让Retrofit直接返回你想要的结果

计划让Retrofit实现这样的效果。

public class Main {

    public static void main(String[] args) {
        GitHubService gitHubService = new Retrofit.Builder()
                .baseUrl("https://api.github.com")
                .addConverterFactory(GsonConverterFactory.create())
                .addCallAdapterFactory(new DirectCallAdapterFactory())
                .build()
                .create(GitHubService.class);
        // 通常情况retrofit的返回值需要是Call<User>类型
        // 如果想要直接返回User，需要做些工作，参见下面的代码
        User user = gitHubService.getUser("jijunpeng");
        System.out.println(user);
    }
}

接口详情参见页面github文档的相关说明 https://developer.github.com/v3/users/

GitHubService 定义github接口

import retrofit2.http.GET;
import retrofit2.http.Path;

/**
 * 一般情况接口的返回值需要写成Call<User>的形式，但是我这里想直接获取User类，就需要做一些工作了
 */
public interface GitHubService {
    /**
     * 获取github用户信息
     */
    @GET("/users/{username}")
    User getUser(@Path("username") String username);
}

User 接受数据类

import com.google.gson.annotations.SerializedName;
import lombok.Data;

/**
 * 从github接口创建出来的类。@Data是lombok的注解，我用来创建get和set方法
 */
@Data
public class User {
    private String login;
    private int id;
    @SerializedName("node_id")
    private String node_id;
    @SerializedName("avatar_url")
    private String avatar_url;
    @SerializedName("gravatar-id")
    private String gravatar_id;
    private String url;
    @SerializedName("html_url")
    private String htmlUrl;
    @SerializedName("followers_url")
    private String followersUrl;
    @SerializedName("following_url")
    private String followingUrl;
    @SerializedName("gists_url")
    private String gistsUrl;
    @SerializedName("starred_url")
    private String starredUrl;
    @SerializedName("subscriptions_url")
    private String subscriptionsUrl;
    @SerializedName("organizations_url")
    private String organizationsUrl;
    @SerializedName("repos_url")
    private String reposUrl;
    @SerializedName("events_url")
    private String eventsUrl;
    @SerializedName("received_events_url")
    private String receivedEventsUrl;
    private String type;
    @SerializedName("site_admin")
    private boolean siteAdmin;
    private String name;
    private String company;
    private String blog;
    private String location;
    private String email;
    private boolean hireable;
    private String bio;
    @SerializedName("public_repos")
    private int publicRepos;
    @SerializedName("public_gists")
    private int publicGists;
    private int followers;
    private int following;
    @SerializedName("created_at")
    private String createdAt;
    @SerializedName("updated_at")
    private String updatedAt;
}

DirectCallAdapterFactory 实现可以直接返回数据类的核心类


import retrofit2.Call;
import retrofit2.CallAdapter;
import retrofit2.Retrofit;

import java.io.IOException;
import java.lang.annotation.Annotation;
import java.lang.reflect.Type;
import java.lang.reflect.WildcardType;

/**
 * 实现可以直接返回数据类的核心类
 */
public class DirectCallAdapterFactory extends CallAdapter.Factory {
    @Override
    public CallAdapter<?, ?> get(Type returnType, Annotation[] annotations, Retrofit retrofit) {
        final Type responseType = getResponseType(returnType);

        return new CallAdapter<Object, Object>() {
            public Type responseType() {
                return responseType;
            }

            public Object adapt(Call<Object> call) {
                // todo 可以在这里判断接口数据格式
                try {
                    return call.execute().body();
                } catch (IOException e) {
                    e.printStackTrace();
                }
                return null;
            }
        };
    }

    private Type getResponseType(Type type) {
        if (type instanceof WildcardType) {
            return ((WildcardType) type).getUpperBounds()[0];
        }
        return type;
    }
}

直接执行 main 方法可以输出一下结果：

User(login=jijunpeng, id=8679345, node_id=MDQ6VXNlcjg2NzkzNDU=, avatar_url=https://avatars0.githubusercontent.com/u/8679345?v=4, gravatar_id=null, url=https://api.github.com/users/jijunpeng, htmlUrl=https://github.com/jijunpeng, followersUrl=https://api.github.com/users/jijunpeng/followers, followingUrl=https://api.github.com/users/jijunpeng/following{/other_user}, gistsUrl=https://api.github.com/users/jijunpeng/gists{/gist_id}, starredUrl=https://api.github.com/users/jijunpeng/starred{/owner}{/repo}, subscriptionsUrl=https://api.github.com/users/jijunpeng/subscriptions, organizationsUrl=https://api.github.com/users/jijunpeng/orgs, reposUrl=https://api.github.com/users/jijunpeng/repos, eventsUrl=https://api.github.com/users/jijunpeng/events{/privacy}, receivedEventsUrl=https://api.github.com/users/jijunpeng/received_events, type=User, siteAdmin=false, name=null, company=null, blog=, location=null, email=null, hireable=false, bio=null, publicRepos=14, publicGists=0, followers=0, following=1, createdAt=2014-09-06T16:07:44Z, updatedAt=2018-12-08T11:07:50Z)

让Retrofit直接返回你想要的结果

让Retrofit直接返回你想要的结果

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