网络框架Retrofit的Get请求

Retrofit(改良)框架是Square公司出品的目前非常流行的网络框架,效率高,实现简单,运用注解和动态代理,极大的简化了网络请求的繁琐步骤,非常适合处理REST ful(一种风格)网络请求.目前Retrofit版本是2(可以说是Square公司之前出品okhttp的升级版)

特点:

• 性能好,处理快,使用简单.(速度比Volley更快)
  
• 使用REST API非常方便
  
• 支持NIO(新的IO API，可以替代标准的Java IO API)
  
• Retrofit默认使用okhttp处理网络请求；
  
• 默认使用Gson解析
  

搭建Retrofit2.0的环境:

1.在项目的build.gradle中添加依赖

compile 'com.squareup.retrofit2:retrofit:2.3.0'compile 'com.squareup.retrofit2:converter-gson:2.0.0-beta4'compile 'com.squareup.retrofit2:converter-scalars:2.3.0'compile 'com.github.bumptech.glide:glide:4.0.0-RC1'

前三个是他的依赖,最后一个是glide图片框架依赖

2.在项目的清单文件中添加网络权限

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

//网络请求的方法返回call:"一共两个一个是Get请求验证登录,一个是Get请求图片"
public class ApiHome {    private BaseService baseService;    private static volatile ApiHome instance;    public ApiHome(BaseService baseService) {        this.baseService = baseService;    }    public ApiHome() {    }    public static ApiHome getInstance() {        if (instance == null) {            synchronized (ApiHome.class) {                if (instance == null) {                    instance = new ApiHome();                }            }        }        return instance;    }

 public Call<ResponseBody> getData(String qq, String pwd) {        if (baseService == null) {            baseService = Home.getBaseService();        }        StringBuffer stringBuffer = new StringBuffer();        //http://169.254.34.113/users/Guolei1130        //拼接参数        stringBuffer.append(Constant.URL_BASE).append("web/").append("LoginServlet?")                .append("qq="+qq)                .append("&pwd=" + pwd);        return baseService.baseGetRequest(stringBuffer.toString());    }    public Call<ResponseBody> getImage() {        if (baseService == null) {            baseService = Home.getBaseService();        }        StringBuffer stringBuffer = new StringBuffer();        //http://169.254.34.113/images/2017-06-02/c591370512f1d14c96d72ab383b5d153.jpeg        //拼接参数        stringBuffer.append(Constant.IMAGE_URL).append("images/").append("2017-06-02/c591370512f1d14c96d72ab383b5d153.jpeg");        return baseService.baseGetImage(stringBuffer.toString());    }}

另外他需要一个接口来写他的Get请求的网址

public interface BaseService {    //get请求    @GET    Call<ResponseBody> baseGetRequest(@Url String user);    @GET    Call<ResponseBody> baseGetImage(@Url String user);}

然后通过类接收使之在请求类实现

public class Home {    static Retrofit retrofit = new Retrofit.Builder()            .baseUrl(Constant.URL_BASE)            .addConverterFactory(GsonConverterFactory.create())            .build();    public static BaseService getBaseService() {        return retrofit.create(BaseService.class);    }}

当然重要的还得获取他的网址

public final class Constant {    public static final String BASE_URL="https://api.github.com/";    public static final String IMAGE_URL="http://omsproductionimg.yangkeduo.com/";    public static final String URL_BASE="http://169.254.125.233:8080/";}

最后在MainActivity中来给他吧数据展示

@Overridepublic void onClick(View view) {    switch (view.getId()) {        case R.id.button_get_reg://这个是展示Get请求登入页面的            String qq = name.getText().toString();            String pwd = password.getText().toString();            call = ApiHome.getInstance().getData(qq, pwd);            call.enqueue(new Callback<ResponseBody>() {                @Override                public void onResponse(Call<ResponseBody> call, Response<ResponseBody> response) {                    try {                        String result = response.body().string();                        Toast.makeText(MainActivity.this, result, Toast.LENGTH_LONG).show();                    } catch (IOException e) {                        e.printStackTrace();}}                @Override                public void onFailure(Call<ResponseBody> call, Throwable t) {                }});            break;        case R.id.button_get_pic://这个是显示图片的            imageCall = ApiHome.getInstance().getImage();            imageCall.enqueue(new Callback<ResponseBody>() {                @Override                public void onResponse(Call<ResponseBody> call, Response<ResponseBody> response) {                    try {                        byte[] be = response.body().bytes();                        Bitmap bitmap = BitmapFactory.decodeByteArray(be, 0, be.length);                        imageView_login.setImageBitmap(bitmap);                        saveBitmapToSDCard(bitmap, response.body().string());                        Toast.makeText(MainActivity.this, "保存成功", Toast.LENGTH_LONG).show();                    } catch (IOException e) {                        e.printStackTrace();                    }}                @Override                public void onFailure(Call<ResponseBody> call, Throwable t) {                }});            break;        case R.id.button_get_file:            break;    }}//销毁@Overrideprotected void onDestroy() {    super.onDestroy();    if (call != null) {        call.cancel();    }}/** * 保存bitmap到SD卡 * * @param bitmap * @param imagename */public static String saveBitmapToSDCard(Bitmap bitmap, String imagename) {    String path = "/sdcard/" + "img-" + imagename + ".jpg";    FileOutputStream fos = null;    try {        fos = new FileOutputStream(path);        if (fos != null) {            bitmap.compress(Bitmap.CompressFormat.JPEG, 90, fos);            fos.close();        }        return path;    } catch (Exception e) {        e.printStackTrace();    }    return null;}