什么是OKHttp
一般在Java平台上，我们会使用Apache HttpClient作为Http客户端，用于发送 HTTP 请求，并对响应进行处理。比如可以使用http客户端与第三方服务(如SSO服务)进行集成，当然还可以爬取网上的数据等。OKHttp与HttpClient类似，也是一个Http客户端，提供了对 HTTP/2 和 SPDY 的支持，并提供了连接池，GZIP 压缩和 HTTP 响应缓存功能；
OkHttp是目前非常火的网络库，它有以下特性：
1.支持HTTP/2，允许所有同一个主机地址的请求共享同一个socket连接
2.连接池减少请求延时
3.透明的GZIP压缩减少响应数据的大小
4.缓存响应内容，避免一些完全重复的请求
OkHttp基本使用
- OkHttpClient：客户端对象
- Request：访问请求，Post请求中需要包含RequestBody
- RequestBody：请求数据，在Post请求中用到
- Response：即网络请求的响应结果
- MediaType：数据类型，用来表明数据是json，image，pdf等一系列格式
- client.newCall(request).execute()：同步的请求方法
- client.newCall(request).enqueue(Callback callBack)：异步的请求方法，但Callback是执行在子线程中的，因此不能在此进行UI更新操作
官网：http://square.github.io/okhttp/
添加依赖
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<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> |
OkHttp工具类
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package com.loginsimpl.utils;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 (限流的,同一时间只允许一个访问,其他等待) */ 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); }} |
使用案例
发送get请求
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String sync = OkHttpUtils.builder().url("http://localhost:9100/user/all") .addHeader("token", "xxxxxxx") .addParam("name", "xxx").addParam("pass", "xxx") .get() .sync();System.out.println(sync); |
发送Post请求
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String sync = OkHttpUtils.builder().url("http://localhost:9100/user/all") .addHeader("token", "xxxxxxx") .addParam("name", "xxx").addParam("pass", "xxx") .post(true) // true 为json提交方式 .sync();System.out.println(sync); |
发送异步请求
需要实现ICallBack接口
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//回调实现类public class AsyncHttpServiceImpl implements OkHttpUtils.ICallBack { @Override public void onSuccessful(Call call, String data) { //接口正常返回的内容 System.out.println("onSuccessful"+data); } @Override public void onFailure(Call call, String errorMsg) { //接口错误返回的内容 System.out.println("onFailure"+errorMsg); }} |
发送异步请求
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OkHttpUtils.builder().url("http://localhost:9100/user/all") .addHeader("token", "xxxxxxx") .addParam("name", "xxx").addParam("pass", "xxx") .post(true) .async(new AsyncHttpServiceImpl()); |
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原文链接：https://blog.csdn.net/weixin_45203607/article/details/124204137
