Android基于OkHttp实现下载和上传图片

public class MainActivity extends AppCompatActivity {

  private String Path = "https://10.url.cn/eth/ajNVdqHZLLAxibwnrOxXSzIxA76ichutwMCcOpA45xjiapneMZsib7eY4wUxF6XDmL2FmZEVYsf86iaw/";
  private static final int SUCCESS = 993;
  private static final int FALL = 814;
  Handler handler = new Handler() {
    @Override
    public void handleMessage(Message msg) {
      switch (msg.what) {
        //加载网络成功,进行UI的更新,处理得到的图片资源
        case SUCCESS:
          //通过message,拿到字节数组
          byte[] Picture = (byte[]) msg.obj;
          //使用BitmapFactory工厂,把字节数组转换为bitmap
          Bitmap bitmap = BitmapFactory.decodeByteArray(Picture, 0, Picture.length);
          //通过ImageView,设置图片
          mImageView_okhttp.setImageBitmap(bitmap);
          break;
        //当加载网络失败,执行的逻辑代码
        case FALL:
          Toast.makeText(MainActivity.this, "网络异常", Toast.LENGTH_SHORT).show();
          break;

        default:
          break;
      }
    }
  };
  private ImageView mImageView_okhttp;

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    //初始化控件
    initView();
  }

  private void initView() {
    mImageView_okhttp = (ImageView) findViewById(R.id.imageView_okhttp);
  }

  /**
   * 根据点击事件获取络上的图片资源,使用的是OKhttp框架
   *
   * @param view
   */
  public void Picture_okhttp_bt(View view) {
    //1. 创建OKhttpClient对象
    OkHttpClient okHttpClient = new OkHttpClient();
    //2.建立Request对象,设置参数,请求方式如果是get,就不用设置,默认使用的就是get
    Request request = new Request.Builder()
        .url(Path)//设置请求网址
        .build();//建立request对象
    //3.创建一个Call对象,参数是request对象,发送请求
    Call call = okHttpClient.newCall(request);
    //4.异步请求,请求加入调度
    call.enqueue(new Callback() {
      @Override//请求失败回调
      public void onFailure(Call call, IOException e) {
        handler.sendEmptyMessage(FALL);
      }

      @Override//请求成功回调
      public void onResponse(Call call, Response response) throws IOException {
        //得到从网上获取资源,转换成我们想要的类型
        byte[] Picture_bt = response.body().bytes();
        //通过handler更新UI
        Message message = handler.obtainMessage();
        message.obj = Picture_bt;
        message.what = SUCCESS;
        handler.sendMessage(message);

      }
    });
  }

  //当按钮点击时,执行使用OKhttp上传图片到服务器(http://blog.csdn.net/tangxl2008008/article/details/51777355)
  //注意:有时候上传图片失败,是服务器规定还要上传一个Key,如果开发中关于网络这一块出现问题,就多和面试官沟通沟通
  public void uploading(View view) {
    //图片上传接口地址
    String url = "https://www.718shop.com/sell/sell.m.picture.upload.do";
    //创建上传文件对象
    File file = new File(Environment.getExternalStorageDirectory(), "big.jpg");

    //创建RequestBody封装参数
    RequestBody fileBody = RequestBody.create(MediaType.parse("application/octet-stream"), file);
    //创建MultipartBody,给RequestBody进行设置
    MultipartBody multipartBody = new MultipartBody.Builder()
        .setType(MultipartBody.FORM)
        .addFormDataPart("image", "big.jpg", fileBody)
        .build();
    //创建Request
    Request request = new Request.Builder()
        .url(url)
        .post(multipartBody)
        .build();

    //创建okhttp对象
    OkHttpClient okHttpClient = new OkHttpClient.Builder()
        .connectTimeout(10, TimeUnit.SECONDS)
        .readTimeout(10, TimeUnit.SECONDS)
        .writeTimeout(10, TimeUnit.SECONDS)
        .build();

    //上传完图片,得到服务器反馈数据
    okHttpClient.newCall(request).enqueue(new Callback() {
      @Override
      public void onFailure(Call call, IOException e) {
        Log.e("ff", "uploadMultiFile() e=" + e);
      }

      @Override
      public void onResponse(Call call, Response response) throws IOException {
        Log.i("ff", "uploadMultiFile() response=" + response.body().string());
      }
    });


  }

}

<RelativeLayout
  xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:tools="http://schemas.android.com/tools"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  tools:context="com.sn.picture_okhttp.MainActivity">


  <Button
    android:id="@+id/button"
    android:onClick="Picture_okhttp_bt"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="下载图片"
    android:layout_alignParentTop="true"
    android:layout_centerHorizontal="true"
    android:layout_marginTop="59dp"/>

  <Button
    android:text="上传图片"
    android:onClick="uploading"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@+id/button2"
    android:layout_alignParentTop="true"
    android:layout_alignLeft="@+id/button"
    android:layout_alignStart="@+id/button"/>

  <ImageView
    android:id="@+id/imageView_okhttp"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentBottom="true"
    android:layout_centerHorizontal="true"/>

</RelativeLayout>

implementation 'com.squareup.okhttp3:okhttp:3.4.2'