HttpUtils工具类（三）OKHttpClient使用详细教程

OkHttpClient 是一个由 Square 公司开发的 HTTP 客户端库，用于在 Android 和 Java 应用中进行网络请求。它支持同步和异步请求、连接池、超时设置、拦截器等功能，适合用于高性能网络请求，特别是在需要处理复杂的网络操作时。

一、OKHttpClient介绍

主要特点

同步和异步请求：
- 同步请求会在当前线程等待响应，适合不需要并发的简单请求。
- 异步请求会将网络操作交由后台线程处理，不会阻塞主线程，适合需要并发处理或在 Android 等环境中使用。
连接池： OkHttp 默认会使用连接池来复用 HTTP 连接，从而提高性能，减少连接的建立和关闭的开销。
拦截器 (Interceptor)：拦截器允许在请求和响应时进行操作，例如可以在请求发送前添加认证信息，或在响应到达后进行日志记录。
自动处理 HTTP/2 和 SPDY： OkHttp 默认支持 HTTP/2 协议，可以提升多路复用性能，使多个请求共享一个 TCP 连接。
缓存机制： OkHttp 提供了默认的缓存机制，可以根据 HTTP 响应头自动缓存请求结果，减少重复网络请求。
超时控制：可以对连接、读取和写入操作分别设置超时，避免长时间无响应的请求卡住应用。

二、在实际项目中的应用

（1）引入maven配置

<!-- ok的Http连接池 -->    
<dependency><groupId>com.squareup.okhttp3</groupId><artifactId>okhttp</artifactId><version>4.9.3</version>
</dependency>

（2）自定义HttpUtils工具类

import com.alibaba.fastjson.JSONObject;
import com.yan.project.httpUtils.okHttp2.HttpRequestBody;
import lombok.extern.slf4j.Slf4j;
import okhttp3.*;import java.io.Closeable;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.util.Map;
import java.util.Objects;
import java.util.Set;
import java.util.concurrent.TimeUnit;@Slf4j
public class OkHttpUtils {private OkHttpUtils() {throw new IllegalArgumentException("Utility class");}private static final String MIME_JSON = "application/json; charset=utf-8";private static OkHttpClient httpClient = new OkHttpClient.Builder().connectTimeout(3, TimeUnit.SECONDS).writeTimeout(5, TimeUnit.SECONDS).readTimeout(5, TimeUnit.SECONDS).addInterceptor((Interceptor.Chain chain) -> {Request req = chain.request();try {Response res = chain.proceed(req);return res;} catch (Exception ex) {throw ex;}}).build();// GET-无参public static String getJson(String url) throws IOException {return basicGet(url, null);}// GET-有参public static String get(String url, Map<String, Object> paramMap) throws Exception {StringBuilder sb = new StringBuilder(url);if (paramMap != null && !paramMap.isEmpty()) {Set<String> keySet = paramMap.keySet();for (String key : keySet) {sb.append(sb.toString().contains("?") ? "&" : "?");sb.append(key).append("=").append(paramMap.get(key));}url = sb.toString();}return basicGet(url, null);}// GET-有参、有请求头public static String getWithHeades(String url, Map<String, Object> paramMap, Map<String, String> headers) throws Exception {StringBuilder sb = new StringBuilder(url);if (paramMap != null && !paramMap.isEmpty()) {Set<String> keySet = paramMap.keySet();for (String key : keySet) {sb.append(sb.toString().contains("?") ? "&" : "?");sb.append(key).append("=").append(paramMap.get(key));}url = sb.toString();}return basicGet(url, headers);}// GET-jsonpublic static String getJsonWithHeader(String url, Map<String, String> headerMap) throws IOException {Request.Builder request = new Request.Builder().url(url).get().header("Accept", MIME_JSON);if (headerMap != null) {headerMap.forEach(request::header);}try (Response response = httpClient.newCall(request.build()).execute()) {log.info("response_code:{}, response_body:{}", response.code(), response.body().string());return response.body().string();}}// POST-json传参public static String postJsonWithHeader(String url, Object reqBody, Map<String, String> headers) throws IOException {Request.Builder request = new Request.Builder().url(url).header("Accept", MIME_JSON).post(FormBody.create(MediaType.parse(MIME_JSON), JSONObject.toJSONString(reqBody)));// 遍历并添加 headerif (headers != null) {headers.forEach(request::header);}try (Response response = httpClient.newCall(request.build()).execute()) {log.info("response_code:{}, response_body:{}", response.code(), response.body().string());return response.body().string();}}// POST-param传参public static String postParamWithHeader(String url, Map<String, Object> paramMap, Map<String, String> headers) throws IOException {FormBody.Builder formBody = new FormBody.Builder();if (Objects.nonNull(paramMap)) {paramMap.forEach((k, v) -> formBody.add(k, (String) v));}Request.Builder request = new Request.Builder().url(url).header("Accept", MIME_JSON).post(formBody.build());// 遍历并添加 headerif (headers != null) {headers.forEach(request::header);}try (Response response = httpClient.newCall(request.build()).execute()) {log.info("response_code:{}, response_body:{}", response.code(), response.body().string());return response.body().string();}}public static final String octet_stream_str = "application/octet-stream";public static final MediaType octet_stream = MediaType.parse(octet_stream_str);public static void putStream(String url, InputStream inputStream, long contentLength) {Response response;try {RequestBody requestBody2 = new HttpRequestBody(inputStream, contentLength);Request request = new Request.Builder().url(url).addHeader("Content-Type", octet_stream_str).put(requestBody2).build();response = httpClient.newCall(request).execute();String result = response.body().string();if (response.code() != 200) {throw new Exception("Saturn SDK stream upload failed, url:" + url + "response.code():" + response.code() + ", msg:" + result);}} catch (Exception e) {e.printStackTrace();} finally {closeQuietly(inputStream);}}public static String putFile(String url, File file) throws Exception {RequestBody requestBody = RequestBody.create(octet_stream, file);Request request = new Request.Builder().url(url).addHeader("Content-Type", octet_stream_str).put(requestBody).build();Response response = httpClient.newCall(request).execute();String result = response.body().string();int code = response.code();log.info("putFile end, url:{}, response.code:{}, result:{}", url, code, result);if (code != 200) {throw new Exception("putFile failed, response.code():" + code + ", result:" + result);}return result;}private static String basicGet(String url, Map<String, String> headers) throws IOException {Request.Builder builder = new Request.Builder().url(url).get();// 遍历并添加 headerif (headers != null) {headers.forEach(builder::header);}try (Response response = httpClient.newCall(builder.build()).execute()) {return response.body().string();}}private static String basicDelete(String url, Headers headers) throws IOException {Request.Builder builder = new Request.Builder().url(url).delete();if (headers != null) {builder.headers(headers);}try (Response response = httpClient.newCall(builder.build()).execute()) {return response.body().string();}}public static void closeQuietly(Closeable is) {if (is != null) {try {is.close();} catch (Exception ex) {log.error("Resources encounter an exception when closing，ex：{}", ex.getMessage());}}}
}

这个 OkHttpUtils 类封装了 OkHttpClient 来进行 HTTP 请求，支持 GET、POST、PUT 等常见的 HTTP 方法，并提供了对参数、请求头、文件上传等功能的支持。以下是它的主要功能和使用方法的解释：

OkHttpClient 实例

使用 OkHttpClient.Builder() 创建，设置了超时时间（连接超时 3 秒，读写超时 5 秒），并添加了拦截器。

静态方法

getJson, get, getWithHeades, getJsonWithHeader：用于 GET 请求，支持无参、有参数和请求头的场景。

postJsonWithHeader, postParamWithHeader：用于 POST 请求，支持 JSON 数据或表单数据传递。

putStream, putFile：用于 PUT 请求，支持流和文件上传。

basicGet, basicDelete：内部通用方法，分别处理 GET 和 DELETE 请求。