Android开发之OkHttp的使用

本篇记录的是Android开发中OkHttp框架的使用，下面介绍OkHttp库的用法，本篇会给出OkHttp的使用demo，demo中包含了常用的get请求、post请求、文件的上传和下载，demo运行的效果如下图所示：

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下面上代码一一说明：

要使用OkHttp，必须在项目中先导入OkHttp，在app模块的build.gradle文件中，加入下面的代码：

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dependencies {      compile fileTree(dir: 'libs' , include: [ '*.jar' ])      testCompile 'junit:junit:4.12'      compile 'com.android.support:appcompat-v7:23.1.1'      compile 'com.squareup.okhttp3:okhttp:3.2.0' }

这样就将OkHttp导入到项目中了。

 

（1）GET请求

最简单的GET请求用法如下：

 

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//简单的Get请求，不带参数 public void simpleGetClick(View view) {      okHttpClient = new OkHttpClient();      Request request = new Request.Builder()              .url( "http://192.168.1.170:8088/okhttp/test_simple_get.php" )              .build();      okHttpClient.newCall(request).enqueue(callback); }

如果请求中要添加Header头和参数，可以用下面的方式：

 

 

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//带参数的Get请求 public void addParamGetClick(View view) {      okHttpClient = new OkHttpClient();      Request request = new Request.Builder()              .addHeader( "token" , "asdlfjkasdljfaskdjfalsjkljalk" )  //请求头中加入参数              .url( "http://192.168.1.170:8088/okhttp/test_param_get.php?username=zhangsan&phone=13888888888" ) //携带参数              .build();      okHttpClient.newCall(request).enqueue(callback); }

需要注意的是，上面的代码中，callback是请求后的回调接口，代码如下：

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//请求后的回调接口 private Callback callback = new Callback() {      @Override      public void onFailure(Call call, IOException e) {          setResult(e.getMessage(), false );      }        @Override      public void onResponse(Call call, Response response) throws IOException {          setResult(response.body().string(), true );      } };

这个回调接口需要注意的是，onResponse和onFailure都不是在UI线程中执行的，所以如果我们要在onResponse或onFailure中进行UI相关的操作，需要在UI线程中进行。

（2）POST请求

比较简单的POST请求，用法如下：

 

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//简单的带参数和Header的post请求 public void simplePostClick(View view) {      okHttpClient = new OkHttpClient();      RequestBody requestBody = new FormBody.Builder()              .add( "username" , "wangwu" )              .add( "password" , "hello12345" )              .add( "gender" , "female" )              .build();      Request request = new Request.Builder()              .url( "http://192.168.1.170:8088/okhttp/test_simple_post.php" )              .post(requestBody)              .addHeader( "token" , "helloworldhelloworldhelloworld" )              .build();      okHttpClient.newCall(request).enqueue(callback); }

这里我们需要先构造一个RequestBody，然后把需要携带的参数放到RequestBody中，然后使用这个RequestBody构建一个Request请求，最后将这个请求放入队列中执行

 

如果我们的POST请求稍微复杂点，比如携带的参数既有文本类型的，又有文件类型的，那么可以用下面的方式来请求：

 

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//带文本参数和文件参数的post请求 public void filePostClick(View view) {      RequestBody fileBody = RequestBody.create(MediaType.parse( "text/plain; charset=utf-8" ), tempFile);      RequestBody requestBody = new MultipartBody.Builder()              .setType(MultipartBody.FORM)              .addFormDataPart( "username" , "wangwu" )              .addFormDataPart( "password" , "hello12345" )              .addFormDataPart( "gender" , "female" )              .addFormDataPart( "file" , "info.txt" , fileBody)              .build();      Request request = new Request.Builder()              .url( "http://192.168.1.170:8088/okhttp/test_param_post.php" )              .post(requestBody)              .addHeader( "token" , "helloworldhelloworldhelloworld" )              .build();      okHttpClient.newCall(request).enqueue(callback); }

上面的代码中，tempFile是一个文本文件，为了POST提交文件和一些其他的参数，我们使用MultipartBody来构建一个请求体，需要注意的是，因为POST的内容含有文件，所以我们必须为这个请求体设置setType(MultipartBody.FORM)

（3）文件的上传

文件上传并显示进度，这个代码稍微有些复杂，下面直接上代码：

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package com.test.testokhttp;   import android.os.Environment; import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.view.View; import android.widget.ProgressBar; import android.widget.TextView; import android.widget.Toast;   import java.io.File; import java.io.IOException; import java.util.concurrent.TimeUnit;   import okhttp3.Call; import okhttp3.Callback; import okhttp3.Interceptor; import okhttp3.MediaType; import okhttp3.MultipartBody; import okhttp3.OkHttpClient; import okhttp3.Request; import okhttp3.RequestBody; import okhttp3.Response; import okhttp3.ResponseBody; import okio.Buffer; import okio.BufferedSink; import okio.BufferedSource; import okio.ForwardingSink; import okio.ForwardingSource; import okio.Okio; import okio.Sink; import okio.Source;   public class UploadActivity extends AppCompatActivity {        private OkHttpClient okHttpClient;      private TextView resultTextView;      private ProgressBar progressBar;      private File tempFile;        @Override      protected void onCreate(Bundle savedInstanceState) {          super .onCreate(savedInstanceState);          setContentView(R.layout.activity_upload);          setTitle( "上传文件并显示进度" );            resultTextView = (TextView) findViewById(R.id.result_textview);          progressBar = (ProgressBar) findViewById(R.id.progress_bar);          progressBar.setMax( 100 );            okHttpClient = new OkHttpClient.Builder()                  .readTimeout( 30 , TimeUnit.SECONDS)                  .connectTimeout( 10 , TimeUnit.SECONDS)                  .writeTimeout( 60 , TimeUnit.SECONDS)                  .build();      }        //点击按钮开始上传文件      public void startUploadClick(View view) {          tempFile = new File(Environment.getExternalStorageDirectory().getAbsolutePath() + File.separator + "test.pdf" );          RequestBody requestBody = new MultipartBody.Builder()                  .setType(MultipartBody.FORM)                  .addFormDataPart( "file" , "test.pdf" , RequestBody.create(MediaType.parse( "application/pdf; charset=utf-8" ), tempFile))                  .build();          ProgressRequestBody progressRequestBody = new ProgressRequestBody(requestBody, progressListener);          Request request = new Request.Builder()                  .url( "http://192.168.1.170:8088/okhttp/test_upload_file.php" )                  .post(progressRequestBody)                  .build();          okHttpClient.newCall(request).enqueue(callback);      }        //通过实现进度回调接口中的方法，来显示进度      private ProgressListener progressListener = new ProgressListener() {          @Override          public void update( long bytesRead, long contentLength, boolean done) {              int progress = ( int ) ( 100.0 * bytesRead / contentLength);              progressBar.setProgress(progress);          }      };        //请求后的回调方法      private Callback callback = new Callback() {          @Override          public void onFailure(Call call, IOException e) {              setResult(e.getMessage(), false );          }            @Override          public void onResponse(Call call, Response response) throws IOException {              setResult(response.body().string(), true );          }      };        //显示请求返回的结果      private void setResult( final String msg, final boolean success) {          runOnUiThread( new Runnable() {              @Override              public void run() {                  if (success) {                      Toast.makeText(UploadActivity. this , "请求成功" , Toast.LENGTH_SHORT).show();                  } else {                      Toast.makeText(UploadActivity. this , "请求失败" , Toast.LENGTH_SHORT).show();                  }                  resultTextView.setText(msg);              }          });      }        //自定义的RequestBody，能够显示进度      public class ProgressRequestBody extends RequestBody {          //实际的待包装请求体          private final RequestBody requestBody;          //进度回调接口          private final ProgressListener progressListener;          //包装完成的BufferedSink          private BufferedSink bufferedSink;            /**           * 构造函数，赋值           *           * @param requestBody      待包装的请求体           * @param progressListener 回调接口           */          public ProgressRequestBody(RequestBody requestBody, ProgressListener progressListener) {              this .requestBody = requestBody;              this .progressListener = progressListener;          }            /**           * 重写调用实际的响应体的contentType           *           * @return MediaType           */          @Override          public MediaType contentType() {              return requestBody.contentType();          }            /**           * 重写调用实际的响应体的contentLength           *           * @return contentLength           * @throws IOException 异常           */          @Override          public long contentLength() throws IOException {              return requestBody.contentLength();          }            /**           * 重写进行写入           *           * @param sink BufferedSink           * @throws IOException 异常           */          @Override          public void writeTo(BufferedSink sink) throws IOException {              if (bufferedSink == null ) {                  //包装                  bufferedSink = Okio.buffer(sink(sink));              }              //写入              requestBody.writeTo(bufferedSink);              //必须调用flush，否则最后一部分数据可能不会被写入              bufferedSink.flush();            }            /**           * 写入，回调进度接口           *           * @param sink Sink           * @return Sink           */          private Sink sink(Sink sink) {              return new ForwardingSink(sink) {                  //当前写入字节数                  long bytesWritten = 0L;                  //总字节长度，避免多次调用contentLength()方法                  long contentLength = 0L;                    @Override                  public void write(Buffer source, long byteCount) throws IOException {                      super .write(source, byteCount);                      if (contentLength == 0 ) {                          //获得contentLength的值，后续不再调用                          contentLength = contentLength();                      }                      //增加当前写入的字节数                      bytesWritten += byteCount;                      //回调                      progressListener.update(bytesWritten, contentLength, bytesWritten == contentLength);                  }              };          }      }        //进度回调接口      interface ProgressListener {          void update( long bytesRead, long contentLength, boolean done);      }   }

上面需要注意的是，上传文件需要实现自定义的RequestBody，也就是上面的ProgressRequestBody，在ProgressRequestBody中获取上传的进度。

（4）文件的下载

下载和上传类似，区别在于，需要我们实习自定义的ResponseBody而不是RequestBody了，下面上代码：

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import android.os.Environment; import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.view.View; import android.widget.ProgressBar; import android.widget.TextView; import android.widget.Toast;   import java.io.File; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.util.concurrent.TimeUnit;   import okhttp3.Call; import okhttp3.Callback; import okhttp3.Interceptor; import okhttp3.MediaType; import okhttp3.OkHttpClient; import okhttp3.Request; import okhttp3.Response; import okhttp3.ResponseBody; import okio.Buffer; import okio.BufferedSource; import okio.ForwardingSource; import okio.Okio; import okio.Source;   public class DownloadActivity extends AppCompatActivity {        private OkHttpClient okHttpClient;      private TextView resultTextView;      private ProgressBar progressBar;      private File tempFile;        @Override      protected void onCreate(Bundle savedInstanceState) {          super .onCreate(savedInstanceState);          setContentView(R.layout.activity_download);          setTitle( "下载文件并显示进度" );            okHttpClient = new OkHttpClient.Builder()                  .addNetworkInterceptor( new Interceptor() {                      @Override public Response intercept(Interceptor.Chain chain) throws IOException {                          Response originalResponse = chain.proceed(chain.request());                          return originalResponse.newBuilder()                                  .body( new ProgressResponseBody(originalResponse.body(), progressListener))                                  .build();                      }                  })                  .connectTimeout( 5 , TimeUnit.SECONDS)                  .readTimeout( 300 , TimeUnit.SECONDS)                  .writeTimeout( 30 , TimeUnit.SECONDS)                  .build();          resultTextView = (TextView) findViewById(R.id.result_textview);          progressBar = (ProgressBar) findViewById(R.id.progress_bar);          tempFile = new File(Environment.getExternalStorageDirectory().getAbsolutePath() + File.separator + System.currentTimeMillis() + ".pdf" );      }        //下载文件      public void startDownloadClick(View view) {          Request request = new Request.Builder()                  .url( "http://192.168.1.170:8088/okhttp/test.pdf" )                  .build();          okHttpClient.newCall(request).enqueue(callback);      }        private ProgressListener progressListener = new ProgressListener() {          @Override          public void update( long bytesRead, long contentLength, boolean done) {              int progress = ( int ) ( 100.0 * bytesRead / contentLength);              progressBar.setProgress(progress);          }      };        //请求后的回调方法      private Callback callback = new Callback() {          @Override          public void onFailure(Call call, IOException e) {              setResult(e.getMessage(), false );          }            @Override          public void onResponse(Call call, Response response) throws IOException {              if (response != null ) {                  //下载完成，保存数据到文件                  InputStream is = response.body().byteStream();                  FileOutputStream fos = new FileOutputStream(tempFile);                  byte [] buf = new byte [ 1024 ];                  int hasRead = 0 ;                  while ((hasRead = is.read(buf)) > 0 ) {                      fos.write(buf, 0 , hasRead);                  }                  fos.close();                  is.close();                  setResult( "下载成功" , true );              }          }      };        //显示请求返回的结果      private void setResult( final String msg, final boolean success) {          runOnUiThread( new Runnable() {              @Override              public void run() {                  if (success) {                      Toast.makeText(DownloadActivity. this , "请求成功" , Toast.LENGTH_SHORT).show();                  } else {                      Toast.makeText(DownloadActivity. this , "请求失败" , Toast.LENGTH_SHORT).show();                  }                  resultTextView.setText(msg);              }          });      }            //自定义的ResponseBody，在其中处理进度      private static class ProgressResponseBody extends ResponseBody {            private final ResponseBody responseBody;          private final ProgressListener progressListener;          private BufferedSource bufferedSource;            public ProgressResponseBody(ResponseBody responseBody, ProgressListener progressListener) {              this .responseBody = responseBody;              this .progressListener = progressListener;          }            @Override public MediaType contentType() {              return responseBody.contentType();          }            @Override public long contentLength() {              return responseBody.contentLength();          }            @Override public BufferedSource source() {              if (bufferedSource == null ) {                  bufferedSource = Okio.buffer(source(responseBody.source()));              }              return bufferedSource;          }            private Source source(Source source) {              return new ForwardingSource(source) {                  long totalBytesRead = 0L;                    @Override public long read(Buffer sink, long byteCount) throws IOException {                      long bytesRead = super .read(sink, byteCount);                      // read() returns the number of bytes read, or -1 if this source is exhausted.                      totalBytesRead += bytesRead != - 1 ? bytesRead : 0 ;                      progressListener.update(totalBytesRead, responseBody.contentLength(), bytesRead == - 1 );                      return bytesRead;                  }              };          }      }        //进度回调接口      interface ProgressListener {          void update( long bytesRead, long contentLength, boolean done);      } }

如果我们在项目中直接使用上面的代码来进行http请求的话，势必会比较麻烦，所以这里我们需要封装上面的代码，尽量在项目中能用简短的代码完成网络请求。另外，一个项目中肯定会有很多个网络请求，我们没必要在每次网络请求中都创建一个OkHttpClient对象，所有的请求公用一个OkHttpClient就可以了。