1.添加有参构造,忘记添加无参构造
## 错误提示
(no Creators, like default construct, exist ): cannot deserialize from Object value (no delegate- or property-based Creator)
2.忘记注入@Autowired
## 错误提示
``` Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is java.lang.NullPointerException] with root cause
java.lang.NullPointerException: null
3.Map的key是Long类型,获取时,传入string
4.v-if后边的值不需要加{}
<li v-if="search.page<4" :class="{active: search.page==i}" v-for="i in 5">
<a href="#">{{i}}</a>
</li>
5.因为买了阿里云以及新配了一个电脑，把项目的数据库，fastDFS，elasticsearch等从虚拟机迁移到阿里云上遇到的大坑
Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed;
nested exception is feign.RetryableException:
Read timed out executing GET http://item-service/spu/page?saleable=true&page=1&rows=100] with root cause
java.net.SocketTimeoutException: Read timed out
用程序把数据库的内容导入elasticsearch时，出现错误，搞到凌晨两点钟才大概有一点点接近真相。
- 出错的一部分原因是当时写导入程序应该用测试类直接运行，但是当时测试类一直报错。就另辟蹊径直接写个controller用get请求直接调用。
-由于当时虚拟机处于一个局域网络 网速快，程序能很快处理完成。所有没有出错。而阿里云既要查询数据库，还要存入elasticsearch并不能很快完成。由于ribbon、hystrix的设置超时时间不大于程序执行时间，所以导致报错。
ribbon:
ConnectTimeout: 1000 # 连接超时时间(ms)1000
ReadTimeout: 3500 # 通信超时时间(ms)3500
MaxAutoRetriesNextServer: 0 # 同一服务不同实例的重试次数
MaxAutoRetries: 0 # 同一实例的重试次数
hystrix:
command:
default:
execution:
isolation:
thread:
timeoutInMillisecond: 5000 # 熔断超时时长：10000ms5000
6 因为要聚合spec里的子字段，没有按照正确格式写
图片.png
错误提示，因为聚合时字段填写错误 结果为为空，后续代码调用报错
org.elasticsearch.search.aggregations.bucket.terms.UnmappedTerms cannot be cast to org.elasticsearch.search.aggregations.bucket.terms.StringTerms
queryBuilder1.addAggregation(AggregationBuilders.terms(specParam.getName()).field("specs." + specParam.getName() + ".keyword"));//正确代码
queryBuilder1.addAggregation(AggregationBuilders.terms(specParam.getName()).field(specParam.getName()));//错误代码
7 使用feign调用接口 路径没写全
Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed;
nested exception is feign.FeignException:
status 404 reading SpecificationClient#queryGroupAndParamByCid(Long); content:{"timestamp":"2020-06-09T13:48:28.857+0000",
"status":404,
"error":"Not Found",
"message":"No message available",
"path":"/groupsAndParam/76"}] with root cause
