1.使用前准备
Android Studio 配置gradle：
compile 'com.squareup.okhttp3:okhttp:3.2.0'
compile 'com.squareup.okio:okio:1.7.0'
添加网络权限：
2.异步GET请求
private void getAsynHttp(){
mOkHttpClient=newOkHttpClient();
Request.BuilderrequestBuilder = new Request.Builder().url("http://www.baidu.com");
//可以省略，默认是GET请求
requestBuilder.method("GET",null);
Request request =requestBuilder.build();
Call mcall= mOkHttpClient.newCall(request);
mcall.enqueue(newCallback() {
@Override
public voidonFailure(Call call, IOException e) {
}
@Override
public voidonResponse(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(newRunnable() {
@Override
public voidrun() {
Toast.makeText(getApplicationContext(),"请求成功", Toast.LENGTH_SHORT).show();
}
});
}
});
}
2.异步POST请求
OkHttp3异步POST请求和OkHttp2.x有一些差别就是没有FormEncodingBuilder这个类，替代它的是功能更加强大的FormBody：
private void postAsynHttp(){
mOkHttpClient=newOkHttpClient();
RequestBody formBody =new FormBody.Builder()
.add("size", "10")
.build();
Request request = newRequest.Builder()
.url("http://api.1-blog.com/biz/bizserver/article/list.do")
.post(formBody)
.build();
Call call =mOkHttpClient.newCall(request);
call.enqueue(newCallback() {
@Override
public voidonFailure(Call call, IOException e) {
}
@Override
public voidonResponse(Call call, Response response) throws IOException {
String str =response.body().string();
Log.i("wangshu", str);
runOnUiThread(new Runnable() {
@Override
publicvoid run() {
Toast.makeText(getApplicationContext(), "请求成功", Toast.LENGTH_SHORT).show();
}
});
}
});
}
3.异步上传文件
上传文件本身也是一个POST请求，上一篇没有讲，这里我们补上。首先定义上传文件类型：
public static final MediaType MEDIA_TYPE_MARKDOWN
=MediaType.parse("text/x-markdown; charset=utf-8");
将sdcard根目录的wangshu.txt文件上传到服务器上：
private void postAsynFile() {
mOkHttpClient=newOkHttpClient();
File file = newFile("/sdcard/wangshu.txt");
Request request = newRequest.Builder()
.url("https://api.github.com/markdown/raw")
.post(RequestBody.create(MEDIA_TYPE_MARKDOWN,file))
.build();
mOkHttpClient.newCall(request).enqueue(new Callback() {
@Override
public voidonFailure(Call call, IOException e) {
}
@Override
public voidonResponse(Call call, Response response) throws IOException {
Log.i("wangshu",response.body().string());
}
});
}
当然如果想要改为同步的上传文件只要调用 mOkHttpClient.newCall(request).execute()就可以了。
在wangshu.txt文件中有一行字“Android网络编程（六）OkHttp3用法全解析”我们运行程序点击发送文件按钮，最终请求网络返回的结果就是我们txt文件中的内容：
这里写图片描述
当然不要忘了添加如下权限：
4.异步下载文件
下载文件同样在上一篇没有讲到，实现起来比较简单，在这里下载一张图片，我们得到Response后将流写进我们指定的图片文件中就可以了。
private void downAsynFile() {
mOkHttpClient = newOkHttpClient();
String url ="http://img.my.csdn.net/uploads/201603/26/1458988468_5804.jpg";
Request request = newRequest.Builder().url(url).build();
mOkHttpClient.newCall(request).enqueue(new Callback() {
@Override
public voidonFailure(Call call, IOException e) {
}
@Override
public voidonResponse(Call call, Response response) {
InputStreaminputStream = response.body().byteStream();
FileOutputStreamfileOutputStream = null;
try {
fileOutputStream = new FileOutputStream(newFile("/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", "文件下载成功");
}
});
}
5.异步上传Multipart文件
这种场景很常用，我们有时会上传文件同时还需要传其他类型的字段，OkHttp3实现起来很简单，需要注意的是没有服务器接收我这个Multipart文件，所以这里只是举个例子，具体的应用还要结合实际工作中对应的服务器。
首先定义上传文件类型：
private static finalMediaType MEDIA_TYPE_PNG = MediaType.parse("image/png");
private void sendMultipart(){
mOkHttpClient = newOkHttpClient();
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 = newRequest.Builder()
.header("Authorization", "Client-ID " +"...")
.url("https://api.imgur.com/3/image")
.post(requestBody)
.build();
mOkHttpClient.newCall(request).enqueue(new Callback() {
@Override
public voidonFailure(Call call, IOException e) {
}
@Override
public voidonResponse(Call call, Response response) throws IOException {
Log.i("wangshu", response.body().string());
}
});
}
6.设置超时时间和缓存
和OkHttp2.x有区别的是不能通过OkHttpClient直接设置超时时间和缓存了，而是通过OkHttpClient.Builder来设置，通过builder配置好OkHttpClient后用builder.build()来返回OkHttpClient，所以我们通常不会调用new
OkHttpClient()来得到OkHttpClient，而是通过builder.build()：
File sdcache =getExternalCacheDir();
int cacheSize = 10 * 1024* 1024;
OkHttpClient.Builderbuilder = new OkHttpClient.Builder()
.connectTimeout(15, TimeUnit.SECONDS)
.writeTimeout(20,TimeUnit.SECONDS)
.readTimeout(20,TimeUnit.SECONDS)
.cache(newCache(sdcache.getAbsoluteFile(), cacheSize));
OkHttpClientmOkHttpClient=builder.build();
7.关于取消请求和封装
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