Java 注解 - 一文就懂，java 程序设计与实践教程王薇
@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
public @interface Log {
String value() default "";
/**
是否启用
*/
boolean enable() default true;
LogActionType type() default LogActionType.SELECT;
}
日志类型
public enum LogActionType {
ADD("新增"),
SELECT("查询"),
UPDATE("更新"),
DELETE("删除");
private String value;
LogActionType(String value) {
this.value = value;
}
public String getValue() {
return value;
}
public void setValue(String value) {
this.value = value;
}
}
定义注解处理器 - 切面
@Component
@Aspect
@Slf4j
public class LogAspect {
// 保存日志信息服务
private final LogService logService;
// 线程隔离，用于计算每个方法的执行时间
ThreadLocal<Long> currentTime = new ThreadLocal<>();
public LogAspect(LogService logService) {
this.logService = logService;
}
/**
配置切入点
该方法无方法体,主要为了让同类中其他方法使用此切入点
*/
@Pointcut("@annotation(com.liziba.annotation.Log)")
public void logPointcut() {
}
/**
配置环绕通知,使用在方法 logPointcut()上注册的切入点
@param joinPoint join point for advice
*/
@Around("logPointcut()")
public Object logAro
und(ProceedingJoinPoint joinPoint) throws Throwable {
Object result;
// 计算方法操作时间
currentTime.set(System.currentTimeMillis());
result = joinPoint.proceed();
Log log = new Log("INFO",System.currentTimeMillis() - currentTime.get());
currentTime.remove();
HttpServletRequest request = RequestHolder.getHttpServletRequest();
// 记录用户名、浏览器信息、ip 地址、切入点、日志信息
logService.save(getUsername(), StringUtils.getBrowser(request), StringUtils.getIp(request),joinPoint, log);
return result;
}
/**
配置异常通知
@param joinPoint join point for advice
@param e exception
*/
@AfterThrowing(pointcut = "logPointcut()", throwing = "e")
public void logAfterThrowing(JoinPoint joinPoint, Throwable e) {
Log log = new Log("ERROR",System.currentTimeMillis() - currentTime.get());
currentTime.remove();
// 获取日志堆栈信息，并设值
log.setExceptionDetail(ThrowableUtil.getStackTrace(e).getBytes());
HttpServletRequest request = RequestHolder.getHttpServletRequest();
// 记录用户名、浏览器信息、ip 地址、切入点、日志信息
logService.save(getUsername(), StringUtils.getBrowser(request), StringUtils.getIp(request), (ProceedingJoinPoint)joinPoint, log);
}
/**
获取用户名信息
*/
public String getUsername() {
try {
return SecurityUtils.getCurrentUsername();
}catch (Exception e){
return "";
}
}
}
4.3 限流注解 - redis+lua 限流
注解定义
@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
public @interface Limit {
// 资源名称，用于描述接口功能
String name() default "";
// 资源 key
String key() default "";
// key prefix
String prefix() default "";
// 时间的，单位秒
int period();
// 限制访问次数
int count();
// 限制类型
LimitType limitType() default LimitType.CUSTOMER;
}
注解类型
public enum LimitType {
// 默认
CUSTOMER,
// IP 限流
IP
}
定义注解处理器 - 切面
@Aspect
@Component
public class LimitAspect {
// redis 用于执行 lua 脚本
private final RedisTemplate<Object,Object> redisTemplate;
private static final Logger logger = LoggerFactory.getLogger(LimitAspect.class);
public LimitAspect(RedisTemplate<Object,Object> redisTemplate) {
this.redisTemplate = redisTemplate;
}
/**
配置切入点
该方法无方法体,主要为了让同类中其他方法使用此切入点
*/
@Pointcut("@annotation(com.liziba.annotation.Limit)")
public void pointcut() {
}
@Around("pointcut()")
public Object around(ProceedingJoinPoint joinPoint) throws Throwable {
HttpServletRequest request = RequestHolder.getHttpServletRequest();
// 获取方法的 Limit 注解
MethodSignature signature = (MethodSignature) joinPoint.getSignature();
Method signatureMethod = signature.getMethod();
Limit limit = signatureMethod.getAnnotation(Limit.class);
LimitType limitType = limit.limitType();
String key = limit.key();
if (StringUtils.isEmpty(key)) {
if (limitType == LimitType.IP) {
key = StringUtils.getIp(request);
} else {
key = signatureMethod.getName();
}
}
// 通过方法或者 ip 结合资源请求路径定义限流 key
ImmutableList<Object> keys = ImmutableList.of(StringUtils.join(limit.prefix(), "", key, "", request.getRequestURI().replaceAll("/","_")));
// Lua 限流脚本
String luaScript = buildLuaScript();
RedisScript<Number> redisScript = new DefaultRedisScript<>(luaScript, Number.class);
// Redis 执行 Lua 脚本
Number count = redisTemplate.execute(redisScript, keys, limit.count(), limit.period());
// 判断是否超过访问次数
if (null != count && count.intValue() <= limit.count()) {
logger.info("第{}次访问 key 为 {}，描述为 [{}] 的接口", count, keys, limit.name());
return joinPoint.proceed();
} else {
throw new BadRequestException("访问次数受限制");
}
}
/**
Lua 限流脚本
*/
private String buildLuaScript() {
return "local c" +
"\nc = redis.call('get',KEYS[1])" +
"\nif c and tonumber(c) > tonumber(ARGV[1]) then" +
"\nreturn c;" +
"\nend" +
"\nc = redis.call('incr',KEYS[1])" +
"\nif tonumber(c) == 1 then" +
"\nredis.call('expire',KEYS[1],ARGV[2])" +
"\nend" +
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