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Android网络编程系列

前言

上一篇介绍了OkHttp2.x的用法,这一篇文章我们来对照OkHttp2.x版本来看看,OkHttp3使用起来有那些变化。当然,看这篇文章前建议看一下前一篇文章Android网络编程(五)OkHttp2.x用法全解析

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:

<uses-permission android:name="android.permission.INTERNET"/>

2.异步GET请求

惯例,请求百度:

    private void getAsynHttp() {
mOkHttpClient=new OkHttpClient();
Request.Builder requestBuilder = 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(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(), "请求成功", Toast.LENGTH_SHORT).show();
}
});
}
});
}

与2.x版本并没有什么不同,比较郁闷的是回调仍然不在UI线程。

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=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(), "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=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());
}
});
}

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 :

VKJkOH.png

当然不要忘了添加如下权限:

<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

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 = 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 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.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.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.关于取消请求和封装

取消请求仍旧可以调用call.cancel(),这个没有变化,不明白的可以查看上一篇文章Android网络编程(五)OkHttp2.x用法全解析,这里就不赘述了,封装上一篇也讲过仍旧推荐OkHttpFinal,它目前是基于OkHttp3来进行封装的。

8.关于源码Demo

源码Demo很简单就四个按钮用来测试上面讲到的内容:

VKJF6e.png

github源码下载