Difference between passing values to URL in Android Retrofit library

Question

I have tried two type of value passing to an URL in Android Retrofit library, method 1 is executed without any error but method 2 throw error.

I sent parameter values by query key name with the value of the annotated parameter in Method 1 and variable substitution for the API endpoint in Method 2

Error thrown by method 2:

java.lang.IllegalArgumentException: URL query string "appid={apikey}&lat={lat}&lon={lon}&units={units}" must not have replace block. For dynamic query parameters use @Query.

My URL : data/2.5/weather?lat=77.603287&lon=12.97623&appid=f5138&units=metric

Method 1: (Executed well)

@GET("data/2.5/weather")
Call<Weather> getWeatherReport(@Query("lat") String lat,
                               @Query("lon") String lng,
                               @Query("appid") String appid,
                               @Query("units") String units);

Method 2: (Error)

@GET("data/2.5/weather?appid={apikey}&lat={lat}&lon={lon}&units={units}")
Call<Weather> getWeatherReport1(@Query("apikey") String apikey,
                               @Query("lat") String lat,
                               @Query("lon") String lng,
                               @Query("units") String units);

I have tried @Path as well as in the second method.

My Questions are 1.What is the difference between both the methods? 2.Why does the second method did not worked?

Answer 1

Second method won't work because

URL query string must not have replace block. For dynamic query parameters use @Query

So also using @Path annotation in that case won't work. You can dynamically assign query parameters by using @Query annotation like in first method. You can dynamically apply only Path parameters with use of @Path annotation like

@GET("data/{version}/")
Call<Weather> getWeatherReport1(@Path("version") String version);