一、OKHttp框架介绍

OKHttp是Square出品的Http网络请求库，在Android中HTTP网络请求通信类有HttpURLConnection和HttpClient，但是在高版本中HttpClient已经被废弃，而Android4.4的源码中HttpURLConnection也已经替换成了OKHttp。

二、OKHttp导包

1、导包可以在自己项目Module的gradle文件中添加如下代码：

dependencies { compile fileTree(include: ['*.jar'], dir: 'libs') androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', { exclude group: 'com.android.support', module: 'support-annotations' }) compile 'com.android.support:appcompat-v7:25.2.0' testCompile 'junit:junit:4.12' compile 'com.squareup.okhttp3:okhttp:3.6.0'//引入这句话，然后执行同步操作 }

2、通过收索jar包引入

三、OKHttp实现HTTP Get同步请求步骤

1、获取Resquest对象

访问请求，Builder是辅助类

2、获取Response对象

获取call对象，调用该方法的execute方法

3、获取ResponseBody对象

通过body方法获取

4、从ResponseBody对象中获取服务器返回的数据

代码如下： public class OKHttpUtils { //保证只存在一个对象 private static final OkHttpClient client = new OkHttpClient(); /** * 获取Resquest * @param url * @return */ private static Request getRequest(String url) { Request request = new Request.Builder() .url(url) .build(); return request; } /** * 获取Response * * @param url * @return * @throws IOException */ private static Response getResponse(String url) throws IOException { Request request = getRequest(url); Response response = client.newCall(request).execute(); return response; } /** * 获取ResponseBody * * @param url * @return * @throws IOException */ private static ResponseBody getResonseBody(String url) throws IOException { Response response = getResponse(url); if (response.isSuccessful()) { return response.body(); } return null; } /** * get请求 返回字符串 * * @param url * @return * @throws IOException */ public static String getStringFromURL(String url) throws IOException { ResponseBody resonseBody = getResonseBody(url); if (resonseBody != null) { return resonseBody.string(); } return null; } /** * get请求 获取字节数组 * * @param url * @return * @throws IOException */ public static byte[] getByteFromURL(String url) throws IOException { ResponseBody responseBody = getResonseBody(url); if (responseBody != null) { byte[] bytes = responseBody.bytes(); return bytes; } return null; } /** * get请求 获取输入流 * * @param url * @return * @throws IOException */ public static InputStream getStreamFromURL(String url) throws IOException { ResponseBody resonseBody = getResonseBody(url); if (resonseBody != null) { return resonseBody.byteStream(); } return null; } } 注意： 以上方法在执行的时候是执行的同步网络请求，所以要放到子线程中执行，如下： new Thread(new Runnable() { @Override public void run() { try { String stringFromURL = OKHttpUtils.getStringFromURL(String.format(Constant.URL_LATEST, 1)); } catch (IOException e) { e.printStackTrace(); } } }).start();

四、OKHttp实现HTTP Get异步请求步骤

1、获取Request对象

2、将Request请求添加到请求队列

Call对象的enqueue方法是OKHttp提供的异步访问方法，而execute则是同步方法，enqueue方法底层调用getExecutorService开启子线程

3、实现回调方法

代码如下： /** * get 异步请求，在enqueue源码中调用线程池服务已经开启子线程 * @param url * @param callback * @throws IOException */ public static void getNetDataAsync(String url, Callback callback) throws IOException { //或Request Request request = getRequest(url); //将Request传入Call Call call = client.newCall(request); //执行Call的enqueue方法 call .enqueue(callback); } 数据回调： private void loadDataFromNet() { //异步调用get请求 try { OKHttpUtils.getNetDataAsync(String.format(Constant.URL_LATEST, 1), new Callback() { /** * 加载失败时调用 * * @param call * @param e */ @Override public void onFailure(Call call, IOException e) { //子线程 Log.e("--------onFailure>", Thread.currentThread().getId() + ""); } /** * 加载成功时调用 * * @param call * @param response * @throws IOException */ @Override public void onResponse(Call call, Response response) throws IOException { //子线程 Log.e("--------onResponse>", Thread.currentThread().getId() + ""); String string = response.body().string(); List<Map<String, String>> maps = jsonStringToList(string); runOnUiThread(new Runnable() { @Override public void run() { //在主线程中执行UI更改 } }); } }); } catch (IOException e) { e.printStackTrace(); } }

四、OKHttp实现Http POST请求 步骤

1、往FormBody对象中放置键值对数据（OKHttp3.0之前是FormEncodingBuilder）

2、获取RequestBody请求体对象

3、获取Request对象，将RequestBody放置到Request对象中

4、获取Response对象

5、获取ResponseBody对象

6、从ResponseBody对象中获取服务器端返回的数据

代码 /// // Post同步请求 /// /** * 构建Request 将url和RequestBody传入 * * @param url * @param requestBody * @return */ private static Request buildPostRequest(String url, RequestBody requestBody) { Request request = new Request.Builder().url(url).post(requestBody).build(); return request; } /** * 提交RequestBody * * @param url * @param requestBody * @return * @throws IOException */ private static String postRequestBody(String url, RequestBody requestBody) throws IOException { Request request = buildPostRequest(url, requestBody); Response response = client.newCall(request).execute(); if (response.isSuccessful()) { return response.body().string(); } return null; } /** * 构建buildRequestBody * * @param map * @return */ private static RequestBody buildRequestBody(Map<String, String> map) { FormBody.Builder builder = new FormBody.Builder(); for (Map.Entry<String, String> entry : map.entrySet()) { builder.add(entry.getKey(), entry.getValue()); } return builder.build(); } /** * 提交键值对 POST网络请求 * * @param url * @param map * @return * @throws IOException */ public static String postKeyValuePair(String url, Map<String, String> map) throws IOException { RequestBody requestBody = buildRequestBody(map); return postRequestBody(url, requestBody); } 以上是同步请求，和GET 一样需要放在子线程中执行

POST异步请求代码：

/** * 提交Post异步请求 * * @param url * @param map * @param callback */ private static void postRequestBodyAsync(String url, RequestBody requestBody, Callback callback) { Request request = buildPostRequest(url, requestBody); client.newCall(request).enqueue(callback); } public static void postKeyValuePairAsync(String url, Map<String, String> map, Callback callback) { RequestBody requestBody = buildRequestBody(map); postRequestBodyAsync(url,requestBody,callback); }

五、OKHttp高级用法介绍

Post同步上传文件

1、往MultipartBuilder对象中加入各请求块的 数据 2、构建RequestBody请求体对象（包含各个请求块） 3、获取Request对象（包含ReqBody） 4、获取Response对象 5、获取ResponseBody对象 6、从ResponseBody对象中获取服务器返回的数据 /** * 作用：post同步上传文件以及其它表单控件（也就是提交分块请求） * * @param urlString 网络地址 * @param map 提交给服务器的表单信息键值对 * @param files 提交的文件 * @param formFieldName 每个需要提交的文件对应的文件input的name值 * @return * @throws IOException */ public static String postUploadFiles(String urlString, Map<String, String> map, File[] files, String[] formFieldName) throws IOException { RequestBody requestBody = buildRequestBody(map, files, formFieldName); return postRequestBody(urlString, requestBody); } /** * 作用：生成提交分块请求时的RequestBody对象 * * @param map * @param files * @param formFieldName * @return */ private static RequestBody buildRequestBody(Map<String, String> map, File[] files, String[] formFieldName) { MultipartBuilder builder = new MultipartBuilder().type(MultipartBuilder.FORM); //第一部分提交：文件控件以外的其它input的数据 if (map != null) { for (Map.Entry<String, String> entry : map.entrySet()) { builder.addPart(Headers.of("Content-Disposition", "form-data;name=\"" + entry.getKey() + "\""), RequestBody.create(null, entry.getValue())); } } //第二部分：上传文件控件的数据 //往MultipartBuilder对象中添加file input控件的内容 if (files != null && formFieldName != null) { for (int i = 0; i < files.length; i++) { File file = files[i]; String fileName = file.getName(); RequestBody requestBody = RequestBody.create(MediaType.parse(getMimeType(fileName)), file); //添加file input块的数据 builder.addPart(Headers.of("Content-Disposition", "form-data; name=\"" + formFieldName[i] + "\"; filename=\"" + fileName + "\""), requestBody); } } return builder.build(); } /** * 获取文件MimeType * * @param filename * @return */ private static String getMimeType(String filename) { FileNameMap filenameMap = URLConnection.getFileNameMap(); String contentTypeFor = filenameMap.getContentTypeFor(filename); if (contentTypeFor == null) { contentTypeFor = "application/octet-stream"; } return contentTypeFor; } 子线程中使用 new Thread(new Runnable() { @Override public void run() { try { final String result = OkHttpUtils.postUploadFiles(URL_UPLOAD, map , files , formFieldName); runOnUiThread(new Runnable() { @Override public void run() { Toast.makeText(mContext , result , Toast.LENGTH_SHORT).show(); } }); } catch (IOException e) { e.printStackTrace(); Log.d(TAG, "---->e:" + e.toString()); } } }).start(); Post异步上传文件 /** * 作用：post异步网络请求，提交RequestBody对象 * * @param urlString * @param requestBody * @param callback */ private static void postRequestBodyAsync(String urlString, RequestBody requestBody, Callback callback) { Request request = buildPostRequest(urlString, requestBody); okHttpClient.newCall(request).enqueue(callback); } /** * 作用：post异步上传文件，提交分块请求 * * @param urlString 网络地址 * @param map 提交给服务器的表单信息键值对 * @param files 提交的文件 * @param formFieldName 每个需要提交的文件对应的文件input的name值 * @param callback 异步上传回调方法 * @throws IOException */ public static void postUploadFilesAsync(String urlString, Map<String, String> map, File[] files, String[] formFieldName, Callback callback) throws IOException { RequestBody requestBody = buildRequestBody(map, files, formFieldName); postRequestBodyAsync(urlString, requestBody, callback); }

上传操作

OkHttpUtils.postUploadFilesAsync(URL_UPLOAD, map, files, formFieldName, new Callback() { @Override public void onFailure(final Request request, IOException e) { Log.d(TAG, "---->e1:" + e.toString()); runOnUiThread(new Runnable() { @Override public void run() { Toast.makeText(mContext, "网络异常，加载失败！", Toast.LENGTH_SHORT).show(); } }); } @Override public void onResponse(final Response response) throws IOException { runOnUiThread(new Runnable() { @Override public void run() { if (response.isSuccessful()) { try { textView_result.setText(response.body().string()); Toast.makeText(mContext, response.body().string(), Toast.LENGTH_SHORT).show(); } catch (Exception ex) { } } } }); } }); 六、OKHttp性能优化

1、设置tag

设置tag的作用是为每次的请求设置一个标记，可以根据这个标记取消请求，tag可以为任何数据类型 设置tag Request.Builder builder = new Request.Builder(); builder.url(urlString); if (tag != null) { builder.tag(tag); } 取消请求 okHttpClient.cancel(tag);

2、在文件系统中开启响应缓存

设置缓存，把获取的内容缓存到手机本地指定的文件夹中，下次访问同样的Url时，会从本地获取上次服务器返回的内容，大大提高了加载响应的速度，提高用户体验 //开启响应缓存 okHttpClient.setCookieHandler(new CookieManager(null, CookiePolicy.ACCEPT_ORIGINAL_SERVER)); //设置缓存目录和大小 int cacheSize = 10 << 20; // 10 MiB Cache cache = new Cache(context.getCacheDir(), cacheSize); okHttpClient.setCache(cache); 3、指定合理超时 //设置连接超时 okHttpClient.setConnectTimeout(15, TimeUnit.SECONDS); //设置读取超时 okHttpClient.setReadTimeout(20, TimeUnit.SECONDS); //设置写入超时 okHttpClient.setWriteTimeout(20, TimeUnit.SECONDS);

4、使用Picasso和Retrofit时保持OKHttp单例

public static OkHttpClientUtils getOkHttpClientUtils(Context context) { if (okHttpUtils == null) { synchronized (OkHttpClientUtils.class) { if (okHttpUtils == null) { okHttpUtils = new OkHttpClientUtils(context); } } } return okHttpUtils; } public static OkHttpClient getOkHttpSingletonInstance() { if (okHttpClient == null) { synchronized (OkHttpClient.class) { if (okHttpClient == null) { okHttpClient = new OkHttpClient(); } } } return okHttpClient; }

OKHttp工具类

public class OkHttpClientUtils { private static OkHttpClientUtils okHttpUtils = null; private static OkHttpClient okHttpClient = null; private static Context context; private OkHttpClientUtils(Context context) { this.context = context; okHttpClient = getOkHttpSingletonInstance(); } public static OkHttpClientUtils getOkHttpClientUtils(Context context) { if (okHttpUtils == null) { synchronized (OkHttpClientUtils.class) { if (okHttpUtils == null) { okHttpUtils = new OkHttpClientUtils(context); } } } return okHttpUtils; } public static OkHttpClient getOkHttpSingletonInstance( ) { if (okHttpClient == null) { synchronized (OkHttpClient.Builder.class) { if (okHttpClient == null) { OkHttpClient.Builder builder = new OkHttpClient.Builder(); builder.cookieJar(new CookieJar() { private final HashMap<HttpUrl, List<Cookie>> cookieStore = new HashMap<>(); @Override public void saveFromResponse(HttpUrl url, List<Cookie> cookies) { cookieStore.put(url, cookies); } @Override public List<Cookie> loadForRequest(HttpUrl url) { List<Cookie> cookies = cookieStore.get(url); return cookies != null ? cookies : new ArrayList<Cookie>(); } }); //设置缓存目录和大小 int cacheSize = 10 << 20; // 10 MiB if (context!=null){ Cache cache = new Cache(context.getCacheDir(), cacheSize); builder.cache(cache); } //设置合理的超时 //设置连接超时 builder.connectTimeout(15, TimeUnit.SECONDS); //设置读取超时 builder.readTimeout(20, TimeUnit.SECONDS); //设置写入超时 builder.writeTimeout(20, TimeUnit.SECONDS); //以下验证不设置，那么默认就已经设置了验证 builder.hostnameVerifier(new HostnameVerifier() { @Override public boolean verify(String hostname, SSLSession session) { return true; } }); okHttpClient = builder.build(); } } } return okHttpClient; } /// // GET方式网络访问 /// /** * 基方法，返回Request对象 * * @param urlString * @param tag * @return */ private Request buildGetRequest(String urlString, Object tag) { Request.Builder builder = new Request.Builder(); builder.url(urlString); if (tag != null) { builder.tag(tag); } return builder.build(); } /** * 自定义方法，返回Response对象 * * @param urlString * @return * @throws IOException */ private Response buildResponse(String urlString, Object tag) throws IOException { Request request = buildGetRequest(urlString, tag); Response response = okHttpClient.newCall(request).execute(); return response; } //基础方法，返回ResponseBody对象 private ResponseBody buildResponseBody(String urlString, Object tag) throws IOException { Response response = buildResponse(urlString, tag); if (response.isSuccessful()) { return response.body(); } return null; } /** * 作用：实现网络访问文件，将获取到数据储存在文件流中 * * @param urlString ：访问网络的url地址 * @return InputStream */ public static InputStream getStreamFromURL(Context context, String urlString, Object tag) throws IOException { ResponseBody body = getOkHttpClientUtils(context).buildResponseBody(urlString, tag); if (body != null) { return body.byteStream(); } return null; } /** * 作用：实现网络访问文件，将获取到的数据存在字节数组中 * * @param urlString ：访问网络的url地址 * @return byte[] */ public static byte[] getBytesFromURL(Context context, String urlString, Object tag) throws IOException { ResponseBody body = getOkHttpClientUtils(context).buildResponseBody(urlString, tag); if (body != null) { return body.bytes(); } return null; } /** * 作用：实现网络访问文件，将获取到的数据存在字符串中 * * @param urlString ：访问网络的url地址 * @return String */ public static String getStringFromURL(Context context, String urlString, Object tag) throws IOException { ResponseBody body = getOkHttpClientUtils(context).buildResponseBody(urlString, tag); if (body != null) { return body.string(); } return null; } /// // POST方式访问网络 /// /** * 基方法，返回Request对象 * * @param urlString * @param tag * @return */ private Request buildPostRequest(String urlString, RequestBody requestBody, Object tag) { Request.Builder builder = new Request.Builder(); builder.url(urlString).post(requestBody); //builder.addHeader("Accept", "application/json; q=0.5"); if (tag != null) { builder.tag(tag); } return builder.build(); } /** * 作用：post提交数据，返回服务器端返回的字节数组 * * @param urlString ：访问网络的url地址 * @return byte[] */ private String postRequestBody(String urlString, RequestBody requestBody, Object tag) { Request request = buildPostRequest(urlString, requestBody, tag); try { Response response = okHttpClient.newCall(request).execute(); if (response.isSuccessful()) { return response.body().string(); } } catch (Exception e) { e.printStackTrace(); } return null; } /** * 作用：POST提交键值对，再返回相应的数据 * * @param urlString ：访问网络的url地址 * @param map ：访问url时，需要传递给服务器的键值对数据。 * @return String */ public static String postKeyValuePair(Context context, String urlString, Map<String, String> map, Object tag) { //往FormEncodingBuilder对象中放置键值对 FormBody.Builder formBuilder = new FormBody.Builder(); if (map != null && !map.isEmpty()) { for (Map.Entry<String, String> entry : map.entrySet()) { formBuilder.add(entry.getKey(), entry.getValue()); } } //生成请求体对象 RequestBody requestBody = formBuilder.build(); //将请求提放置到请求对象中 return getOkHttpClientUtils(context).postRequestBody(urlString, requestBody, tag); } /** * 作用：POST提交Json字符串，再返回相应的数据 * * @param urlString ：访问网络的url地址 * @param jsonString ：访问url时，需要传递给服务器的json字符串 * @return byte[] */ public static String postJsonString(Context context, String urlString, String jsonString, Object tag) { //定义mimetype对象 /*String MEDIA_TYPE_STREAM = "application/octet-stream;charset=utf-8"; String MEDIA_TYPE_STRING = "text/plain;charset=utf-8";*/ String MEDIA_TYPE_JSON = "application/json;charset=utf-8"; MediaType JSON = MediaType.parse(MEDIA_TYPE_JSON); RequestBody requestBody = RequestBody.create(JSON, jsonString); return getOkHttpClientUtils(context).postRequestBody(urlString, requestBody, tag); } /// // 异步网络访问 /// /** * 开启异步线程访问网络，通过回调方法实现数据加载 * 如果第二个参数为null，空callback， 则说明不在意返回结果 * * @param urlString * @param callback */ public static void getDataAsync(Context context, String urlString, Callback callback, Object tag) { Request request = getOkHttpClientUtils(context).buildGetRequest(urlString, tag); if (callback == null) { new Callback() { @Override public void onFailure(Call call, IOException e) { } @Override public void onResponse(Call call, Response response) throws IOException { } }; } getOkHttpSingletonInstance( ).newCall(request).enqueue(callback); } /** * 作用：post提交数据，返回服务器端返回的字节数组 * * @param urlString ：访问网络的url地址 */ private void postRequestBodyAsync(String urlString, RequestBody requestBody, Callback callback, Object tag) { Request request = buildPostRequest(urlString, requestBody, tag); if (callback == null) { new Callback() { @Override public void onFailure(Call call, IOException e) { } @Override public void onResponse(Call call, Response response) throws IOException { } }; } okHttpClient.newCall(request).enqueue(callback); } /** * 作用：POST提交键值对，再返回相应的数据 * * @param urlString ：访问网络的url地址 * @param map ：访问url时，需要传递给服务器的键值对数据。 */ public static void postKeyValuePairAsync(Context context, String urlString, Map<String, String> map, Callback callback, Object tag) { //往FormEncodingBuilder对象中放置键值对 FormBody.Builder formBuilder = new FormBody.Builder(); if (map != null && !map.isEmpty()) { for (Map.Entry<String, String> entry : map.entrySet()) { formBuilder.add(entry.getKey(), entry.getValue()); } } //生成请求体对象 RequestBody requestBody = formBuilder.build(); //将请求提放置到请求对象中 getOkHttpClientUtils(context).postRequestBodyAsync(urlString, requestBody, callback, tag); } /** * 作用：post异步上传文件，提交分块请求 * * @param urlString 网络地址 * @param map 提交给服务器的表单信息键值对 * @param files 提交的文件 * @param formFieldName 每个需要提交的文件对应的文件input的name值 * @param callback 异步上传回调方法 * @throws IOException */ public static void postUploadFilesAsync(Context context, String urlString, Map<String, String> map, File[] files, String[] formFieldName, Callback callback, Object tag) throws IOException { RequestBody requestBody = getOkHttpClientUtils(context).buildRequestBody(map, files, formFieldName); getOkHttpClientUtils(context).postRequestBodyAsync(urlString, requestBody, callback, tag); } /// // POST方式提交分块请求，实现文件上传 /// /** * 同步基于post的文件上传:上传多个文件以及携带key-value对：主方法 * * @param urlString * @param formFiledName * @param files * @param map * @param tag * @return String * @throws IOException */ public static String postUploadFiles(Context context, String urlString, Map<String, String> map, File[] files, String[] formFiledName, Object tag) throws IOException { RequestBody requestBody = getOkHttpClientUtils(context).buildRequestBody(map, files, formFiledName); return getOkHttpClientUtils(context).postRequestBody(urlString, requestBody, tag); } /** * 创建post上传附件的request对象 * Post方式提交分块请求——上传文件及其它表单数据 * * @param files * @param formFiledName * @param map * @return */ private RequestBody buildRequestBody(Map<String, String> map, File[] files, String[] formFiledName) { MultipartBody.Builder builder = new MultipartBody.Builder().setType(MultipartBody.FORM); //往MultipartBuilder对象中添加普通input控件的内容 if (map != null) { for (Map.Entry<String, String> entry : map.entrySet()) { //添加普通input块的数据 builder.addPart(Headers.of("Content-Disposition", "form-data; name=\"" + entry.getKey() + "\""), RequestBody.create(null, entry.getValue())); } } //往MultipartBuilder对象中添加file input控件的内容 if (files != null && formFiledName != null) { for (int i = 0; i < files.length; i++) { File file = files[i]; String fileName = file.getName(); RequestBody requestBody = RequestBody.create(MediaType.parse("multipart/form-data"), file); //添加file input块的数据 builder.addPart(Headers.of("Content-Disposition", "form-data; name=\"" + formFiledName[i] + "\"; filename=\"" + fileName + "\""), requestBody); } } //生成RequestBody对象 return builder.build(); } /** * 获取Mime类型 * * @param filename * @return */ private static String getMimeType(String filename) { FileNameMap fileNameMap = URLConnection.getFileNameMap(); String contentTypeFor = fileNameMap.getContentTypeFor(filename); if (contentTypeFor == null) { contentTypeFor = "application/octet-stream"; } return contentTypeFor; } } 谢谢Steven老师！