Retrofit(一)、Retrofit+OkHttp实现简单的Get与Post请求

仰望天空，脚踏实地！

在上面两讲中学习了OkHttp的使用，OkHttp还是很强大的。

OkHttp下载文件并带进度条

OkHttp上传文件到服务器并带进度

而本人更喜欢Retrofit+OkHttp结合来实现网络请求，Retrofit使用注解，更加清晰与明了。下面用Retrofit实现简单的Get与Post请求。

一、服务器端

新建OkHttpServer服务器项目，Tomcat服务器具体配置可以参考搭建本地Tomcat服务器及相关配置 。在项目下新建PostAndGetServlet：最后启动服务器。

@WebServlet("/PostAndGetServlet")public class PostAndGetServlet extends HttpServlet {    private static final long serialVersionUID = 1L;    /**     * @see HttpServlet#HttpServlet()     */    public PostAndGetServlet() {        super();        // TODO Auto-generated constructor stub    }    /**     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)     */    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {        System.out.println("doGet");        String userName = request.getParameter("username");        String password = request.getParameter("password");        System.out.println("userName=="+userName+"==password=="+password);        response.setCharacterEncoding("UTF-8");        PrintWriter writer = response.getWriter();        writer.print("Get收到信息");    }    /**     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)     */    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {        System.out.println("doPost");        String userName = request.getParameter("username");        String password = request.getParameter("password");        System.out.println("userName=="+userName+"==password=="+password);        try {            Thread.sleep(5000);        } catch (InterruptedException e) {            // TODO Auto-generated catch block            e.printStackTrace();        }        response.setCharacterEncoding("UTF-8");        PrintWriter writer = response.getWriter();        writer.print("Post收到信息");    }}

二、Android端

1.build.gradle引入相应的jar包

  compile fileTree(dir: 'libs', include: ['*.jar'])    compile 'com.android.support:appcompat-v7:24.1.1'    testCompile 'junit:junit:4.12'    compile files('libs/gson-2.4.jar')    compile 'com.squareup.retrofit2:converter-gson:2.1.0'    compile 'com.squareup.retrofit2:retrofit:2.1.0'    compile 'com.squareup.retrofit2:converter-scalars:2.0.0'    compile 'io.reactivex:rxjava:1.1.0'    compile 'io.reactivex:rxandroid:1.1.0'    compile 'com.squareup.retrofit2:adapter-rxjava:2.0.0-beta4'

2.在layout文件中增加两个按钮：

   <Button        android:id="@+id/refrofit_get"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:text="GET_TEST" />    <Button        android:id="@+id/refrofit_post"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:text="POST_TEST" />

在Activity中实例化两个按钮，并设置点击事件。代码就不贴了。

3.新建RetrofitUtil类，编写以下两个方法：

public class RetrofitUtil {//电脑端cmd输入ipconfig获取ip   public static String baseUrl = "http://192.168.0.100:8080/OkHttpServer/";   public static  Retrofit.Builder retrofitBuilder = new Retrofit.Builder()           .addCallAdapterFactory(RxJavaCallAdapterFactory.create())    //返回string类型，如果返回的是json类型：addConverterFactory(GsonConverterFactory.create())            .addConverterFactory(ScalarsConverterFactory.create())           .baseUrl(baseUrl);    private static OkHttpClient okHttpClient = new OkHttpClient.Builder().connectTimeout(10000, TimeUnit.MILLISECONDS)            .readTimeout(10000,TimeUnit.MILLISECONDS)            .writeTimeout(10000,TimeUnit.MILLISECONDS).build();//get请求    public static void testGet(){        InterfaceRetrofit.GetPetrofit getPetrofit = retrofitBuilder.build().create(InterfaceRetrofit.GetPetrofit.class);        getPetrofit.getTest("xiaohong","123").enqueue(new Callback<String>() {            @Override            public void onResponse(Call<String> call, Response<String> response) {                Log.i("test",response.body().toString());            }            @Override            public void onFailure(Call<String> call, Throwable t) {            }        });    }//post请求    public static void testPost(){        InterfaceRetrofit.PostRetrofit postRetrofit = retrofitBuilder.build().create(InterfaceRetrofit.PostRetrofit.class);        postRetrofit.postTest("xiaoqing","456").enqueue(new Callback<String>() {            @Override            public void onResponse(Call<String> call, Response<String> response) {                Log.i("test",response.body().toString());            }            @Override            public void onFailure(Call<String> call, Throwable t) {            }        });    }}

4.Retrofit的调用是通过接口实现的，上面的get与post请求也是，相应接口如下：

public interface InterfaceRetrofit {    public interface GetPetrofit {        @GET("PostAndGetServlet")        Call<String> getTest(@Query("username") String username, @Query("password") String password);    }    public interface PostRetrofit{        @FormUrlEncoded        @POST("PostAndGetServlet")        Call<String> postTest(@Field("username") String username, @Field("password")String password);    }}

5.为两个按钮添加点击事件，分别添加以上两个方法。最后别忘了相应的权限：

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

6.Android 端相关log：

07-03 20:41:07.772 25048-25048/com.huang.retrofit I/test: Get收到信息07-03 20:41:16.952 25048-25048/com.huang.retrofit I/test: Post收到信息

服务器端log：