springboot切面写法

1. 自定义一个注解

@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
@Inherited
@Documented
public @interface PreschoolAuth {
    String value() default "#provinceCode";
}

2. 定义增强

@Component
@Aspect
public class AuthAspect {

    @Pointcut("@annotation(PreschoolAuth)")
    public void authentication(){}

    @Before("authentication()")
    public void judge(JoinPoint joinPoint) {
        // 获取被增强的方法注解的参数
        MethodSignature signature = (MethodSignature) joinPoint.getSignature();
        Method method = signature.getMethod();
        PreschoolAuth auth = method.getAnnotation(PreschoolAuth.class);
        String key = auth.value();

        // 根据注解的参数获得被增强的方法的参数
        Object[] args = joinPoint.getArgs();
        List<String> codes = ParamUtil.parseExpression(key, method, args, List.class);
        if (CollectionUtils.isEmpty(codes)){
            throw new BizException(ErrorCode.PERMISSION_DENIED);
        }
        // 获取区划码
        String code = codes.get(0);

        // 获取请求头
        RequestAttributes requestAttributes = RequestContextHolder.getRequestAttributes();
        ServletRequestAttributes sra = (ServletRequestAttributes)requestAttributes;
        HttpServletRequest request = sra.getRequest();
        String secret = request.getHeader("XXXX");
        if(StringUtils.isBlank(secret)) {
            throw new BizException(ErrorCode.XXXXXX);
        }
        // 做校验  do.......
    
    }
}

3. 在需要增强的方法上使用注解

    @PreschoolAuth(value = "#provinceCode")
    public Object query(String provinceCode,.... ) {

        return ....;
    }

• 工具类

public class ParamUtil {

    public static <T> T parseExpression(String expression, Method method, Object[] args, Class<T> classType) {
        if (StringUtils.isBlank(expression)) {
            return null;
        } else if (!expression.trim().startsWith("#") && !expression.trim().startsWith("$")) {
            return null;
        } else {
            LocalVariableTableParameterNameDiscoverer discoverer = new LocalVariableTableParameterNameDiscoverer();
            String[] paramNames = discoverer.getParameterNames(method);
            if (ArrayUtils.isEmpty(paramNames)) {
                return null;
            } else {
                StandardEvaluationContext context = new StandardEvaluationContext();

                for (int i = 0; i < paramNames.length; ++i) {
                    context.setVariable(paramNames[i], args[i]);
                }
                return (new SpelExpressionParser()).parseExpression(expression).getValue(context, classType);
            }
        }
    }
}