1.使用前準備
Android Studio 配置gradle：
compile 'com.squareup.okhttp3:okhttp:3.2.0'
compile 'com.squareup.okio:okio:1.7.0'
添加網絡權限：
2.異步GET請求
private void getAsynHttp() {
mOkHttpClient=new OkHttpClient();
Request.Builder requestBuilder = new Request.Builder().url("http://www.baidu.com");
//可以省略，默認是GET請求
requestBuilder.method("GET",null);
Request request = requestBuilder.build();
Call mcall= mOkHttpClient.newCall(request);
mcall.enqueue(new Callback() {
@Override
public void onFailure(Call call, IOException e) {
}
@Override
public void onResponse(Call call, Response response) throws IOException {
if (null != response.cacheResponse()) {
String str = response.cacheResponse().toString();
Log.i("wangshu", "cache---" + str);
} else {
response.body().string();
String str = response.networkResponse().toString();
Log.i("wangshu", "network---" + str);
}
runOnUiThread(new Runnable() {
@Override
public void run() {
Toast.makeText(getApplicationContext(), "請求成功", Toast.LENGTH_SHORT).show();
}
});
}
});
}
2.異步POST請求
OkHttp3異步POST請求和OkHttp2.x有一些差別就是沒有FormEncodingBuilder這個類，替代它的是功能更加強大的FormBody：
private void postAsynHttp() {
mOkHttpClient=new OkHttpClient();
RequestBody formBody = new FormBody.Builder()
.add("size", "10")
.build();
Request request = new Request.Builder()
.url("http://api.1-blog.com/biz/bizserver/article/list.do")
.post(formBody)
.build();
Call call = mOkHttpClient.newCall(request);
call.enqueue(new Callback() {
@Override
public void onFailure(Call call, IOException e) {
}
@Override
public void onResponse(Call call, Response response) throws IOException {
String str = response.body().string();
Log.i("wangshu", str);
runOnUiThread(new Runnable() {
@Override
public void run() {
Toast.makeText(getApplicationContext(), "請求成功", Toast.LENGTH_SHORT).show();
}
});
}
});
}
3.異步上傳文件
上傳文件本身也是一個POST請求，上一篇沒有講，這里我們補上。首先定義上傳文件類型：
public static final MediaType MEDIA_TYPE_MARKDOWN
= MediaType.parse("text/x-markdown; charset=utf-8");
將sdcard根目錄的wangshu.txt文件上傳到服務器上：
private void postAsynFile() {
mOkHttpClient=new OkHttpClient();
File file = new File("/sdcard/wangshu.txt");
Request request = new Request.Builder()
.url("https://api.github.com/markdown/raw")
.post(RequestBody.create(MEDIA_TYPE_MARKDOWN, file))
.build();
mOkHttpClient.newCall(request).enqueue(new Callback() {
@Override
public void onFailure(Call call, IOException e) {
}
@Override
public void onResponse(Call call, Response response) throws IOException {
Log.i("wangshu",response.body().string());
}
});
}
當然如果想要改為同步的上傳文件只要調用 mOkHttpClient.newCall(request).execute()就可以了。
在wangshu.txt文件中有一行字“Android網絡編程（六）OkHttp3用法全解析”我們運行程序點擊發送文件按鈕，最終請求網絡返回的結果就是我們txt文件中的內容 ：
這里寫圖片描述
當然不要忘了添加如下權限：
4.異步下載文件
下載文件同樣在上一篇沒有講到，實現起來比較簡單，在這里下載一張圖片，我們得到Response后將流寫進我們指定的圖片文件中就可以了。
private void downAsynFile() {
mOkHttpClient = new OkHttpClient();
String url = "http://img.my.csdn.net/uploads/201603/26/1458988468_5804.jpg";
Request request = new Request.Builder().url(url).build();
mOkHttpClient.newCall(request).enqueue(new Callback() {
@Override
public void onFailure(Call call, IOException e) {
}
@Override
public void onResponse(Call call, Response response) {
InputStream inputStream = response.body().byteStream();
FileOutputStream fileOutputStream = null;
try {
fileOutputStream = new FileOutputStream(new File("/sdcard/wangshu.jpg"));
byte[] buffer = new byte[2048];
int len = 0;
while ((len = inputStream.read(buffer)) != -1) {
fileOutputStream.write(buffer, 0, len);
}
fileOutputStream.flush();
} catch (IOException e) {
Log.i("wangshu", "IOException");
e.printStackTrace();
}
Log.d("wangshu", "文件下載成功");
}
});
}
5.異步上傳Multipart文件
這種場景很常用，我們有時會上傳文件同時還需要傳其他類型的字段，OkHttp3實現起來很簡單，需要注意的是沒有服務器接收我這個Multipart文件，所以這里只是舉個例子，具體的應用還要結合實際工作中對應的服務器。
首先定義上傳文件類型：
private static final MediaType MEDIA_TYPE_PNG = MediaType.parse("image/png");
private void sendMultipart(){
mOkHttpClient = new OkHttpClient();
RequestBody requestBody = new MultipartBody.Builder()
.setType(MultipartBody.FORM)
.addFormDataPart("title", "wangshu")
.addFormDataPart("image", "wangshu.jpg",
RequestBody.create(MEDIA_TYPE_PNG, new File("/sdcard/wangshu.jpg")))
.build();
Request request = new Request.Builder()
.header("Authorization", "Client-ID " + "...")
.url("https://api.imgur.com/3/image")
.post(requestBody)
.build();
mOkHttpClient.newCall(request).enqueue(new Callback() {
@Override
public void onFailure(Call call, IOException e) {
}
@Override
public void onResponse(Call call, Response response) throws IOException {
Log.i("wangshu", response.body().string());
}
});
}
6.設置超時時間和緩存
和OkHttp2.x有區別的是不能通過OkHttpClient直接設置超時時間和緩存了，而是通過OkHttpClient.Builder來設置，通過builder配置好OkHttpClient后用builder.build()來返回OkHttpClient，所以我們通常不會調用new OkHttpClient()來得到OkHttpClient，而是通過builder.build()：
File sdcache = getExternalCacheDir();
int cacheSize = 10 * 1024 * 1024;
OkHttpClient.Builder builder = new OkHttpClient.Builder()
.connectTimeout(15, TimeUnit.SECONDS)
.writeTimeout(20, TimeUnit.SECONDS)
.readTimeout(20, TimeUnit.SECONDS)
.cache(new Cache(sdcache.getAbsoluteFile(), cacheSize));
OkHttpClient mOkHttpClient=builder.build();
7.關于取消請求和封裝
OkHttpFinal，它目前是基于OkHttp3來進行封裝的。鏈接描述
8.關于源碼Demo
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