Retrofit工具类

import android.util.Log;

import java.io.IOException;
import java.util.HashMap;
import java.util.Map;

import okhttp3.FormBody;
import okhttp3.Interceptor;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.RequestBody;
import okhttp3.Response;
import retrofit2.Retrofit;
import retrofit2.adapter.rxjava2.RxJava2CallAdapterFactory;
import retrofit2.converter.gson.GsonConverterFactory;

public class RetrofitUtil {
    private static RetrofitUtil retrofitUtil = null;
    private Retrofit retrofit;
    private RetrofitUtil() {
    }
    private RetrofitUtil(String baseUrl) {
        OkHttpClient okHttpClient = new OkHttpClient.Builder()
                .addInterceptor(new CommonParamsInterceptor())
                .build();
        retrofit = new Retrofit.Builder()
                .baseUrl(baseUrl)
                .client(okHttpClient)
                .addConverterFactory(GsonConverterFactory.create())
                .addCallAdapterFactory(RxJava2CallAdapterFactory.create())
                .build();
    }
    public static RetrofitUtil getInstance(String baseUrl) {
        if (retrofitUtil == null) {
            synchronized (RetrofitUtil.class) {
                if (retrofitUtil == null) {
                    retrofitUtil = new RetrofitUtil(baseUrl);
                }
            }
        }
        return retrofitUtil;
    }
    public  T createService(Class service) {
        return retrofit.create(service);
    }
    public static ApiService getService() {
        return RetrofitUtil.getInstance(Constant.BASE_URL).createService(ApiService.class);
    }
    private static class CommonParamsInterceptor implements Interceptor {
        @Override
        public Response intercept(Chain chain) throws IOException {
            Request request = chain.request();
            String method = request.method();
            String oldUrl = request.url().toString();
            Log.e("----oldUrl",oldUrl);
            Map map = new HashMap<>();
            map.put("source","android");
            if ("GET".equals(method)){
                StringBuilder stringBuilder = new StringBuilder();
                stringBuilder.append(oldUrl);
                if (oldUrl.contains("?")){
                    if (oldUrl.indexOf("?") == oldUrl.length()-1){
                    }else {
                        stringBuilder.append("&");
                    }
                }else {
                    stringBuilder.append("?");
                }
                for (Map.Entry entry: map.entrySet()) {
                    stringBuilder.append(entry.getKey())
                            .append("=")
                            .append(entry.getValue())
                            .append("&");
                }
                if (stringBuilder.indexOf("&") != -1){
                    stringBuilder.deleteCharAt(stringBuilder.lastIndexOf("&"));
                }
                String newUrl = stringBuilder.toString();
                Log.e("----newUrl",newUrl);
                request = request.newBuilder().url(newUrl).build();
            }else if ("POST".equals(method)){
                RequestBody requestBody = request.body();
                if (requestBody instanceof FormBody){
                    FormBody oldBody = (FormBody) requestBody;
                    FormBody.Builder builder = new FormBody.Builder();
                    for (int i = 0;i entry: map.entrySet()) {
                        builder.add(entry.getKey(),entry.getValue());
                    }
                    request = request.newBuilder().url(oldUrl).post(builder.build()).build();
                }
            }
            Response response = chain.proceed(request);
            return response;
        }
    }
}