okHttp3 是一个 Android的基于Http的网络开源框架，是由 square 公司开发。
现在网上比较推荐的两个 Android 网络开源框架，一个是 okHttp，另一个是 Retrofit ，而 Retrofit 是根据 okHttp封装的框架。所以关于Android网络部分，okHttp是必须要学习的一个知识。
[官网地址] (https://github.com/square/okhttp)
项目中引用 okHttp3 只需要在 app 的 build.gradle 中引用 compile ‘com.squareup.okhttp3:okhttp:3.6.0’ 即可。
[慕课网洪洋大神的okHttp视频] (http://www.imooc.com/learn/764) [参考的简书文章] (http://www.jianshu.com/p/964bb1b2d345) [参考的文章] (http://blog.csdn.net/itachi85/article/details/51190687)
1.okHttp3的基本用法 首先，不管是 Get 请求还是 Post 请求，同步或者异步，okHttp3的请求总体分为三步:
构造出一个okHttp3下的Request对象通过这个Request对象，构造出一个Call对象调用这个call对象的同步或者异步方法执行网络访问示例如下:
//构造出一个Request对象，address是访问的服务器地址,当前示例是get方式访问 Request request = new Request.Builder().url(address).get().build(); //通过上面的request对象，构造出一个Call对象，sOkHttpClient为全局的OkHttpClient对象 Call call = sOkHttpClient.newCall(request); //call执行enqueue(异步)或者execute(同步)，callback为异步执行时的回调对象 call.enqueue(callback);2.okHttp3下的Get请求方式
/** * Get请求方法 * @param view */ public void doGet(View view){ String address = baseUrl + "login?username=hblolj&password=123456"; HttpUtils.sendOkHttpRequestByGet(address, new Callback() { //请求失败的回调 @Override public void onFailure(Call call, IOException e) { Log.i(TAG, "onFailure: " + e.getMessage()); e.printStackTrace(); } //请求成功的回调 @Override public void onResponse(Call call, Response response) throws IOException { //拿到服务器返回的数据 final String result = response.body().string(); Log.i(TAG, "onResponse: " + result); //因为是enqueue异步执行，所以只有在主线程中才可以更新UI runOnUiThread(new Runnable() { @Override public void run() { tv_result.setText(result); } }); } }); } /** * HttpUtils中的Get请求方法 * @param address get方式的请求地址 * @param callback 回调对象 */ public static void sendOkHttpRequestByGet(String address , Callback callback){ Request request = new Request.Builder().url(address).get().build(); Call call = sOkHttpClient.newCall(request); call.enqueue(callback); }3.okHttp3下的Post请求方式(键值对型)
Tips:post请求默认的类型是：application/x-www-form-urlencoded
//在OkHttp3的源码中FormBody 的源码 private static final MediaType CONTENT_TYPE = MediaType.parse("application/x-www-form-urlencoded");根据 MediaType 的类型，post选择对上传的数据是否进行编码处理。如果为 multipart/form-data 类型表示上传的是文件，则不用进行编码处理。
/** * Post请求方法 * @param view */ public void doPost(View view){ //登录接口 String address = baseUrl + "login"; Map<String, String> map = new HashMap<>(); map.put("username", "hblolj"); map.put("password", "123456"); HttpUtils.sendOkHttpRequestByPost(address, new Callback() { @Override public void onFailure(Call call, IOException e) { Log.i(TAG, "onFailure: " + e.getMessage()); e.printStackTrace(); } @Override public void onResponse(Call call, Response response) throws IOException { final String result = response.body().string(); Log.i(TAG, "onResponse: " + result); runOnUiThread(new Runnable() { @Override public void run() { tv_result.setText(result); } }); } }, map); } /** * HttpUtils中的post请求方法 * @param address post请求的地址 * @param callback 回调对象 * @param maps post请求的参数 */ public static void sendOkHttpRequestByPost(String address, Callback callback, Map<String, String> maps){ //根据参数中的maps拼装出RequestBody，用来保存参数，默认的MediaType RequestBody requestBody = new FormBody.Builder() .add("username", maps.get("username")) .add("password", maps.get("password")) .build(); //将请求地址与请求参数设置给Request Request request = new Request.Builder().url(address).post(requestBody).build(); //构造Call对象 Call call = sOkHttpClient.newCall(request); //异步执行网络访问 call.enqueue(callback); }4.okHttp3下的Post请求方式(String型)
/** * Post请求上传字符串 * @param view */ public void doPostString(View view){ String address = baseUrl + "postString"; HttpUtils.sendOkHttpRequestByPostString(address, new Callback() { @Override public void onFailure(Call call, IOException e) { Log.i(TAG, "onFailure: " + e.getMessage()); e.printStackTrace(); } @Override public void onResponse(Call call, Response response) throws IOException { final String result = response.body().string(); Log.i(TAG, "onResponse: " + result); runOnUiThread(new Runnable() { @Override public void run() { tv_result.setText(result); } }); } }, "我是通过PostString传递的字符内容"); } /** * Post上传字符串方法 * @param address 服务器地址 * @param callback 回调对象 * @param value 上传的字符串 */ public static void sendOkHttpRequestByPostString(String address, Callback callback, String value){ //相对于键值对类型，这里指定了MediaType RequestBody requestBody = RequestBody.create(MediaType.parse("text/plain;charset=utf-8"), value); //构造Request Request request = new Request.Builder().url(address).post(requestBody).build(); //构造Call Call call = sOkHttpClient.newCall(request); //异步执行 call.enqueue(callback); }5.okHttp3下的Post请求方式(File型)
/** * Post请求上传文件 * @param view */ public void doPostFile(View view){ String address = baseUrl + "postFile"; //从内存卡获取文件 File file = new File(Environment.getExternalStorageDirectory(), "shareimg.png"); if (!file.exists()){ Log.i(TAG, "文件不存在"); tv_result.setText("文件不存在!"); return; } HttpUtils.sendOkHttpRequestByPostFile(address, new Callback() { @Override public void onFailure(Call call, IOException e) { Log.i(TAG, "onFailure: " + e.getMessage()); e.printStackTrace(); } @Override public void onResponse(Call call, Response response) throws IOException { final String result = response.body().string(); Log.i(TAG, "onResponse: " + result); runOnUiThread(new Runnable() { @Override public void run() { tv_result.setText(result); } }); } }, file); } /** * Post方法上传文件 * @param address 完整的请求地址 * @param callback 回调对象 * @param file 上传的文件对象 */ public static void sendOkHttpRequestByPostFile(String address, Callback callback, File file){ //指定了MediaType为application/octet-stream，并且传入File生成requestBody RequestBody requestBody = RequestBody.create(MediaType.parse("application/octet-stream"), file); //构造Request Request request = new Request.Builder().url(address).post(requestBody).build(); //构造Call Call call = sOkHttpClient.newCall(request); //异步执行 call.enqueue(callback); }6.okHttp3下的文件上传
/** * okHttp3下的文件上传 * @param view */ public void doUpload(View view){ String address = baseUrl + "uploadFile"; File file = new File(Environment.getExternalStorageDirectory(), "tagPicture.jpg"); if (!file.exists()){ Log.i(TAG, "文件不存在"); tv_result.setText("文件不存在!"); return; } HttpUtils.sendOkHttpRequestByUpload(address, new Callback() { @Override public void onFailure(Call call, IOException e) { Log.i(TAG, "onFailure: " + e.getMessage()); e.printStackTrace(); } @Override public void onResponse(Call call, Response response) throws IOException { final String result = response.body().string(); Log.i(TAG, "onResponse: " + result); runOnUiThread(new Runnable() { @Override public void run() { tv_result.setText(result); } }); } }, file); } /** * okHttp3下的文件时上传 * @param address 访问的地址 * @param callback 回调对象 * @param file 上传的文件 */ public static void sendOkHttpRequestByUpload(String address, Callback callback, File file){ //构造MultipartBody(复合Body) MultipartBody multipartBody = new MultipartBody.Builder() //配置上传的类型 .setType(MultipartBody.FORM) //上传的普通键值对 .addFormDataPart("username", "hblolj") .addFormDataPart("password", "123456") //参数对应为name, fileName, reuqestBody .addFormDataPart("picture", "一张照片.jpg", //构造文件类型RequestBody RequestBody.create(MediaType.parse("application/octet-stream"), file)) .build(); //构造Request Request request = new Request.Builder().url(address).post(multipartBody).build(); //构造Call Call call = sOkHttpClient.newCall(request); //异步执行 call.enqueue(callback); }7.okHttp3下的文件下载
/** * okhttp3下的文件下载 * @param view */ public void doDownloadFile(View view){ //下载地址 String address = baseUrl + "files/picture.jpg"; HttpUtils.sendOkHttpRequestByDownloadFile(address, new Callback() { @Override public void onFailure(Call call, IOException e) { Log.i(TAG, "onFailure: " + e.getMessage()); e.printStackTrace(); } @Override public void onResponse(Call call, Response response) throws IOException { //拿到服务器下载文件的输入流 InputStream is = response.body().byteStream(); //本地新建文件 File file = new File(Environment.getExternalStorageDirectory(), "一张照片6666.jpg"); //拿到新建文件的输出流 FileOutputStream fout = new FileOutputStream(file); //模板代码，将下载文件的输入流写到新建文件 int len = 0; byte[] buf = new byte[128]; while((len = is.read(buf)) != -1){ fout.write(buf, 0, len); } fout.flush(); fout.close(); is.close(); runOnUiThread(new Runnable() { @Override public void run() { tv_result.setText("下载成功"); } }); } }); } /** * okhttp3下的文件下载 * 找到下载地址，就是普通的Get访问 * @param address 下载地址 * @param callback 回调对象 */ public static void sendOkHttpRequestByDownloadFile(String address, Callback callback){ Request request = new Request.Builder().url(address).get().build(); Call call = sOkHttpClient.newCall(request); call.enqueue(callback); }8.okHttp3下的Session保持与缓存
/** * 全局的okHttpClient */ private static OkHttpClient sOkHttpClient = new OkHttpClient.Builder().cookieJar(new CookieJar() { private Map<String, List<Cookie>> cookieStore = new HashMap<String, List<Cookie>>(); @Override public void saveFromResponse(HttpUrl url, List<Cookie> cookies) { //根据请求的host保存cookies到内存，达到session的保存 Log.d("HttpUtils", "host: " + url.host()); cookieStore.put(url.host(), cookies); } @Override public List<Cookie> loadForRequest(HttpUrl url) { List<Cookie> cookies = cookieStore.get(url.host()); return cookies!=null?cookies : new ArrayList<Cookie>(); } }) //设置连接超时时间 .connectTimeout(1500, TimeUnit.MILLISECONDS) .readTimeout(2000, TimeUnit.MILLISECONDS) .writeTimeout(2000, TimeUnit.MILLISECONDS) //设置保存缓存的文件以及大小限制 .cache(new Cache(file , 10*1024*1024)) .build();9.okHttp3的框架封装
参考开始的推荐文章
