SpringBoot中如何进行全局异常处理方式

@Log4j2  
@RestControllerAdvice  
public class GlobalExceptionHandler extends ResponseEntityExceptionHandler {  

    /**  
     * 定义要捕获的异常 可以多个 @ExceptionHandler({})     *  
     * @param request  request  
     * @param e        exception  
     * @param response response  
     * @return 响应结果  
     */  
    @ExceptionHandler(AuroraRuntimeException.class)  
    public GenericResponse customExceptionHandler(HttpServletRequest request, final Exception e, HttpServletResponse response) {  
        AuroraRuntimeException exception = (AuroraRuntimeException) e;  

       if (exception.getCode() == ResponseCode.USER_INPUT_ERROR) {  
           response.setStatus(HttpStatus.BAD_REQUEST.value());  
       } else if (exception.getCode() == ResponseCode.FORBIDDEN) {  
           response.setStatus(HttpStatus.FORBIDDEN.value());  
       } else {  
           response.setStatus(HttpStatus.INTERNAL_SERVER_ERROR.value());  
       }  

        return new GenericResponse(exception.getCode(), null, exception.getMessage());  
    }  

    @ExceptionHandler(NotLoginException.class)  
    public GenericResponse tokenExceptionHandler(HttpServletRequest request, final Exception e, HttpServletResponse response) {  
        log.error("token exception", e);  
        response.setStatus(HttpStatus.FORBIDDEN.value());  
        return new GenericResponse(ResponseCode.AUTHENTICATION_NEEDED);  
    }  

}

@Getter  
public enum ResponseCode {  

    SUCCESS(0, "Success"),  

    INTERNAL_ERROR(1, "服务器内部错误"),  

    USER_INPUT_ERROR(2, "用户输入错误"),  

    AUTHENTICATION_NEEDED(3, "Token过期或无效"),  

    FORBIDDEN(4, "禁止访问"),  

    TOO_FREQUENT_VISIT(5, "访问太频繁，请休息一会儿");  

    private final int code;  

    private final String message;  

    private final Response.Status status;  

    ResponseCode(int code, String message, Response.Status status) {  
        this.code = code;  
        this.message = message;  
        this.status = status;  
    }  

    ResponseCode(int code, String message) {  
        this(code, message, Response.Status.INTERNAL_SERVER_ERROR);  
    }  

}

@Getter  
public class AuroraRuntimeException extends RuntimeException {  

    private final ResponseCode code;  

    public AuroraRuntimeException() {  
        super(String.format("%s", ResponseCode.INTERNAL_ERROR.getMessage()));  
        this.code = ResponseCode.INTERNAL_ERROR;  
    }  

    public AuroraRuntimeException(Throwable e) {  
        super(e);  
        this.code = ResponseCode.INTERNAL_ERROR;  
    }  

    public AuroraRuntimeException(String msg) {  
        this(ResponseCode.INTERNAL_ERROR, msg);  
    }  

    public AuroraRuntimeException(ResponseCode code) {  
        super(String.format("%s", code.getMessage()));  
        this.code = code;  
    }  

    public AuroraRuntimeException(ResponseCode code, String msg) {  
        super(msg);  
        this.code = code;  
    }  

}

@Getter  
@Setter  
public class GenericResponse<T> {  

    private int code;  

    private T data;  

    private String message;  

    public GenericResponse() {};  

    public GenericResponse(int code, T data) {  
        this.code = code;  
        this.data = data;  
    }  

    public GenericResponse(int code, T data, String message) {  
        this(code, data);  
        this.message = message;  
    }  

    public GenericResponse(ResponseCode responseCode) {  
        this.code = responseCode.getCode();  
        this.data = null;  
        this.message = responseCode.getMessage();  
    }  

    public GenericResponse(ResponseCode responseCode, T data) {  
        this(responseCode);  
        this.data = data;  
    }  

    public GenericResponse(ResponseCode responseCode, T data, String message) {  
        this(responseCode, data);  
        this.message = message;  
    }  
}

public User getUserInfo(Long userId) {  
    // some logic

    User user = daoFactory.getExtendedUserMapper().selectByPrimaryKey(userId);  
    if (user == null) {  
        throw new AuroraRuntimeException(ResponseCode.USER_INPUT_ERROR, "用户id不存在");  
    }

    // some logic
    ....
}

public class DispatcherServlet extends FrameworkServlet {
    // ......
    protected void initStrategies(ApplicationContext context) {
        initMultipartResolver(context);
        initLocaleResolver(context);
        initThemeResolver(context);
        initHandlerMappings(context);
        initHandlerAdapters(context);

        // 重点关注
        initHandlerExceptionResolvers(context);

        initRequestToViewNameTranslator(context);
        initViewResolvers(context);
        initFlashMapManager(context);
    }
    // ......
}

public class ExceptionHandlerExceptionResolver extends AbstractHandlerMethodExceptionResolver
        implements ApplicationContextAware, InitializingBean {
    // ......
    private void initExceptionHandlerAdviceCache() {
        // ......
        List<ControllerAdviceBean> adviceBeans = ControllerAdviceBean.findAnnotatedBeans(getApplicationContext());
        AnnotationAwareOrderComparator.sort(adviceBeans);

        for (ControllerAdviceBean adviceBean : adviceBeans) {
            ExceptionHandlerMethodResolver resolver = new ExceptionHandlerMethodResolver(adviceBean.getBeanType());
            if (resolver.hasExceptionMappings()) {
                // 找到所有ExceptionHandler标注的方法并保存成一个ExceptionHandlerMethodResolver类型的对象缓存起来
                this.exceptionHandlerAdviceCache.put(adviceBean, resolver);
                if (logger.isInfoEnabled()) {
                    logger.info("Detected @ExceptionHandler methods in " + adviceBean);
                }
            }
            // ......
        }
    }
    // ......
}

public class ExceptionHandlerMethodResolver {
    // ......
    private Method getMappedMethod(Class<? extends Throwable> exceptionType) {
        List<Class<? extends Throwable>> matches = new ArrayList<Class<? extends Throwable>>();
        // 找到所有适用于Controller抛出异常的处理方法,例如Controller抛出的异常
        // 是AuroraRuntimeException(继承自RuntimeException),那么@ExceptionHandler(AuroraRuntimeException.class)和
        // @ExceptionHandler(Exception.class)标注的方法都适用此异常
        for (Class<? extends Throwable> mappedException : this.mappedMethods.keySet()) {
            if (mappedException.isAssignableFrom(exceptionType)) {
                matches.add(mappedException);
            }
        }
        if (!matches.isEmpty()) {
        /* 这里通过排序找到最适用的方法,排序的规则依据抛出异常相对于声明异常的深度,例如
    Controller抛出的异常是是AuroraRuntimeException(继承自RuntimeException),那么AuroraRuntimeException
    相对于@ExceptionHandler(AuroraRuntimeException.class)声明的AuroraRuntimeException.class其深度是0,
    相对于@ExceptionHandler(Exception.class)声明的Exception.class其深度是2,所以
    @ExceptionHandler(BizException.class)标注的方法会排在前面 */
            Collections.sort(matches, new ExceptionDepthComparator(exceptionType));
            return this.mappedMethods.get(matches.get(0));
        }
        else {
            return null;
        }
    }
    // ......
}