[해결방법] duplicateKeyException

duplicateKeyException

Environment
Language: Java
DB: MySQL

 

오류

Caused by: java.lang.IllegalStateException: Duplicate key 400 BAD_REQUEST (attempted merging values DUPLICATED_EMAIL and NOT_EQUAL_PASSWORD)
	at java.base/java.util.stream.Collectors.duplicateKeyException(Collectors.java:135)
	at java.base/java.util.stream.Collectors.lambda$uniqKeysMapAccumulator$1(Collectors.java:182)

 

 

원인

DUPLICATED_EMAIL(HttpStatus.BAD_REQUEST, "이미 존재하는 이메일 입니다."),
NOT_EQUAL_PASSWORD(HttpStatus.BAD_REQUEST,"입력한 비밀번호가 상이합니다."),

// HttpStatus -> ErrorCode 조회
private static final Map<HttpStatus, ErrorCode> BY_HTTPSTATUS =
        Stream.of(values()).collect(Collectors.toMap(ErrorCode::getHttpStatus, e -> e));

public static Optional<ErrorCode> valueOfHttpStatus(HttpStatus httpStatus){
    return Optional.ofNullable(BY_HTTPSTATUS.get(httpStatus));
}

 

• toMap()
  • If the mapped keys contain duplicates (according to Object.equals(Object)), an IllegalStateException is thrown when the collection operation is performed. If the mapped keys might have duplicates, use toMap(Function, Function, BinaryOperator) instead.
  • HttpStatus로부터 Enum을 조회하려고 할 때, Map을 활용하는데 이 때 key 값(= HttpStatus)이 중복될 경우, duplicate관련 IllegalStateException이 발생할 수 있음

 

해결

// HttpStatus -> ErrorCode 조회
private static final Map<HttpStatus, ErrorCode> BY_HTTPSTATUS =
        Stream.of(values()).collect(Collectors.toMap(ErrorCode::getHttpStatus, e -> e, ((e1, e2) -> e1)));
        // Stream.of(values()).collect(Collectors.toMap(ErrorCode::getHttpStatus, e -> e, ((e1, e2) -> e2)));

public static Optional<ErrorCode> valueOfHttpStatus(HttpStatus httpStatus){
    return Optional.ofNullable(BY_HTTPSTATUS.get(httpStatus));
}

 

• toMap(Function, Function, BinaryOperator)
  • BinaryOperator에서 먼저 put할 데이터를 사용할지 나중에 put한 데이터를 사용할지 추가

 

📚 참고 자료

[Error/Exception] java.lang.IllegalStateException: Duplicate key ‘key로 저장하려는 값’ (attempted merging values ~~)