6주차 과제 - 로그인 구현하기

app/src/main/java/com/codesoom/assignment/application/AuthenticationService.java

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+package com.codesoom.assignment.application;
+
+import com.codesoom.assignment.utils.JwtUtil;
+import io.jsonwebtoken.Claims;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.stereotype.Service;
+
+@Service
+@Slf4j
+public class AuthenticationService {
+
+    private final JwtUtil jwtUtil;
+
+    public AuthenticationService(JwtUtil jwtUtil) {
+        this.jwtUtil = jwtUtil;
+    }
+
+    public String login(){
+        return jwtUtil.encode(1L);
+    }
+
+    public Claims parseToken(String token) {
+        return jwtUtil.decode(token);
+    }
+}

app/src/main/java/com/codesoom/assignment/errors/InvalidTokenException.java

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+package com.codesoom.assignment.errors;
+
+public class InvalidTokenException extends RuntimeException {
+    public InvalidTokenException(String token) {
+        super("Invalid token : " + token);
+    }
+}

app/src/main/java/com/codesoom/assignment/utils/JwtUtil.java

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+package com.codesoom.assignment.utils;
+
+import com.codesoom.assignment.errors.InvalidTokenException;
+import io.jsonwebtoken.Claims;
+import io.jsonwebtoken.Jws;
+import io.jsonwebtoken.Jwts;
+import io.jsonwebtoken.security.Keys;
+import io.jsonwebtoken.security.SignatureException;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.stereotype.Component;
+
+import java.security.Key;
+
+@Component
+public class JwtUtil {
+
+    private final Key key;
+
+    public JwtUtil(@Value("${jwt.secret}") String secret){
+        key = Keys.hmacShaKeyFor(secret.getBytes());
+    }
+
+    public String encode(Long userId){
+        return Jwts.builder()
+                .claim("userId" , userId)
+                .signWith(key)
+                .compact();
+    }
+
+    public Claims decode(String token) {
+        if(token == null || token.isBlank()){
+            throw new InvalidTokenException(token);
+        }
+        try{
+            return Jwts.parserBuilder()
+                    .setSigningKey(key)
+                    .build()
+                    .parseClaimsJws(token)
+                    .getBody();
+        }catch(SignatureException e){
+            throw new InvalidTokenException(token);
+        }
+
+    }
+}

app/src/test/java/com/codesoom/assignment/applcation/AuthenticationServiceTest.java

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+package com.codesoom.assignment.applcation;
+
+import com.codesoom.assignment.application.AuthenticationService;
+import com.codesoom.assignment.utils.JwtUtil;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Nested;
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.*;
+
+class AuthenticationServiceTest {
+
+    private AuthenticationService service;
+    private final String SECRET = "12345678901234567890123456789012";
+
+    @BeforeEach
+    void setUp() {
+        JwtUtil jwtUtil = new JwtUtil(SECRET);
+        service = new AuthenticationService(jwtUtil);
+    }
+
+    @Nested
+    @DisplayName("")
+    class Describe_{
+
+        @Nested
+        @DisplayName("")
+        class Context_{
+
+            @Test
+            @DisplayName("")
+            void It_(){
+                String accessToken = service.login();
+
+                assertThat(accessToken).contains(".xxxx");
+            }
+        }
+    }
+}