java.lang.IllegalArgumentException：URL“https:/my url/api/login/”不包含“{username}”。 （参数#1）

Question

I am new in android studio, and i am doing login activity using java, retrofit and web api (django restframework). i am getting this error, java.lang.IllegalArgumentException: URL "https:// my url /api/login/" does not contain "{username}". (parameter #1) for method UserService.login , why i am getting this error? eventhough my web api is working?

this is my post data

this is my LoginActivity.java

public class LoginActivity extends AppCompatActivity {
    EditText edtUsername;
    EditText edtPassword;
    Button btnLogin;
    UserService userService;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_login);

        edtUsername = (EditText) findViewById(R.id.edtUsername);
        edtPassword = (EditText) findViewById(R.id.edtPassword);
        btnLogin = (Button) findViewById(R.id.btnLogin);
        userService = ApiUtils.getUserService();

        btnLogin.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String username = edtUsername.getText().toString();
                String password = edtPassword.getText().toString();
                //validate form
                if(validateLogin(username, password)){
                    //do login
                    doLogin(username, password);
                }
            }
        });

    }

    private boolean validateLogin(String username, String password){
        if(username == null || username.trim().length() == 0){
            Toast.makeText(this, "Username is required", Toast.LENGTH_SHORT).show();
            return false;
        }
        if(password == null || password.trim().length() == 0){
            Toast.makeText(this, "Password is required", Toast.LENGTH_SHORT).show();
            return false;
        }
        return true;
    }

    private void doLogin(final String username,final String password){
        Call call = userService.login(username,password);
        call.enqueue(new Callback() {
            @Override
            public void onResponse(Call call, Response response) {
                if(response.isSuccessful()){
                    ResObj resObj = (ResObj) response.body();
                    if(resObj.getMessage().equals("true")){
                        //login start main activity
                        Intent intent = new Intent(LoginActivity.this, DestinationListActivity.class);
                        intent.putExtra("username", username);
                        startActivity(intent);

                    } else {
                        Toast.makeText(LoginActivity.this, "The username or password is incorrect", Toast.LENGTH_SHORT).show();
                    }
                } else {
                    Toast.makeText(LoginActivity.this, "Error! Please try again!", Toast.LENGTH_SHORT).show();
                }
            }

            @Override
            public void onFailure(Call call, Throwable t) {
                Toast.makeText(LoginActivity.this, t.getMessage(), Toast.LENGTH_SHORT).show();
            }
        });
    }
}

my UserService

public interface UserService {
    @POST("https:// my url /api/login/")
    Call login(@Path("username") String username, @Path("password") String password);

}

this is my RetrofitClient

public class RetrofitClient {
    private static Retrofit retrofit = null;

    public static Retrofit getClient(String url){
        if(retrofit == null){
            retrofit = new Retrofit.Builder()
                    .baseUrl(url)
                    .addConverterFactory(GsonConverterFactory.create())
                    .build();
        }
        return retrofit;
    }
}

my ResObj

public class ResObj {
    private String message;

    public String getMessage() {
        return message;
    }

    public void setMessage(String message) {
        this.message = message;
    }
}

my ApiUtils

public class ApiUtils {

    public static final String BASE_URL = "https:// my url /";

    public static UserService getUserService(){
        return RetrofitClient.getClient(BASE_URL).create(UserService.class);
    }
}

this is my full error I receive

E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.smartherd.globofly, PID: 27242
    java.lang.IllegalArgumentException: URL "https:// my url /api/login/" does not contain "{username}". (parameter #1)
        for method UserService.login
        at retrofit2.Utils.methodError(Utils.java:52)
        at retrofit2.Utils.methodError(Utils.java:42)
        at retrofit2.Utils.parameterError(Utils.java:61)
        at retrofit2.RequestFactory$Builder.validatePathName(RequestFactory.java:732)
        at retrofit2.RequestFactory$Builder.parseParameterAnnotation(RequestFactory.java:375)
        at retrofit2.RequestFactory$Builder.parseParameter(RequestFactory.java:295)
        at retrofit2.RequestFactory$Builder.build(RequestFactory.java:182)
        at retrofit2.RequestFactory.parseAnnotations(RequestFactory.java:65)
        at retrofit2.ServiceMethod.parseAnnotations(ServiceMethod.java:25)
        at retrofit2.Retrofit.loadServiceMethod(Retrofit.java:168)
        at retrofit2.Retrofit$1.invoke(Retrofit.java:147)
        at java.lang.reflect.Proxy.invoke(Proxy.java:1006)
        at $Proxy3.login(Unknown Source)
        at com.smartherd.globofly.activities.LoginActivity.doLogin(LoginActivity.java:64)
        at com.smartherd.globofly.activities.LoginActivity.access$100(LoginActivity.java:20)
        at com.smartherd.globofly.activities.LoginActivity$1.onClick(LoginActivity.java:44)
        at android.view.View.performClick(View.java:7125)
        at android.view.View.performClickInternal(View.java:7102)
        at android.view.View.access$3500(View.java:801)
        at android.view.View$PerformClick.run(View.java:27336)
        at android.os.Handler.handleCallback(Handler.java:883)
        at android.os.Handler.dispatchMessage(Handler.java:100)
        at android.os.Looper.loop(Looper.java:214)
        at android.app.ActivityThread.main(ActivityThread.java:7356)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930)
I/Process: Sending signal. PID: 27242 SIG: 9

Answer 1

Update

For @POST type of requests, you can also use @Field to pass individual fields of form-encoded request.

@FormUrlEncoded
@POST("https://www.url.com/api/login/")
Call login(@Field("username") String username, @Field("password") String password);

Documentation of @Field with examples.

To process the response:

Define a simple class AuthenticationResponse :

public class AuthenticationResponse {
    public String token;
}

And use it as a generic type parameter of your login call:

@FormUrlEncoded
@POST("https://www.url.com/api/login/")
Call<AuthenticationResponse> login(@Field("username") String username, @Field("password") String password);

Using AuthenticationResponse will require an update of your LoginActivity method doLogin :

private void doLogin(final String username, final String password) {
    Call<AuthenticationResponse> call = userService.login(username, password);
    call.enqueue(new Callback() {
        @Override
        public void onResponse(Call call, Response response) {
            if (response.isSuccessful()) {
                AuthenticationResponse authResponse = (AuthenticationResponse) response.body();
                if (!TextUtils.isEmpty(authResponse.token)) {
                    //login start main activity
                    Intent intent = new Intent(LoginActivity.this, DestinationListActivity.class);
                    intent.putExtra("username", username);
                    startActivity(intent);

                } else {
                    Toast.makeText(LoginActivity.this, "The username or password is incorrect", Toast.LENGTH_SHORT).show();
                }
            } else {
                Toast.makeText(LoginActivity.this, "Error! Please try again!", Toast.LENGTH_SHORT).show();
            }
        }

        @Override
        public void onFailure(Call call, Throwable t) {
            Toast.makeText(LoginActivity.this, t.getMessage(), Toast.LENGTH_SHORT).show();
        }
    });
}

---

For @POST type of requests if you need your parameters to be part of the request body then you must annotate those parameters with @Body annotation. But you can you only one @Body annotation as the parameter declared with that annotation will define the whole body of a request.

@POST("https://www.url.com/api/login/")
Call login(@Body Credentials credentials);

Where Credentials is a POJO class:

class Credentials {
    public String username;
    public String password;
}

Documentation of @Body .

Why exactly error happens?

When you use @Path("name") annotation you must provide a placeholder for that path argument in your URL.

Instead of:

@POST("https://www.url.com/api/login/")
Call login(@Path("username") String username, @Path("password") String password);

Your POST call declaration should look like this, so the Retrofit will know where to place these path arguments:

@POST("https://www.url.com/api/login/{username}/{password}")
Call login(@Path("username") String username, @Path("password") String password);

Documentation of @Path with examples.

Answer 2

Is your login http endpoint expecting, that you're sending the login data (username, password) as urlencoded parameters in the body? Then try to modify your UserService interface like this:

public class ResObj {
    private String token;

    public String getToken() {
        return token;
    }

    public void setToken(String token) {
        this.token = token;
    }
}

public interface UserService {
    @FormUrlEncoded
    @POST("https:// my url /api/login/")
    Call<ResObj> login(@Field("username") String username, @Field("password") String password);
}