Add Default Exception Handling Template

src/main/java/com/classvar/error/GlobalApiExceptionHandler.java

@@ -0,0 +1,177 @@
+package com.classvar.error;
+
+import static com.classvar.error.exception.util.ErrorResponseUtil.build;
+import static java.util.stream.Collectors.toList;
+
+import com.classvar.error.exception.BusinessException;
+import com.classvar.error.exception.dto.ErrorResponseDto;
+import com.classvar.error.exception.dto.InvalidParameterDto;
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Optional;
+import javax.validation.ConstraintViolationException;
+import javax.validation.Path;
+import javax.validation.Path.Node;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.core.Ordered;
+import org.springframework.core.annotation.Order;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpMethod;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.http.converter.HttpMessageNotReadableException;
+import org.springframework.web.HttpRequestMethodNotSupportedException;
+import org.springframework.web.bind.MethodArgumentNotValidException;
+import org.springframework.web.bind.MissingPathVariableException;
+import org.springframework.web.bind.MissingServletRequestParameterException;
+import org.springframework.web.bind.annotation.ExceptionHandler;
+import org.springframework.web.bind.annotation.RestControllerAdvice;
+import org.springframework.web.context.request.ServletWebRequest;
+import org.springframework.web.context.request.WebRequest;
+import org.springframework.web.servlet.mvc.method.annotation.ResponseEntityExceptionHandler;
+
+@Order(Ordered.HIGHEST_PRECEDENCE)
+@RestControllerAdvice
+@Slf4j
+public class GlobalApiExceptionHandler extends ResponseEntityExceptionHandler {
+
+  @ExceptionHandler(value = {Exception.class})
+  public ResponseEntity<Object> handleUncaughtException(final Exception ex,
+      final ServletWebRequest request) {
+    log(ex, request);
+    final ErrorResponseDto errorResponseDto = build(Exception.class.getSimpleName(),
+        "서버의 문제로 응답에 문제가 발생했습니다.", HttpStatus.INTERNAL_SERVER_ERROR);
+    return ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR).body(errorResponseDto);
+  }
+
+  @ExceptionHandler({BusinessException.class})
+  public ResponseEntity<Object> handleCustomUncaughtBusinessException(final BusinessException ex,
+      final ServletWebRequest request) {
+    log(ex, request);
+    final ErrorResponseDto errorResponseDto = build(ex.getCode(), ex.getMessage(),
+        ex.getHttpStatus());
+    return ResponseEntity.status(ex.getHttpStatus()).body(errorResponseDto);
+  }
+
+  @ExceptionHandler(value = {ConstraintViolationException.class})
+  public ResponseEntity<Object> handleConstraintViolationException(
+      final ConstraintViolationException ex,
+      final ServletWebRequest request) {
+    log(ex, request);
+
+    final List<InvalidParameterDto> invalidParameters = new ArrayList<>();
+    ex.getConstraintViolations().forEach(constraintViolation -> {
+      final Iterator<Node> it = constraintViolation.getPropertyPath().iterator();
+      if (it.hasNext()) {
+        try {
+          it.next();
+          final Path.Node n = it.next();
+          final InvalidParameterDto invalidParameter = new InvalidParameterDto();
+          invalidParameter.setParameter(n.getName());
+          invalidParameter.setMessage(constraintViolation.getMessage());
+          invalidParameters.add(invalidParameter);
+        } catch (final Exception e) {
+          log.warn("Can't extract the information about constraint violation");
+        }
+      }
+    });
+
+    final ErrorResponseDto errorResponseDto = build(
+        ConstraintViolationException.class.getSimpleName(),
+        HttpStatus.BAD_REQUEST.getReasonPhrase(), HttpStatus.BAD_REQUEST, invalidParameters);
+
+    return ResponseEntity.status(HttpStatus.BAD_REQUEST).body(errorResponseDto);
+  }
+
+  //메시지 컨버터에서 변환할 수 없는 경우
+  @Override
+  protected ResponseEntity<Object> handleHttpMessageNotReadable(
+      final HttpMessageNotReadableException ex,
+      final HttpHeaders headers, final HttpStatus status, final WebRequest request) {
+    log(ex, (ServletWebRequest) request);
+    final ErrorResponseDto errorResponseDto = build(
+        HttpMessageNotReadableException.class.getSimpleName(), ex.getMessage(),
+        HttpStatus.BAD_REQUEST);
+    return ResponseEntity.status(HttpStatus.BAD_REQUEST).body(errorResponseDto);
+  }
+
+  @Override
+  protected ResponseEntity<Object> handleHttpRequestMethodNotSupported(
+      final HttpRequestMethodNotSupportedException ex, final HttpHeaders headers,
+      final HttpStatus status,
+      final WebRequest request) {
+    log(ex, (ServletWebRequest) request);
+    final ErrorResponseDto errorResponseDto = build(
+        HttpRequestMethodNotSupportedException.class.getSimpleName(), ex.getMessage(),
+        HttpStatus.METHOD_NOT_ALLOWED);
+    return ResponseEntity.status(HttpStatus.METHOD_NOT_ALLOWED).body(errorResponseDto);
+  }
+
+  @Override
+  protected ResponseEntity<Object> handleMethodArgumentNotValid(
+      final MethodArgumentNotValidException ex,
+      final HttpHeaders headers, final HttpStatus status, final WebRequest request) {
+    log(ex, (ServletWebRequest) request);
+    final List<InvalidParameterDto> invalidParameters = ex.getBindingResult().getFieldErrors()
+        .stream()
+        .map(fieldError -> InvalidParameterDto.builder()
+            .parameter(fieldError.getField())
+            .message(fieldError.getDefaultMessage())
+            .build()).collect(toList());
+
+    final ErrorResponseDto errorResponseDto = build(
+        MethodArgumentNotValidException.class.getSimpleName(),
+        HttpStatus.BAD_REQUEST.getReasonPhrase(), HttpStatus.BAD_REQUEST, invalidParameters);
+
+    return ResponseEntity.status(HttpStatus.BAD_REQUEST).body(errorResponseDto);
+  }
+
+  @Override
+  protected ResponseEntity<Object> handleMissingPathVariable(final MissingPathVariableException ex,
+      final HttpHeaders headers, final HttpStatus status, final WebRequest request) {
+    final ErrorResponseDto errorResponseDto = build(
+        MissingPathVariableException.class.getSimpleName(),
+        HttpStatus.BAD_REQUEST.getReasonPhrase(), HttpStatus.BAD_REQUEST);
+    return ResponseEntity.status(HttpStatus.BAD_REQUEST).body(errorResponseDto);
+  }
+
+  @Override
+  protected ResponseEntity<Object> handleMissingServletRequestParameter(
+      final MissingServletRequestParameterException ex, final HttpHeaders headers,
+      final HttpStatus status,
+      final WebRequest request) {
+    log(ex, (ServletWebRequest) request);
+    final ErrorResponseDto errorResponseDto = build(
+        MissingServletRequestParameterException.class.getSimpleName(),
+        HttpStatus.BAD_REQUEST.getReasonPhrase(), HttpStatus.BAD_REQUEST);
+    return ResponseEntity.status(HttpStatus.BAD_REQUEST).body(errorResponseDto);
+  }
+
+  private void log(final Exception ex, final ServletWebRequest request) {
+    final Optional<HttpMethod> httpMethod;
+    final Optional<String> requestUrl;
+
+    final Optional<ServletWebRequest> possibleIncomingNullRequest = Optional.ofNullable(request);
+    if (possibleIncomingNullRequest.isPresent()) {
+      // get the HTTP Method
+      httpMethod = Optional.ofNullable(possibleIncomingNullRequest.get().getHttpMethod());
+      if (Optional.ofNullable(possibleIncomingNullRequest.get().getRequest()).isPresent()) {
+        // get the Request URL
+        requestUrl = Optional.of(
+            possibleIncomingNullRequest.get().getRequest().getRequestURL().toString());
+      } else {
+        requestUrl = Optional.empty();
+      }
+    } else {
+      httpMethod = Optional.empty();
+      requestUrl = Optional.empty();
+    }
+
+    log.error("Request {} {} failed with exception reason: {}",
+        (httpMethod.isPresent() ? httpMethod.get() : "'null'"),
+        (requestUrl.orElse("'null'")), ex.getMessage(), ex);
+  }
+
+
+}

src/main/java/com/classvar/error/exception/BusinessException.java

@@ -0,0 +1,47 @@
+package com.classvar.error.exception;
+
+import com.classvar.error.exception.policy.BusinessExceptionPolicy;
+import lombok.Getter;
+import org.springframework.http.HttpStatus;
+
+@Getter
+public class BusinessException extends RuntimeException implements BusinessExceptionPolicy {
+
+  protected final String code;
+  protected final String message;
+  protected final HttpStatus httpStatus;
+
+  public BusinessException(final BusinessExceptionReason reason) {
+    this.code = reason.getCode();
+    this.message = reason.getMessage();
+    this.httpStatus = reason.getHttpStatus();
+  }
+
+  public BusinessException(final BusinessExceptionReason reason,
+      final HttpStatus overridingHttpStatus) {
+    this.code = reason.getCode();
+    this.message = reason.getMessage();
+    this.httpStatus = overridingHttpStatus;
+  }
+
+  public BusinessException(final BusinessExceptionReason reason, final Object... parameters) {
+    if (parameters != null) {
+      this.message = String.format(reason.getMessage(), parameters);
+    } else {
+      this.message = reason.getMessage();
+    }
+    this.code = reason.getCode();
+    this.httpStatus = reason.getHttpStatus();
+  }
+
+  @Override
+  public String getLocalizedMessage() {
+    return getMessage();
+  }
+
+  public String toString() {
+    return String.format("BusinessException(code=%s, message=%s, httpStatus=%s)", this.getCode(),
+        this.getMessage(),
+        this.getHttpStatus().value());
+  }
+}

src/main/java/com/classvar/error/exception/BusinessExceptionReason.java

@@ -0,0 +1,16 @@
+package com.classvar.error.exception;
+
+import com.classvar.error.exception.policy.BusinessExceptionPolicy;
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+import org.springframework.http.HttpStatus;
+
+@Getter
+@AllArgsConstructor
+public enum BusinessExceptionReason implements BusinessExceptionPolicy {
+  NO_SUCH_ID("No such id: %s", HttpStatus.BAD_REQUEST);
+
+  private final String code = BusinessExceptionReason.class.getSimpleName();
+  private final String message;
+  private final HttpStatus httpStatus;
+}

src/main/java/com/classvar/error/exception/dto/ErrorResponseDto.java

@@ -0,0 +1,20 @@
+package com.classvar.error.exception.dto;
+
+import java.time.LocalDateTime;
+import java.util.List;
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+
+@NoArgsConstructor
+@AllArgsConstructor
+@Getter
+public class ErrorResponseDto {
+
+  private String code;
+  private String message;
+  private Integer status;
+  private LocalDateTime timestamp;
+  private List<InvalidParameterDto> invalidParameters;
+
+}

src/main/java/com/classvar/error/exception/dto/InvalidParameterDto.java

@@ -0,0 +1,19 @@
+package com.classvar.error.exception.dto;
+
+import lombok.AllArgsConstructor;
+import lombok.Builder;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+import lombok.Setter;
+
+@NoArgsConstructor
+@AllArgsConstructor
+@Getter
+@Setter
+@Builder
+public class InvalidParameterDto {
+
+  private String parameter;
+  private String message;
+
+}

src/main/java/com/classvar/error/exception/policy/BusinessExceptionPolicy.java

@@ -0,0 +1,7 @@
+package com.classvar.error.exception.policy;
+
+import org.springframework.http.HttpStatus;
+
+public interface BusinessExceptionPolicy extends ExceptionPolicy{
+  HttpStatus getHttpStatus();
+}

src/main/java/com/classvar/error/exception/policy/ExceptionPolicy.java

@@ -0,0 +1,6 @@
+package com.classvar.error.exception.policy;
+
+public interface ExceptionPolicy {
+  String getCode();
+  String getMessage();
+}

src/main/java/com/classvar/error/exception/util/ErrorResponseUtil.java

@@ -0,0 +1,47 @@
+package com.classvar.error.exception.util;
+
+import com.classvar.error.exception.dto.ErrorResponseDto;
+import com.classvar.error.exception.dto.InvalidParameterDto;
+import java.time.LocalDateTime;
+import java.util.ArrayList;
+import java.util.List;
+import org.springframework.http.HttpStatus;
+import org.springframework.util.CollectionUtils;
+
+public final class ErrorResponseUtil {
+
+  private ErrorResponseUtil() {
+  }
+
+  public static ErrorResponseDto build(final String code, final String message,
+      final HttpStatus status) {
+    return buildDetails(code, message, status);
+  }
+
+  public static ErrorResponseDto build(final String code, final String message,
+      final HttpStatus status,
+      final List<InvalidParameterDto> invalidParameters) {
+    return buildDetails(code, message, status, invalidParameters);
+  }
+
+  private static ErrorResponseDto buildDetails(final String code, final String message,
+      final HttpStatus status) {
+    ErrorResponseDto errorResponseDto = new ErrorResponseDto(code, message, status.value(),
+        LocalDateTime.now(), new ArrayList<>());
+    return errorResponseDto;
+  }
+
+  private static ErrorResponseDto buildDetails(final String code, final String message,
+      final HttpStatus status,
+      final List<InvalidParameterDto> invalidParameters) {
+    ErrorResponseDto errorResponseDetails = new ErrorResponseDto(code, message,
+        status.value(), LocalDateTime.now(), new ArrayList<>());
+
+    if (!CollectionUtils.isEmpty(invalidParameters)) {
+      errorResponseDetails = new ErrorResponseDto(code, message,
+          status.value(), LocalDateTime.now(), invalidParameters);
+    }
+    return errorResponseDetails;
+  }
+
+}