Java封装OkHttp3工具类，适用于Java后端开发者。
说实在话，用过挺多网络请求工具，有过java原生的，HttpClient3和4，但是个人感觉用了OkHttp3之后，之前的那些完全不想再用了。
怎么说呢，代码轻便，使用起来很很很灵活，响应快，比起HttpClient好用许多。当然，这些是我个人观点，不喜勿喷。
准备工作
Maven项目在pom文件中引入jar包
<dependency> <groupId>com.squareup.okhttp3</groupId> <artifactId>okhttp</artifactId> <version>3.10.0</version> </dependency> <dependency> <groupId>com.alibaba</groupId> <artifactId>fastjson</artifactId> <version>1.2.60</version> </dependency>
引入json是因为工具类中有些地方用到了，现在通信都流行使用json传输，也少不了要这个jar包
工具类代码
import com.alibaba.fastjson.JSON; import okhttp3.*; import javax.net.ssl.SSLContext; import javax.net.ssl.SSLSocketFactory; import javax.net.ssl.TrustManager; import javax.net.ssl.X509TrustManager; import java.io.IOException; import java.net.URLEncoder; import java.security.SecureRandom; import java.security.cert.X509Certificate; import java.util.LinkedHashMap; import java.util.Map; import java.util.concurrent.Semaphore; import java.util.concurrent.TimeUnit; public class OkHttpUtils { private static volatile OkHttpClient okHttpClient = null; private static volatile Semaphore semaphore = null; private Map<String, String> headerMap; private Map<String, String> paramMap; private String url; private Request.Builder request; /** * 初始化okHttpClient，并且允许https访问 */ private OkHttpUtils() { if (okHttpClient == null) { synchronized (OkHttpUtils.class) { if (okHttpClient == null) { TrustManager[] trustManagers = buildTrustManagers(); okHttpClient = new OkHttpClient.Builder() .connectTimeout(15, TimeUnit.SECONDS) .writeTimeout(20, TimeUnit.SECONDS) .readTimeout(20, TimeUnit.SECONDS) .sslSocketFactory(createSSLSocketFactory(trustManagers), (X509TrustManager) trustManagers[0]) .hostnameVerifier((hostName, session) -> true) .retryOnConnectionFailure(true) .build(); addHeader("User-Agent", "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/63.0.3239.132 Safari/537.36"); } } } } /** * 用于异步请求时，控制访问线程数，返回结果 * * @return */ private static Semaphore getSemaphoreInstance() { //只能1个线程同时访问 synchronized (OkHttpUtils.class) { if (semaphore == null) { semaphore = new Semaphore(0); } } return semaphore; } /** * 创建OkHttpUtils * * @return */ public static OkHttpUtils builder() { return new OkHttpUtils(); } /** * 添加url * * @param url * @return */ public OkHttpUtils url(String url) { this.url = url; return this; } /** * 添加参数 * * @param key 参数名 * @param value 参数值 * @return */ public OkHttpUtils addParam(String key, String value) { if (paramMap == null) { paramMap = new LinkedHashMap<>(16); } paramMap.put(key, value); return this; } /** * 添加请求头 * * @param key 参数名 * @param value 参数值 * @return */ public OkHttpUtils addHeader(String key, String value) { if (headerMap == null) { headerMap = new LinkedHashMap<>(16); } headerMap.put(key, value); return this; } /** * 初始化get方法 * * @return */ public OkHttpUtils get() { request = new Request.Builder().get(); StringBuilder urlBuilder = new StringBuilder(url); if (paramMap != null) { urlBuilder.append("?"); try { for (Map.Entry<String, String> entry : paramMap.entrySet()) { urlBuilder.append(URLEncoder.encode(entry.getKey(), "utf-8")). append("="). append(URLEncoder.encode(entry.getValue(), "utf-8")). append("&"); } } catch (Exception e) { e.printStackTrace(); } urlBuilder.deleteCharAt(urlBuilder.length() - 1); } request.url(urlBuilder.toString()); return this; } /** * 初始化post方法 * * @param isJsonPost true等于json的方式提交数据，类似postman里post方法的raw * false等于普通的表单提交 * @return */ public OkHttpUtils post(boolean isJsonPost) { RequestBody requestBody; if (isJsonPost) { String json = ""; if (paramMap != null) { json = JSON.toJSONString(paramMap); } requestBody = RequestBody.create(MediaType.parse("application/json; charset=utf-8"), json); } else { FormBody.Builder formBody = new FormBody.Builder(); if (paramMap != null) { paramMap.forEach(formBody::add); } requestBody = formBody.build(); } request = new Request.Builder().post(requestBody).url(url); return this; } /** * 同步请求 * * @return */ public String sync() { setHeader(request); try { Response response = okHttpClient.newCall(request.build()).execute(); assert response.body() != null; return response.body().string(); } catch (IOException e) { e.printStackTrace(); return "请求失败：" + e.getMessage(); } } /** * 异步请求，有返回值 */ public String async() { StringBuilder buffer = new StringBuilder(""); setHeader(request); okHttpClient.newCall(request.build()).enqueue(new Callback() { @Override public void onFailure(Call call, IOException e) { buffer.append("请求出错：").append(e.getMessage()); } @Override public void onResponse(Call call, Response response) throws IOException { assert response.body() != null; buffer.append(response.body().string()); getSemaphoreInstance().release(); } }); try { getSemaphoreInstance().acquire(); } catch (InterruptedException e) { e.printStackTrace(); } return buffer.toString(); } /** * 异步请求，带有接口回调 * * @param callBack */ public void async(ICallBack callBack) { setHeader(request); okHttpClient.newCall(request.build()).enqueue(new Callback() { @Override public void onFailure(Call call, IOException e) { callBack.onFailure(call, e.getMessage()); } @Override public void onResponse(Call call, Response response) throws IOException { assert response.body() != null; callBack.onSuccessful(call, response.body().string()); } }); } /** * 为request添加请求头 * * @param request */ private void setHeader(Request.Builder request) { if (headerMap != null) { try { for (Map.Entry<String, String> entry : headerMap.entrySet()) { request.addHeader(entry.getKey(), entry.getValue()); } } catch (Exception e) { e.printStackTrace(); } } } /** * 生成安全套接字工厂，用于https请求的证书跳过 * * @return */ private static SSLSocketFactory createSSLSocketFactory(TrustManager[] trustAllCerts) { SSLSocketFactory ssfFactory = null; try { SSLContext sc = SSLContext.getInstance("SSL"); sc.init(null, trustAllCerts, new SecureRandom()); ssfFactory = sc.getSocketFactory(); } catch (Exception e) { e.printStackTrace(); } return ssfFactory; } private static TrustManager[] buildTrustManagers() { return new TrustManager[]{ new X509TrustManager() { @Override public void checkClientTrusted(X509Certificate[] chain, String authType) { } @Override public void checkServerTrusted(X509Certificate[] chain, String authType) { } @Override public X509Certificate[] getAcceptedIssuers() { return new X509Certificate[]{}; } } }; } /** * 自定义一个接口回调 */ public interface ICallBack { void onSuccessful(Call call, String data); void onFailure(Call call, String errorMsg); } }
使用教程
public static void main(String[] args) { // get请求，方法顺序按照这种方式，切记选择post/get一定要放在倒数第二，同步或者异步倒数第一，才会正确执行 OkHttpUtils.builder().url("请求地址，http/https都可以") // 有参数的话添加参数，可多个 .addParam("参数名", "参数值") .addParam("参数名", "参数值") // 也可以添加多个 .addHeader("Content-Type", "application/json; charset=utf-8") .get() // 可选择是同步请求还是异步请求 //.async(); .sync(); // post请求，分为两种，一种是普通表单提交，一种是json提交 OkHttpUtils.builder().url("请求地址，http/https都可以") // 有参数的话添加参数，可多个 .addParam("参数名", "参数值") .addParam("参数名", "参数值") // 也可以添加多个 .addHeader("Content-Type", "application/json; charset=utf-8") // 如果是true的话，会类似于postman中post提交方式的raw，用json的方式提交，不是表单 // 如果是false的话传统的表单提交 .post(true) .sync(); // 选择异步有两个方法，一个是带回调接口，一个是直接返回结果 OkHttpUtils.builder().url("") .post(false) .async(); OkHttpUtils.builder().url("").post(false).async(new OkHttpUtils.ICallBack() { @Override public void onSuccessful(Call call, String data) { // 请求成功后的处理 } @Override public void onFailure(Call call, String errorMsg) { // 请求失败后的处理 } }); }
结语
封装的明明白白，使用的简简单单，简单的几下就能做请求，用建造者模式是真的舒服。
原文链接：https://blog.csdn.net/m0_37701381/article/details/103386345
