如何使用retrofit去请求网络

引入:

<pre class="brush:xml;toolbar:false" style="margin: 0.5em 0px; padding: 0.4em 0.6em; line-height: 1.5; border-radius: 8px; background: rgb(248, 248, 248); color: rgb(28, 31, 33); font-size: 16px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">compile 'com.google.code.gson:gson:2.8.0'
compile 'com.squareup.retrofit2:retrofit:2.4.0'
compile 'com.squareup.retrofit2:converter-gson:2.4.0'
</pre>

因为retrofit已经包含了okhttp的库，所以就不要额外引入okhttp了

我们使用retrofit来请求:http://139.199.89.89/api/v1/books这样一个API

<pre class="brush:java;toolbar:false" style="margin: 0.5em 0px; padding: 0.4em 0.6em; line-height: 1.5; border-radius: 8px; background: rgb(248, 248, 248); color: rgb(28, 31, 33); font-size: 16px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">private void useRetrofit() {
Retrofit retrofit = new Retrofit.Builder()
.baseUrl("http://139.199.89.89") //设置网络请求的Url地址
.addConverterFactory(GsonConverterFactory.create()) //设置数据解析器
.build();
BookService service = retrofit.create(BookService.class);
Call<BookResponse> call = service.getResult();

//3.发送请求
call.enqueue(new Callback<BookResponse>() {
    @Override
    public void onResponse(Call<BookResponse> call, Response<BookResponse> response) {
        Log.d(TAG,"<<<<<response="+response);
    }

    @Override
    public void onFailure(Call<BookResponse> call, Throwable t) {

    }
});

}
</pre>

我们要写一个service,叫BookService:

<pre class="brush:java;toolbar:false" style="margin: 0.5em 0px; padding: 0.4em 0.6em; line-height: 1.5; border-radius: 8px; background: rgb(248, 248, 248); color: rgb(28, 31, 33); font-size: 16px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">package com.pic.optimize.http;

import retrofit2.Call;
import retrofit2.http.GET;

public interface BookService {
@GET("/api/v1/books")
Call<BookResponse> getResult();
}
</pre>

然后要写json的解析实体BookResponse:

<pre class="brush:java;toolbar:false" style="margin: 0.5em 0px; padding: 0.4em 0.6em; line-height: 1.5; border-radius: 8px; background: rgb(248, 248, 248); color: rgb(28, 31, 33); font-size: 16px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">import java.util.ArrayList;

public class BookResponse {
public ArrayList<Book> data;
public int status;
public String message;
}
</pre>

然后就在onResponse中就可以得到回调了

我们再写一个添加一本书的post的请求,url是http://139.199.89.89，服务端接收参数是

bookName和bookDescription:

<pre class="brush:java;toolbar:false" style="margin: 0.5em 0px; padding: 0.4em 0.6em; line-height: 1.5; border-radius: 8px; background: rgb(248, 248, 248); color: rgb(28, 31, 33); font-size: 16px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">import retrofit2.Call;
import retrofit2.http.Field;
import retrofit2.http.FormUrlEncoded;
import retrofit2.http.POST;

public interface BookPostService {
@POST("/api/v1/books")
@FormUrlEncoded
Call<BookResponse> getResult(@Field("bookName") String name, @Field("bookDescription") String description);
}
</pre>

<pre class="brush:java;toolbar:false" style="margin: 0.5em 0px; padding: 0.4em 0.6em; line-height: 1.5; border-radius: 8px; background: rgb(248, 248, 248); color: rgb(28, 31, 33); font-size: 16px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">private void useRetrofit() {
Retrofit retrofit = new Retrofit.Builder()
.baseUrl("http://139.199.89.89") //设置网络请求的Url地址
.addConverterFactory(GsonConverterFactory.create()) //设置数据解析器
.build();
BookPostService service = retrofit.create(BookPostService.class);
Call<BookResponse> call = service.getResult(mBookNameEdit.getText().toString(),mDescriptionEdit.getText().toString());

//3.发送请求
call.enqueue(new Callback<BookResponse>() {
    @Override
    public void onResponse(Call<BookResponse> call, Response<BookResponse> response) {
        Log.d(TAG,"<<<<<response="+response);
    }

    @Override
    public void onFailure(Call<BookResponse> call, Throwable t) {

    }
});

}
</pre>