本文主要整理下关于OkHttp3的一些使用。通过OkHttp框架去请求网络数据，一般包括下面几个步骤：
1. 创建OkHttpClient 对象
2. 创建Request对象（对于get和post请求来说，在创建Request对象时略有不同）
3. 创建Call对象
4. 开始请求，返回Response对象
5. 在Response对象中，获取对应的数据
下面主要列举下如下几种使用情景：
1.同步get请求
2.异步get请求
3.post请求上传键值对
4.post请求上传json串
5.post请求上传文件
6.get请求下载文件
下面会一一列举这六种情况下代码实现。
1.同步get请求
需要说下，关于同步请求的话，不能在UI线程中直接执行，必须放到子线程中去做对应网络请求
/**
* 同步get请求
*/
private void executeNet(){
//1.创建OkHttpClient对象
OkHttpClient mOkHttpClient = new OkHttpClient();
//2.创建Request对象
Request request = new Request.Builder()
.url(URL)
.build();
//3.创建Call对象
Call call=mOkHttpClient.newCall(request);
//4.开始同步请求，返回Response对象
try {
Response mResponse = call.execute();
String result=mResponse.body().string();
Log.i(TAG, "服务器返回结果(同步请求)： " + result);
Bundle mBundle=new Bundle();
mBundle.putString("result",result);
Message msg=new Message();
msg.setData(mBundle);
msg.what=1;
mHandler.sendMessage(msg);
} catch (IOException e) {
e.printStackTrace();
}
}
异步请求，可以直接在UI线程中去执行，但是回调的onResponse()方法并不是UI线程，所以不能在onResponse方法中直接去操作控件
/**
* 异步get请求
*/
private void enqueueNet(){
OkHttpClient mOkHttpClient = new OkHttpClient();
final Request request = new Request.Builder()
.url(URL)
.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 {
//需要注意，response.body().string()调用一次后，response中的流就会被关闭
String result=response.body().string();
response.headers("Set-Cookie");
Log.d(TAG,"服务器返回结果（异步请求）："+result);
Bundle mBundle=new Bundle();
mBundle.putString("result",result);
Message msg=new Message();
msg.setData(mBundle);
msg.what=1;
mHandler.sendMessage(msg);
}
});
}
post请求中，在第二步创建Request对象前，需要先创建RequestBody对象来存储需要上传的不同数据
/**
* 发送POST请求，上传键值对
**/
private void okHttpPostPairs() {
//1.创建OkHttpClient 对象
OkHttpClient mOkHttpClient = new OkHttpClient();
//2.创建Request 对象，在之前，需要先创建RequestBody 对象，用来存储需要上传的数据
RequestBody body = new FormBody.Builder()
.add("login_username", "leijx")
.add("login_password", "123456")
.build();
Request request = new Request.Builder()
.url(URL)
.post(body)
.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 {
List<String> setCookieList = response.headers("Set-Cookie");
Log.i(TAG, "repose result: " + response.body().string());
}
});
}
4.post请求上传json串
/**
* post请求
* 上传json
*/
private void enqueueNet_post(){
//1.创建OkHttpClient 对象
OkHttpClient mOkHttpClient = new OkHttpClient();
//2.创建Request 对象，在之前，需要先创建RequestBody 对象，用来存储需要上传的数据
RequestBody mRequestBody = RequestBody.create(MediaType.parse("application/json;charset=utf-8"),"这是一个json串");
Request mRequest = new Request.Builder()
.url(URL)
.post(mRequestBody)
.build();
Call mCall = mOkHttpClient.newCall(mRequest);
mCall.enqueue(new Callback() {
@Override
public void onFailure(Call call, IOException e) {
}
@Override
public void onResponse(Call call, Response response) throws IOException {
}
});
}
5.post请求上传文件
/**
* POST请求，上传图片
**/
private void okHttpUpLoad() {
OkHttpClient mOkHttpClient = new OkHttpClient();
File file = new File(Environment.getExternalStorageDirectory() + "/ic_launcher.png");
//不带参数的RequestBody
// RequestBody body = RequestBody.create(MediaType.parse("image/png"),file);
//带参数的RequestBody
// MultipartBody.Builder builder = new MultipartBody.Builder();
// builder.addFormDataPart("filename", "testpng");
// builder.addFormDataPart("file", file.getName(), RequestBody.create(MediaType.parse("image/png"), file));
// RequestBody body = builder.build();
RequestBody body = new MultipartBody.Builder()
.addFormDataPart("filename", "testpng")
.addFormDataPart("file", file.getName(), RequestBody.create(MediaType.parse("image/png"), file))
.build();
Request request = new Request.Builder()
.url(URL)
.post(body)
.addHeader("Cookie", "test")
.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 {
Log.i(TAG, "upload success, repose result: " + response.body().string());
}
});
}
/**
* 下载文件
**/
private void okHttpDownload() {
OkHttpClient mOkHttpClient = new OkHttpClient();
final File file = new File(Environment.getExternalStorageDirectory().toString() + "/default.png");
Request request = new Request.Builder().url(URL).build();
Call call = mOkHttpClient.newCall(request);
call.enqueue(new Callback() {
@Override
public void onFailure(Call call, IOException e) {
Log.i(TAG, "failure: ");
e.printStackTrace();
}
@Override
public void onResponse(Call call, Response response) throws IOException {
Log.i(TAG, "onResponse");
InputStream is = null;
byte[] buf = new byte[2048];
int len = 0;
FileOutputStream fos = null;
try {
long total = response.body().contentLength();
Log.e(TAG, "total------>" + total);
long current = 0;
//获取对应流
is = response.body().byteStream();
fos = new FileOutputStream(file);
while ((len = is.read(buf)) != -1) {
current += len;
fos.write(buf, 0, len);
Log.e(TAG, "current------>" + current);
}
fos.flush();
Log.i(TAG, "download file success");
} catch (IOException e) {
Log.e(TAG, e.toString());
} finally {
try {
if (is != null) {
is.close();
}
if (fos != null) {
fos.close();
}
} catch (IOException e) {
Log.e(TAG, e.toString());
}
}
}
});
}