Java中的OkHttp怎么使用

今天小编给大家分享一下Java中的OkHttp怎么使用的相关知识点，内容详细，逻辑清晰，相信大部分人都还太了解这方面的知识，所以分享这篇文章给大家参考一下，希望大家阅读完这篇文章后有所收获，下面我们一起来了解一下吧。

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：

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

连接池减少请求延时

透明的GZIP压缩减少响应数据的大小

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

 <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

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;        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");                }            }        }    }        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;    }        public static OkHttpUtils builder() {        return new OkHttpUtils();    }        public OkHttpUtils url(String url) {        this.url = url;        return this;    }        public OkHttpUtils addParam(String key, String value) {        if (paramMap == null) {            paramMap = new LinkedHashMap<>(16);        }        paramMap.put(key, value);        return this;    }        public OkHttpUtils addHeader(String key, String value) {        if (headerMap == null) {            headerMap = new LinkedHashMap<>(16);        }        headerMap.put(key, value);        return this;    }        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;    }        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;    }        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();        }    }        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();    }        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());            }        });    }        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();            }        }    }        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[]{};                    }                }        };    }        public interface ICallBack {        void onSuccessful(Call call, String data);        void onFailure(Call call, String errorMsg);    }}

使用案例

发送get请求

        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

        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

//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

       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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