楚州电工考证培训学校,楚州哪家电工学校最好

深圳坪山烘箱检测有效认可证书一、概念幂等性, 通俗的说就是一个接口, 多次发起同一个请求, 必须保证操作只能执行一次

比如:

订单接口, 不能多次创建订单支付接口, 重复支付同一笔订单只能扣一次钱支付宝回调接口, 可能会多次回调, 必须处理重复回调普通表单提交接口, 因为网络超时等原因多次点击提交, 只能成功一次等等二、常见解决方案唯一索引 -- 防止新增脏数据token机制 -- 防止页面重复提交悲观锁 -- 获取数据的时候加锁(锁表或锁行)乐观锁 -- 基于版本号version实现, 在更新数据那一刻校验数据分布式锁 -- redis(jedis、redisson)或zookeeper实现状态机 -- 状态变更, 更新数据时判断状态三、本文实现本文采用第2种方式实现, 即通过redis + token机制实现接口幂等性校验

四、实现思路为需要保证幂等性的每一次请求创建一个唯一标识token, 先获取token, 并将此token存入redis, 请求接口时, 将此token放到header或者作为请求参数请求接口, 后端接口判断redis中是否存在此token:

如果存在, 正常处理业务逻辑, 并从redis中删除此token, 那么, 如果是重复请求, 由于token已被删除, 则不能通过校验, 返回请勿重复操作提示如果不存在, 说明参数不合法或者是重复请求, 返回提示即可五、项目简介springbootredis@ApiIdempotent注解 + 拦截器对请求进行拦截@ControllerAdvice全局异常处理压测工具: jmeter说明:本文重点介绍幂等性核心实现, 关于springboot如何集成redis、ServerResponse、ResponseCode等细枝末节不在本文讨论范围之内, 有兴趣的小伙伴可以查看我的Github项目:

https://github.com/wangzaiplus/springboot/tree/wxw六、代码实现pom

<!-- Redis-Jedis -->

<dependency>

<groupId>redis.clients</groupId>

<artifactId>jedis</artifactId>

<version>2.9.0</version>

</dependency>

<!--lombok 本文用到@Slf4j注解, 也可不引用, 自定义log即可-->

<dependency>

<groupId>org.projectlombok</groupId>

<artifactId>lombok</artifactId>

<version>1.16.10</version>

</dependency>JedisUtil

@Component

@Slf4j

public class JedisUtil {

@Autowired

private JedisPool jedisPool;

private Jedis getJedis() {

return jedisPool.getResource();

}

/**

* 设值

*

* @param key

* @param value

* @return

*/

public String set(String key, String value) {

Jedis jedis = null;

try {

jedis = getJedis();

return jedis.set(key, value);

} catch (Exception e) {

log.error("set key:{} value:{} error", key, value, e);

return null;

} finally {

close(jedis);

}

}

/**

* 设值

*

* @param key

* @param value

* @param expireTime 过期时间, 单位: s

* @return

*/

public String set(String key, String value, int expireTime) {

Jedis jedis = null;

try {

jedis = getJedis();

return jedis.setex(key, expireTime, value);

} catch (Exception e) {

log.error("set key:{} value:{} expireTime:{} error", key, value, expireTime, e);

return null;

} finally {

close(jedis);

}

}

/**

* 取值

*

* @param key

* @return

*/

public String get(String key) {

Jedis jedis = null;

try {

jedis = getJedis();

return jedis.get(key);

} catch (Exception e) {

log.error("get key:{} error", key, e);

return null;

} finally {

close(jedis);

}

}

/**

* 删除key

*

* @param key

* @return

*/

public Long del(String key) {

Jedis jedis = null;

try {

jedis = getJedis();

return jedis.del(key.getBytes());

} catch (Exception e) {

log.error("del key:{} error", key, e);

return null;

} finally {

close(jedis);

}

}

/**

* 判断key是否存在

*

* @param key

* @return

*/

public Boolean exists(String key) {

Jedis jedis = null;

try {

jedis = getJedis();

return jedis.exists(key.getBytes());

} catch (Exception e) {

log.error("exists key:{} error", key, e);

return null;

} finally {

close(jedis);

}

}

/**

* 设值key过期时间

*

* @param key

* @param expireTime 过期时间, 单位: s

* @return

*/

public Long expire(String key, int expireTime) {

Jedis jedis = null;

try {

jedis = getJedis();

return jedis.expire(key.getBytes(), expireTime);

} catch (Exception e) {

log.error("expire key:{} error", key, e);

return null;

} finally {

close(jedis);

}

}

/**

* 获取剩余时间

*

* @param key

* @return

*/

public Long ttl(String key) {

Jedis jedis = null;

try {

jedis = getJedis();

return jedis.ttl(key);

} catch (Exception e) {

log.error("ttl key:{} error", key, e);

return null;

} finally {

close(jedis);

}

}

private void close(Jedis jedis) {

if (null != jedis) {

jedis.close();

}

}

}自定义注解@ApiIdempotent

/**

* 在需要保证 接口幂等性 的Controller的方法上使用此注解

*/

@Target({ElementType.METHOD})

@Retention(RetentionPolicy.RUNTIME)

public @interface ApiIdempotent {

}ApiIdempotentInterceptor拦截器

/**

* 接口幂等性拦截器

*/

public class ApiIdempotentInterceptor implements HandlerInterceptor {

@Autowired

private TokenService tokenService;

@Override

public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) {

if (!(handler instanceof HandlerMethod)) {

return true;

}

HandlerMethod handlerMethod = (HandlerMethod) handler;

Method method = handlerMethod.getMethod();

ApiIdempotent methodAnnotation = method.getAnnotation(ApiIdempotent.class);

if (methodAnnotation != null) {

check(request);// 幂等性校验, 校验通过则放行, 校验失败则抛出异常, 并通过统一异常处理返回友好提示

}

return true;

}

private void check(HttpServletRequest request) {

tokenService.checkToken(request);

}

@Override

public void postHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, ModelAndView modelAndView) throws Exception {

}

@Override

public void afterCompletion(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) throws Exception {

}

}TokenServiceImpl

@Service

public class TokenServiceImpl implements TokenService {

private static final String TOKEN_NAME = "token";

@Autowired

private JedisUtil jedisUtil;

@Override

public ServerResponse createToken() {

String str = RandomUtil.UUID32();

StrBuilder token = new StrBuilder();

token.append(Constant.Redis.TOKEN_PREFIX).append(str);

jedisUtil.set(token.toString(), token.toString(), Constant.Redis.EXPIRE_TIME_MINUTE);

return ServerResponse.success(token.toString());

}

@Override

public void checkToken(HttpServletRequest request) {

String token = request.getHeader(TOKEN_NAME);

if (StringUtils.isBlank(token)) {// header中不存在token

token = request.getParameter(TOKEN_NAME);

if (StringUtils.isBlank(token)) {// parameter中也不存在token

throw new ServiceException(ResponseCode.ILLEGAL_ARGUMENT.getMsg());

}

}

if (!jedisUtil.exists(token)) {

throw new ServiceException(ResponseCode.REPETITIVE_OPERATION.getMsg());

}

Long del = jedisUtil.del(token);

if (del <= 0) {

throw new ServiceException(ResponseCode.REPETITIVE_OPERATION.getMsg());

}

}

}TestApplication

@SpringBootApplication

@MapperScan("com.wangzaiplus.test.mapper")

public class TestApplication extends WebMvcConfigurerAdapter {

public static void main(String[] args) {

SpringApplication.run(TestApplication.class, args);

}

/**

* 跨域

* @return

*/

@Bean

public CorsFilter corsFilter() {

final UrlBasedCorsConfigurationSource urlBasedCorsConfigurationSource = new UrlBasedCorsConfigurationSource();

final CorsConfiguration corsConfiguration = new CorsConfiguration();

corsConfiguration.setAllowCredentials(true);

corsConfiguration.addAllowedOrigin("*");

corsConfiguration.addAllowedHeader("*");

corsConfiguration.addAllowedMethod("*");

urlBasedCorsConfigurationSource.registerCorsConfiguration("/**", corsConfiguration);

return new CorsFilter(urlBasedCorsConfigurationSource);

}

@Override

public void addInterceptors(InterceptorRegistry registry) {

// 接口幂等性拦截器

registry.addInterceptor(apiIdempotentInterceptor());

super.addInterceptors(registry);

}

@Bean

public ApiIdempotentInterceptor apiIdempotentInterceptor() {

return new ApiIdempotentInterceptor();

}

}OK, 目前为止, 校验代码准备就绪, 接下来测试验证

七、测试验证1、获取token的控制器TokenController

@RestController

@RequestMapping("/token")

public class TokenController {

@Autowired

private TokenService tokenService;

@GetMapping

public ServerResponse token() {

return tokenService.createToken();

}

}2、TestController, 注意@ApiIdempotent注解, 在需要幂等性校验的方法上声明此注解即可, 不需要校验的无影响

@RestController

@RequestMapping("/test")

@Slf4j

public class TestController {

@Autowired

private TestService testService;

@ApiIdempotent

@PostMapping("testIdempotence")

public ServerResponse testIdempotence() {

return testService.testIdempotence();

}

}3、获取token

查看redis

4、测试接口安全性: 利用jmeter测试工具模拟50个并发请求, 将上一步获取到的token作为参数

5、header或参数均不传token, 或者token值为空, 或者token值乱填, 均无法通过校验, 如token值为"abcd"

(整理：楚州电工考证培训学校)