如何将多个主体相似的Spring异常处理方法简化为一个？

方案一：提取通用构建方法（最直接高效） #

把重复的ErrorDto构建和ResponseEntity返回逻辑抽成私有工具方法，每个异常处理方法只需要传入差异化参数即可：

@ExceptionHandler(value = {ProhibitedScimTypeException.class})
public ResponseEntity<ErrorDto> policyConflict(final ProhibitedScimTypeException exception) {
    return buildErrorResponse(exception, HttpStatus.BAD_REQUEST, "prohibited");
}

@ExceptionHandler(value = {UserAlreadyExistsException.class})
public ResponseEntity<ErrorDto> userNameExistsConflict(final UserAlreadyExistsException exception) {
    return buildErrorResponse(exception, HttpStatus.CONFLICT, "uniqueness");
}

@ExceptionHandler(value = {UserNotFoundException.class})
public ResponseEntity<ErrorDto> userNameNotFoundConflict(final UserNotFoundException exception) {
    return buildErrorResponse(exception, HttpStatus.NOT_FOUND, "prohibited");
}

// 提取的公共工具方法
private ResponseEntity<ErrorDto> buildErrorResponse(Exception exception, HttpStatus httpStatus, String scimType) {
    ErrorDto errorDto = new ErrorDto();
    errorDto.setDetail(exception.getMessage());
    errorDto.setStatus(httpStatus.toString());
    errorDto.setScimType(scimType);
    return new ResponseEntity<>(errorDto, httpStatus);
}

方案二：优化ErrorDto构造逻辑（进一步简化代码） #

如果能修改ErrorDto类，给它添加带参构造器或者Builder模式，能让代码更简洁：

比如给ErrorDto添加构造器：

public class ErrorDto {
    private String detail;
    private String status;
    private String scimType;

    public ErrorDto(String detail, String status, String scimType) {
        this.detail = detail;
        this.status = status;
        this.scimType = scimType;
    }

    // 按需保留getter/setter
}

此时公共工具方法可以简化为：

private ResponseEntity<ErrorDto> buildErrorResponse(Exception exception, HttpStatus httpStatus, String scimType) {
    ErrorDto errorDto = new ErrorDto(exception.getMessage(), httpStatus.toString(), scimType);
    return new ResponseEntity<>(errorDto, httpStatus);
}

方案三：自定义注解+全局处理（适合大量同类异常场景） #

如果后续要新增更多同类型异常，可以用自定义注解绑定异常对应的状态码和scimType，减少重复代码：

首先定义注解：

@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
public @interface ScimError {
    HttpStatus status();
    String scimType();
}

给自定义异常添加注解：

@ScimError(status = HttpStatus.BAD_REQUEST, scimType = "prohibited")
public class ProhibitedScimTypeException extends RuntimeException {
    // 异常逻辑
}

@ScimError(status = HttpStatus.CONFLICT, scimType = "uniqueness")
public class UserAlreadyExistsException extends RuntimeException {
    // 异常逻辑
}

@ScimError(status = HttpStatus.NOT_FOUND, scimType = "prohibited")
public class UserNotFoundException extends RuntimeException {
    // 异常逻辑
}

最后写一个全局异常处理方法：

@ExceptionHandler(value = {RuntimeException.class})
public ResponseEntity<ErrorDto> handleScimExceptions(RuntimeException exception) {
    ScimError scimError = exception.getClass().getAnnotation(ScimError.class);
    if (scimError == null) {
        // 处理未标记注解的异常，或直接抛出
        throw exception;
    }
    ErrorDto errorDto = new ErrorDto(exception.getMessage(), scimError.status().toString(), scimError.scimType());
    return new ResponseEntity<>(errorDto, scimError.status());
}

这个方案的优势是新增异常时只需添加注解，不用编写新的ExceptionHandler方法，扩展性更强。

内容的提问来源于stack exchange，提问作者Jack