自定義注解支援SpEL表達式（動态參數）

1.定義日志注解

@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface SysLog {

    //普通的操作說明
    String value() default "";
    
    //spel表達式的操作說明
    String spelValue() default "";
}      

2.定義spel解析工具類

public class SpelUtil {

    /**
     * 用于SpEL表達式解析.
     */
    private static SpelExpressionParser parser = new SpelExpressionParser();
    /**
     * 用于擷取方法參數定義名字.
     */
    private static DefaultParameterNameDiscoverer nameDiscoverer = new DefaultParameterNameDiscoverer();

    public static String generateKeyBySpEL(String spELString, ProceedingJoinPoint joinPoint) {
        // 通過joinPoint擷取被注解方法
        MethodSignature methodSignature = (MethodSignature) joinPoint.getSignature();
        Method method = methodSignature.getMethod();
        // 使用spring的DefaultParameterNameDiscoverer擷取方法形參名數組
        String[] paramNames = nameDiscoverer.getParameterNames(method);
        // 解析過後的Spring表達式對象
        Expression expression = parser.parseExpression(spELString);
        // spring的表達式上下文對象
        EvaluationContext context = new StandardEvaluationContext();
        // 通過joinPoint擷取被注解方法的形參
        Object[] args = joinPoint.getArgs();
        // 給上下文指派
        for (int i = 0; i < args.length; i++) {
            context.setVariable(paramNames[i], args[i]);
        }
        // 表達式從上下文中計算出實際參數值
        /*如:
            @annotation(key="#student.name")
             method(Student student)
             那麼就可以解析出方法形參的某屬性值，return “xiaoming”;
          */
        return expression.getValue(context).toString();
    }
}      

3.定義切面類

@Aspect
@Component
public class SysLogAspect {
    @Autowired
    private LogService logService;

    @Autowired
    private HttpServletRequest request;

    @Pointcut("@annotation(com.ztri.common.annotation.SysLog)")
    public void logPointCut() {

    }

    @Around("logPointCut()")
    public Object around(ProceedingJoinPoint point) throws Throwable {
        long beginTime = System.currentTimeMillis();
        //執行方法
        Object result = point.proceed();
        //執行時長(毫秒)
        long time = System.currentTimeMillis() - beginTime;

        //儲存日志
        saveSysLog(point, time);

        return result;
    }
    private void saveSysLog(ProceedingJoinPoint joinPoint, long time) {
        MethodSignature signature = (MethodSignature) joinPoint.getSignature();
        Method method = signature.getMethod();

        Log sysLog = new Log();
        sysLog.setTime(time);
        SysLog syslog = method.getAnnotation(SysLog.class);
        if (syslog != null) {
            //注解上的描述
            if (StrUtil.isNotBlank(syslog.value())) {
                sysLog.setOperation(syslog.value());
            }
            if (StrUtil.isNotBlank(syslog.spelValue())) {
                String spelValue = SpelUtil.generateKeyBySpEL(syslog.spelValue(), joinPoint);
                sysLog.setOperation(spelValue);
            }
        }
        //請求的方法名
        String className = joinPoint.getTarget().getClass().getName();
        String methodName = signature.getName();
        sysLog.setMethod(className + "." + methodName + "()");

        //請求的參數
        Object[] args = joinPoint.getArgs();
        try {
            String params = JSONUtil.toJsonStr(args);
            sysLog.setParams(params);
        } catch (Exception e) {

        }

        //設定IP位址
        sysLog.setIp(ServletUtil.getClientIP(request));
        UserAgent ua = UserAgentUtil.parse(request.getHeader("User-Agent"));
        sysLog.setBrowser(ua.getBrowser().toString());

        //儲存系統日志
        logService.create(sysLog);
    }
}      

4.方法上使用日志注解

@ApiOperation("進階搜尋(包含點選1.熱門清單 2.更多跳轉頁面)")
    @PostMapping("searchData")
    @SysLog(spelValue = "'進階搜尋' + #searchVo.keyWord")
    public ResponseEntity<Object> searchData(@RequestBody SearchVo searchVo) throws IOException {
        SearchDto searchDto = searchService.searchData(searchVo);
        return new ResponseEntity<>(searchDto, HttpStatus.OK);
    }

    @ApiOperation("登入授權")
    @PostMapping("/login")
    @SysLog("使用者登入")
    public ResponseEntity<Object> login(@Validated(User.Create.class) @RequestBody LoginUser loginUser) {

        return ResponseEntity.ok(authInfo);
    }