A type-safe HTTP client for Android and Java

官网：Retrofit

Retrofit turns your HTTP API into a Java interface.

public interface GitHubService {   @GET("users/{user}/repos")   Call<List<Repo>> listRepos(@Path("user") String user); 
}

The Retrofit class generates an implementation of the GitHubService interface.

Retrofit retrofit = new Retrofit.Builder()     .baseUrl("https://api.github.com/")     .build(); 
GitHubService service = retrofit.create(GitHubService.class);

Each Call from the created GitHubService can make a synchronous or asynchronous HTTP request to the remote webserver.

Call<List<Repo>> repos = service.listRepos("octocat");

Use annotations to describe the HTTP request:

• URL parameter replacement and query parameter support
• Object conversion to request body (e.g., JSON, protocol buffers)
• Multipart request body and file upload