            .build()
    }
}

kotlin 复制代码

// 同步 GET
fun getUser(userId: String): String? {
    val request = Request.Builder()
        .url("https://api.example.com/users/$userId")
        .build()
    
    return try {
        HttpClient.client.newCall(request).execute().use { response ->
            if (response.isSuccessful) {
                response.body?.string()
            } else {
                throw Exception("HTTP ${response.code}: ${response.message}")
            }
        }
    } catch (e: Exception) {
        println("请求失败: ${e.message}")
        null
    }
}

// 异步 GET
fun getUserAsync(userId: String, callback: (String?) -> Unit) {
    val request = Request.Builder()
        .url("https://api.example.com/users/$userId")
        .build()
    
    HttpClient.client.newCall(request).enqueue(object : Callback {
        override fun onFailure(call: Call, e: IOException) {
            callback(null)
        }
        
        override fun onResponse(call: Call, response: Response) {
            response.use {
                callback(if (it.isSuccessful) it.body?.string() else null)
            }
        }
    })
}

kotlin 复制代码

fun createUser(userData: String): String? {
    val requestBody = userData.toRequestBody("application/json".toMediaType())
    
    val request = Request.Builder()
        .url("https://api.example.com/users")
        .post(requestBody)
        .build()
    
    return HttpClient.client.newCall(request).execute().use { response ->
        if (response.isSuccessful) {
            response.body?.string()
        } else {
            throw Exception("创建失败: ${response.code}")
        }
    }
}

kotlin 复制代码

fun login(username: String, password: String): String? {
    val formBody = FormBody.Builder()
        .add("username", username)
        .add("password", password)
        .build()
    
    val request = Request.Builder()
        .url("https://api.example.com/login")
        .post(formBody)
        .build()
    
    return HttpClient.client.newCall(request).execute().use { response ->
        response.body?.string()
    }
}

kotlin 复制代码

fun uploadFile(file: File, description: String): String? {
    val requestBody = MultipartBody.Builder()
        .setType(MultipartBody.FORM)
        .addFormDataPart("description", description)
        .addFormDataPart("file", file.name, 
            file.asRequestBody("application/octet-stream".toMediaType()))
        .build()
    
    val request = Request.Builder()
        .url("https://api.example.com/upload")
        .post(requestBody)
        .build()
    
    return HttpClient.client.newCall(request).execute().use { response ->
        response.body?.string()
    }
}

kotlin 复制代码

fun downloadFile(url: String, outputFile: File): Boolean {
    val request = Request.Builder().url(url).build()
    
    return try {
        HttpClient.client.newCall(request).execute().use { response ->
            if (response.isSuccessful) {
                response.body?.byteStream()?.use { inputStream ->
                    outputFile.outputStream().use { outputStream ->
                        inputStream.copyTo(outputStream)
                    }
                }
                true
            } else {
                false
            }
        }
    } catch (e: Exception) {
        false
    }
}

// 带进度的下载
fun downloadWithProgress(url: String, outputFile: File, 
                        onProgress: (progress: Int) -> Unit): Boolean {
    val request = Request.Builder().url(url).build()
    
    return try {
        HttpClient.client.newCall(request).execute().use { response ->
            if (response.isSuccessful) {
                val body = response.body ?: return false
                val contentLength = body.contentLength()
                
                body.byteStream().use { inputStream ->
                    outputFile.outputStream().use { outputStream ->
                        val buffer = ByteArray(8192)
                        var downloaded = 0L
                        var bytesRead: Int
                        
                        while (inputStream.read(buffer).also { bytesRead = it } != -1) {
                            outputStream.write(buffer, 0, bytesRead)
                            downloaded += bytesRead
                            
                            if (contentLength > 0) {
                                val progress = (downloaded * 100 / contentLength).toInt()
                                onProgress(progress)
                            }
                        }
                    }
                }
                true
            } else {
                false
            }
        }
    } catch (e: Exception) {
        false
    }
}

kotlin 复制代码

class LoggingInterceptor : Interceptor {
    override fun intercept(chain: Interceptor.Chain): Response {
        val request = chain.request()
        val startTime = System.nanoTime()
        
        println("发送请求: ${request.method} ${request.url}")
        
        val response = chain.proceed(request)
        val endTime = System.nanoTime()
        
        println("收到响应: ${response.code} in ${(endTime - startTime) / 1e6}ms")
        
        return response
    }
}

kotlin 复制代码

class AuthInterceptor(private val token: String) : Interceptor {
    override fun intercept(chain: Interceptor.Chain): Response {
        val originalRequest = chain.request()
        
        val authenticatedRequest = originalRequest.newBuilder()
            .header("Authorization", "Bearer $token")
            .build()
        
        return chain.proceed(authenticatedRequest)
    }
}

kotlin 复制代码

class RetryInterceptor(private val maxRetries: Int = 3) : Interceptor {
    override fun intercept(chain: Interceptor.Chain): Response {
        var request = chain.request()
        var response = chain.proceed(request)
        var retryCount = 0
        
        while (!response.isSuccessful && retryCount < maxRetries) {
            retryCount++
            println("重试第 $retryCount 次: ${request.url}")
            
            response.close()
            response = chain.proceed(request)
        }
        
        return response
    }
}

kotlin 复制代码

class CacheInterceptor(private val maxAge: Int = 60) : Interceptor {
    override fun intercept(chain: Interceptor.Chain): Response {
        val request = chain.request()
        val response = chain.proceed(request)
        
        return response.newBuilder()
            .header("Cache-Control", "public, max-age=$maxAge")
            .build()
    }
}

kotlin 复制代码

val cacheSize = 10 * 1024 * 1024L // 10MB
val cache = Cache(File(context.cacheDir, "http-cache"), cacheSize)

val clientWithCache = OkHttpClient.Builder()
    .cache(cache)
    .addNetworkInterceptor(CacheInterceptor())
    .build()

kotlin 复制代码

// 信任所有证书（仅用于开发环境）
fun createUnsafeClient(): OkHttpClient {
    val trustAllCerts = arrayOf<TrustManager>(object : X509TrustManager {
        override fun checkClientTrusted(chain: Array<X509Certificate>, authType: String) {}
        override fun checkServerTrusted(chain: Array<X509Certificate>, authType: String) {}
        override fun getAcceptedIssuers(): Array<X509Certificate> = arrayOf()
    })
    
    val sslContext = SSLContext.getInstance("SSL")
    sslContext.init(null, trustAllCerts, SecureRandom())
    
    return OkHttpClient.Builder()
        .sslSocketFactory(sslContext.socketFactory, trustAllCerts[0] as X509TrustManager)
        .hostnameVerifier { _, _ -> true }
        .build()
}

// 证书锁定（生产环境推荐）
val clientWithPinning = OkHttpClient.Builder()
    .certificatePinner(
        CertificatePinner.Builder()
            .add("api.example.com", "sha256/AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA=")
            .build()
    )
    .build()

kotlin 复制代码

class HttpUtil private constructor() {
    companion object {
        private val client = OkHttpClient.Builder()
            .connectTimeout(10, TimeUnit.SECONDS)
            .readTimeout(30, TimeUnit.SECONDS)
            .addInterceptor(HttpLoggingInterceptor().apply { 
                level = HttpLoggingInterceptor.Level.BODY 
            })
            .build()
        
        // GET 请求
        fun get(url: String, headers: Map<String, String> = emptyMap()): String? {
            val requestBuilder = Request.Builder().url(url)
            headers.forEach { (key, value) -> 
                requestBuilder.addHeader(key, value) 
            }
            
            return try {
                client.newCall(requestBuilder.build()).execute().use { response ->
                    if (response.isSuccessful) response.body?.string() else null
                }
            } catch (e: Exception) {
                null
            }
        }
        
        // POST JSON
        fun postJson(url: String, json: String, headers: Map<String, String> = emptyMap()): String? {
            val requestBody = json.toRequestBody("application/json".toMediaType())
            val requestBuilder = Request.Builder().url(url).post(requestBody)
            headers.forEach { (key, value) -> 
                requestBuilder.addHeader(key, value) 
            }
            
            return try {
                client.newCall(requestBuilder.build()).execute().use { response ->
                    if (response.isSuccessful) response.body?.string() else null
                }
            } catch (e: Exception) {
                null
            }
        }
        
        // 异步请求
        fun getAsync(url: String, callback: (String?) -> Unit) {
            val request = Request.Builder().url(url).build()
            client.newCall(request).enqueue(object : Callback {
                override fun onFailure(call: Call, e: IOException) {
                    callback(null)
                }
                override fun onResponse(call: Call, response: Response) {
                    response.use { callback(if (it.isSuccessful) it.body?.string() else null) }
                }
            })
        }
    }
}

kotlin 复制代码

data class ApiResponse<T>(
    val code: Int,
    val message: String,
    val data: T?
) {
    val isSuccess: Boolean get() = code == 200
}

// 使用示例
inline fun <reified T> parseResponse(json: String): ApiResponse<T>? {
    return try {
        Gson().fromJson(json, object : TypeToken<ApiResponse<T>>() {}.type)
    } catch (e: Exception) {
        null
    }
}

kotlin 复制代码

class UserService {
    private val baseUrl = "https://api.example.com"
    
    fun login(email: String, password: String): ApiResponse<String>? {
        val loginData = mapOf("email" to email, "password" to password)
        val json = Gson().toJson(loginData)
        
        val response = HttpUtil.postJson("$baseUrl/login", json)
        return response?.let { parseResponse<String>(it) }
    }
    
    fun getUserProfile(token: String): ApiResponse<User>? {
        val headers = mapOf("Authorization" to "Bearer $token")
        val response = HttpUtil.get("$baseUrl/profile", headers)
        return response?.let { parseResponse<User>(it) }
    }
    
    fun uploadAvatar(token: String, avatarFile: File, callback: (Boolean) -> Unit) {
        val requestBody = MultipartBody.Builder()
            .setType(MultipartBody.FORM)
            .addFormDataPart("avatar", avatarFile.name,
                avatarFile.asRequestBody("image/*".toMediaType()))
            .build()
        
        val request = Request.Builder()
            .url("$baseUrl/upload-avatar")
            .addHeader("Authorization", "Bearer $token")
            .post(requestBody)
            .build()
        
        HttpClient.client.newCall(request).enqueue(object : Callback {
            override fun onFailure(call: Call, e: IOException) {
                callback(false)
            }
            
            override fun onResponse(call: Call, response: Response) {
                callback(response.isSuccessful)
            }
        })
    }
}

kotlin 复制代码

// 详细日志记录
val loggingInterceptor = HttpLoggingInterceptor().apply {
    level = HttpLoggingInterceptor.Level.BODY
}

// 网络状态监控
class NetworkStatusInterceptor : Interceptor {
    override fun intercept(chain: Interceptor.Chain): Response {
        val request = chain.request()
        println("请求: ${request.method} ${request.url}")
        println("请求头: ${request.headers}")
        
        val startTime = System.currentTimeMillis()
        val response = chain.proceed(request)
        val endTime = System.currentTimeMillis()
        
        println("响应: ${response.code} (${endTime - startTime}ms)")
        println("响应头: ${response.headers}")
        
        return response
    }
}

kotlin 复制代码

class MockInterceptor : Interceptor {
    override fun intercept(chain: Interceptor.Chain): Response {
        val request = chain.request()
        
        // 根据 URL 返回模拟数据
        return when {
            request.url.toString().contains("/users/123") -> {
                val mockResponse = """{"id":123,"name":"测试用户"}"""
                Response.Builder()
                    .request(request)
                    .protocol(Protocol.HTTP_1_1)
                    .code(200)
                    .message("OK")
                    .body(mockResponse.toResponseBody("application/json".toMediaType()))
                    .build()
            }
            else -> chain.proceed(request)
        }
    }
}

okhttp使用指南

1. 基础配置

依赖添加

单例客户端配置

2. 基本请求方法

GET 请求

POST JSON 请求

POST 表单请求

3. 文件操作

文件上传

文件下载

4. 实用拦截器

日志拦截器

认证拦截器

重试拦截器

缓存拦截器

5. 高级配置

缓存设置

HTTPS 配置

6. 工具类封装

HTTP 工具类

API 响应包装类

7. 实际使用示例

用户服务示例

8. 调试和测试

调试技巧

Mock 数据