互联网并发与安全系列教程（08） - API接口幂等设计与实现

@Component
public class BaseRedisService {
  @Autowired
  private StringRedisTemplate stringRedisTemplate;
  public void setString(String key, Object data, Long timeout) {
    if (data instanceof String) {
      String value = (String) data;
      stringRedisTemplate.opsForValue().set(key, value);
    }
    if (timeout != null) {
      stringRedisTemplate.expire(key, timeout, TimeUnit.SECONDS);
    }
  }
  public Object getString(String key) {
    return stringRedisTemplate.opsForValue().get(key);
  }
  public void delKey(String key) {
    stringRedisTemplate.delete(key);
  }
}

@Component
public class RedisTokenUtils {
  private long timeout = 60 * 60;
  @Autowired
  private BaseRedisService baseRedisService;
  // 将token存入在redis
  public String getToken() {
    String token = "token" + System.currentTimeMillis();
    baseRedisService.setString(token, token, timeout);
    return token;
  }
  public boolean findToken(String tokenKey) {
    String token = (String) baseRedisService.getString(tokenKey);
    if (StringUtils.isEmpty(token)) {
      return false;
    }
    // token 获取成功后 删除对应tokenMapstoken
    baseRedisService.delKey(token);
    return true;
  }
}

@Target(value = ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
public @interface ExtApiIdempotent {
  String value();
}

@Aspect
@Component
public class ExtApiAopIdempotent {
  @Autowired
  private RedisTokenUtils redisTokenUtils;
  @Pointcut("execution(public * com.itmayiedu.controller.*.*(..))")
  public void rlAop() {
  }
  @Around("rlAop()")
  public Object doBefore(ProceedingJoinPoint proceedingJoinPoint) throws Throwable {
    MethodSignature signature = (MethodSignature) proceedingJoinPoint.getSignature();
    ExtApiIdempotent extApiIdempotent = signature.getMethod().getDeclaredAnnotation(ExtApiIdempotent.class);
    if (extApiIdempotent == null) {
      // 直接执行程序
      Object proceed = proceedingJoinPoint.proceed();
      return proceed;
    }
    // 代码步骤：
    // 1.获取令牌 存放在请求头中
    HttpServletRequest request = getRequest();
    String token = request.getHeader("token");
    if (StringUtils.isEmpty(token)) {
      response("参数错误!");
      return null;
    }
    // 2.判断令牌是否在缓存中有对应的令牌
    // 3.如何缓存没有该令牌的话，直接报错（请勿重复提交）
    // 4.如何缓存有该令牌的话，直接执行该业务逻辑
    // 5.执行完业务逻辑之后，直接删除该令牌。
    if (!redisTokenUtils.findToken(token)) {
      response("请勿重复提交!");
      return null;
    }
    Object proceed = proceedingJoinPoint.proceed();
    return proceed;
  }
  public HttpServletRequest getRequest() {
    ServletRequestAttributes attributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
    HttpServletRequest request = attributes.getRequest();
    return request;
  }
  public void response(String msg) throws IOException {
    ServletRequestAttributes attributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
    HttpServletResponse response = attributes.getResponse();
    response.setHeader("Content-type", "text/html;charset=UTF-8");
    PrintWriter writer = response.getWriter();
    try {
      writer.println(msg);
    } catch (Exception e) {
    } finally {
      writer.close();
    }
  }
}

// 从redis中获取Token
@RequestMapping("/redisToken")
public String RedisToken() {
  return redisTokenUtils.getToken();
}
// 验证Token
@RequestMapping(value = "/addOrderExtApiIdempotent", produces = "application/json; charset=utf-8")
@ExtApiIdempotent
public String addOrderExtApiIdempotent(@RequestBody OrderEntity orderEntity, HttpServletRequest request) {
  int result = orderMapper.addOrder(orderEntity);
  return result > 0 ? "添加成功" : "添加失败" + "";
}

@Target(value = ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
public @interface ExtApiToken {
}

@Aspect
@Component
public class ExtApiAopIdempotent {
  @Autowired
  private RedisTokenUtils redisTokenUtils;
  @Pointcut("execution(public * com.itmayiedu.controller.*.*(..))")
  public void rlAop() {
  }
  // 前置通知转发Token参数
  @Before("rlAop()")
  public void before(JoinPoint point) {
    MethodSignature signature = (MethodSignature) point.getSignature();
    ExtApiToken extApiToken = signature.getMethod().getDeclaredAnnotation(ExtApiToken.class);
    if (extApiToken != null) {
      extApiToken();
    }
  }
  // 环绕通知验证参数
  @Around("rlAop()")
  public Object doAround(ProceedingJoinPoint proceedingJoinPoint) throws Throwable {
    MethodSignature signature = (MethodSignature) proceedingJoinPoint.getSignature();
    ExtApiIdempotent extApiIdempotent = signature.getMethod().getDeclaredAnnotation(ExtApiIdempotent.class);
    if (extApiIdempotent != null) {
      return extApiIdempotent(proceedingJoinPoint, signature);
    }
    // 放行
    Object proceed = proceedingJoinPoint.proceed();
    return proceed;
  }
  // 验证Token
  public Object extApiIdempotent(ProceedingJoinPoint proceedingJoinPoint, MethodSignature signature)
      throws Throwable {
    ExtApiIdempotent extApiIdempotent = signature.getMethod().getDeclaredAnnotation(ExtApiIdempotent.class);
    if (extApiIdempotent == null) {
      // 直接执行程序
      Object proceed = proceedingJoinPoint.proceed();
      return proceed;
    }
    // 代码步骤：
    // 1.获取令牌 存放在请求头中
    HttpServletRequest request = getRequest();
    String valueType = extApiIdempotent.value();
    if (StringUtils.isEmpty(valueType)) {
      response("参数错误!");
      return null;
    }
    String token = null;
    if (valueType.equals(ConstantUtils.EXTAPIHEAD)) {
      token = request.getHeader("token");
    } else {
      token = request.getParameter("token");
    }
    if (StringUtils.isEmpty(token)) {
      response("参数错误!");
      return null;
    }
    if (!redisTokenUtils.findToken(token)) {
      response("请勿重复提交!");
      return null;
    }
    Object proceed = proceedingJoinPoint.proceed();
    return proceed;
  }
  public void extApiToken() {
    String token = redisTokenUtils.getToken();
    getRequest().setAttribute("token", token);
  }
  public HttpServletRequest getRequest() {
    ServletRequestAttributes attributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
    HttpServletRequest request = attributes.getRequest();
    return request;
  }
  public void response(String msg) throws IOException {
    ServletRequestAttributes attributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
    HttpServletResponse response = attributes.getResponse();
    response.setHeader("Content-type", "text/html;charset=UTF-8");
    PrintWriter writer = response.getWriter();
    try {
      writer.println(msg);
    } catch (Exception e) {
    } finally {
      writer.close();
    }
  }
}

@RestController
public class OrderController {
  @Autowired
  private OrderMapper orderMapper;
  @Autowired
  private RedisTokenUtils redisTokenUtils;
  // 从redis中获取Token
  @RequestMapping("/redisToken")
  public String RedisToken() {
    return redisTokenUtils.getToken();
  }
  // 验证Token
  @RequestMapping(value = "/addOrderExtApiIdempotent", produces = "application/json; charset=utf-8")
  @ExtApiIdempotent(value = ConstantUtils.EXTAPIHEAD)
  public String addOrderExtApiIdempotent(@RequestBody OrderEntity orderEntity, HttpServletRequest request) {
    int result = orderMapper.addOrder(orderEntity);
    return result > 0 ? "添加成功" : "添加失败" + "";
  }
}

@Controller
public class OrderPageController {
  @Autowired
  private OrderMapper orderMapper;
  @RequestMapping("/indexPage")
  @ExtApiToken
  public String indexPage(HttpServletRequest req) {
    return "indexPage";
  }
  @RequestMapping("/addOrderPage")
  @ExtApiIdempotent(value = ConstantUtils.EXTAPIFROM)
  public String addOrder(OrderEntity orderEntity) {
    int addOrder = orderMapper.addOrder(orderEntity);
    return addOrder > 0 ? "success" : "fail";
  }
}