안드로이드와 스프링 부트 연동하기
GET으로 서버에서 안드로이드로 데이터 전송 받기
Android Studio
AndroidMenifest에 코드 추가
<application>
android:usesCleartextTraffic="true"
</application>
...
<uses-permission android:name="android.permission.INTERNET"/>
android:usesCleartextTraffic="true": HTTP 연결 허용android.permission.INTERNET: 인터넷 연결 허용
activity_main.xml 코드
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context=".MainActivity">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:text="이름"
android:id="@+id/getName" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:text="나이"
android:id="@+id/getAge"/>
<Button
android:id="@+id/getApiButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:text="Api 받아오기" />
</LinearLayout>
전송 받은 데이터를 저장할 객체 클래스 userDTO.class
public class UserDTO {
private String username;
private int age;
public UserDTO(String username, int age) {
this.username = username;
this.age = age;
}
//Getter
...
//Setter
...
}
HTTP 통신을 위한 Retrofit2 라이브러리 사용하기 위해 app수준 build.gradle에 의존성 추가
implementation 'com.squareup.retrofit2:retrofit:2.9.0'
implementation 'com.squareup.retrofit2:converter-gson:2.9.0'
Retrofit 클래스
public class RetrofitClient {
private static RetrofitClient instance = null;
private static UserRetrofitInterface userRetrofitInterface;
private static String baseUrl = "http://10.0.2.2:8080/";
private RetrofitClient() {
retrofit2.Retrofit retrofit = new retrofit2.Retrofit.Builder()
.baseUrl(baseUrl)
.addConverterFactory(GsonConverterFactory.create())
.build();
userRetrofitInterface = retrofit.create(UserRetrofitInterface.class);
}
public static RetrofitClient getInstance() {
if (instance == null) {
instance = new RetrofitClient();
}
return instance;
}
public static UserRetrofitInterface getUserRetrofitInterface() {
return userRetrofitInterface;
}
}
- baseUrl: 서버가 구동되고 있는 ip주소
- 안드로이드는 localhost:8080 대신 10.0.2.2:8080을 사용해야한다.
- addConverterFactory(GsonConverterFactory.create()): 서버로부터 데이터를 받아와서 원하는 타입으로 데이터를 바꾸기 위해 사용
- baseUrl 뒷부분을 쉽게 처리할 수 있도록 인터페이스 제공
RetrofitInterface
public interface UserRetrofitInterface {
@GET("user")
Call<UserDTO> getUSer();
}
MainActiviy.class
public class MainActivity extends AppCompatActivity {
Button getApiBtn;
UserRetrofitInterface userRetrofitInterface;
Call<UserDTO> call;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
getApiBtn = (Button) findViewById(R.id.getApiButton);
TextView usernameText = (TextView) findViewById(R.id.getName);
TextView userAgeText = (TextView) findViewById(R.id.getAge);
RetrofitClient retrofitClient = RetrofitClient.getInstance();
UserRetrofitInterface userRetrofitInterface = RetrofitClient.getUserRetrofitInterface();
getApiBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
call = userRetrofitInterface.getUSer();
call.clone().enqueue(new Callback<UserDTO>() {
@Override
public void onResponse(Call<UserDTO> call, Response<UserDTO> response) {
if (response.isSuccessful()) {
usernameText.setText(response.body().getUsername());
userAgeText.setText(Integer.toString(response.body().getAge()));
}
}
@Override
public void onFailure(Call<UserDTO> call, Throwable t) {
Log.e("retrofit 연동", "실패");
t.printStackTrace();
}
});
}
});
}
}
Spring boot
User
@Getter
@Setter
public class User {
private String username;
private int age;
public User() {
}
public User(String username, int age) {
this.username = username;
this.age = age;
}
}
ApiTransferController
@Slf4j
@RestController
public class ApiTransferController {
@GetMapping(value = "/user", produces = MediaType.APPLICATION_JSON_VALUE)
@ResponseBody
public User userData() {
User user = new User("hello", 20);
return user;
}
}
localhost:8080/user 요청이 들어오면 User 객체를 HTTP 응답 메시지 Body에 담아 반환하면 안드로이드에서 수신한다.
POST
Android Studio
activity_main.xml 코드에 추가
<EditText
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:gravity="center"
android:hint="나이"
android:id="@+id/setAge"/>
<Button
android:id="@+id/setApiButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:text="Api 전송"/>
RetrofiInterface에 코드 추가
@POST("save-user")
Call<ResponseBody> saveUser(@Body UserDTO jsonUser);
@Body: HTTP Body에 객체를 넣어 전송
MainActivity.class에 코드 추가
public class MainActivity extends AppCompatActivity {
.
.
.
protected void onCreate(Bundle savedInstanceState){
.
.
.
setApiBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
UserDTO userDTo = new UserDTO(setUserName.getText().toString(), Integer.parseInt(setUserAge.getText().toString()));
Gson gson = new Gson();
String userInfo = gson.toJson(userDTo);
Log.e("JSON", userInfo);
Call<ResponseBody> call = userRetrofitInterface.saveUser(userDTo);
call.clone().enqueue(new Callback<ResponseBody>() {
@Override
public void onResponse(Call<ResponseBody> call, Response<ResponseBody> response) {
if (response.isSuccessful()) {
Log.e("POST", "성공");
}
}
@Override
public void onFailure(Call<ResponseBody> call, Throwable t) {
Log.e("POST", "실패");
}
});
}
});
}
}
Spring boot
Controller에 코드 추가
@Slf4j
@RestController
public class ApiTransferController {
.
.
.
@PostMapping("/save-user")
@ResponseBody
public void saveUser(@RequestBody User user) {
log.info("username={}",user.getUsername());
log.info("age={}",user.getAge());
}
}
결과
