<?xml version="1.0" encoding="utf-8" ?><rss version="2.0"><channel><title><![CDATA[整理输出各类知识]]></title><description><![CDATA[]]></description><link>https://blog.youkuaiyun.com/Qy1997</link><language>zh-cn</language><generator>https://blog.youkuaiyun.com/</generator><copyright><![CDATA[Copyright &copy; Qy1997]]></copyright><item><title><![CDATA[工作思考|研发环境好好的，怎么上线就出问题了？]]></title><link>https://blog.youkuaiyun.com/Qy1997/article/details/136997058</link><guid>https://blog.youkuaiyun.com/Qy1997/article/details/136997058</guid><author>Qy1997</author><pubDate>Sun, 24 Mar 2024 22:14:46 +0800</pubDate><description><![CDATA[此次线上问题复习了Bean的生命周期，复习了两个接口，复习了@DependsOn注解。]]></description><category></category></item><item><title><![CDATA[动手学习|如何创建自己的starter？]]></title><link>https://blog.youkuaiyun.com/Qy1997/article/details/136972627</link><guid>https://blog.youkuaiyun.com/Qy1997/article/details/136972627</guid><author>Qy1997</author><pubDate>Sat, 23 Mar 2024 18:42:59 +0800</pubDate><description><![CDATA[不错不错，自动配置简单原理明白了，也能写个starter了，说不定以后能写些东西让别人依赖一下（哈哈哈，开始做梦）。]]></description><category></category></item><item><title><![CDATA[【PgSQL】聚合函数string_agg]]></title><link>https://blog.youkuaiyun.com/Qy1997/article/details/135442930</link><guid>https://blog.youkuaiyun.com/Qy1997/article/details/135442930</guid><author>Qy1997</author><pubDate>Sun, 07 Jan 2024 18:39:32 +0800</pubDate><description><![CDATA[在工作中，遇到了这样的需求，需要根据某一个字段A分组查询，统计数量，同时还要查询另一个字段B，但是呢这个字段B在分组后的记录中存在不同的值。后来，经老同事的提醒，得知了string_agg这个函数，便稍微查询整理了一下。由于工作中使用的是pgsql，所以以上是pgSQL中string_agg函数的用法，很多情况下还是会用到mysql的，所以我查了一下mysql是否也有相关的函数，mysql果然没有让我失望，类似的函数叫做group_concat。张三 |足球-羽毛球-足球|王五 |乒乓球-乒乓球|]]></description><category></category></item><item><title><![CDATA[【数据库-BUG】limit和order by一起使用出现的分页重复数据Bug]]></title><link>https://blog.youkuaiyun.com/Qy1997/article/details/129720318</link><guid>https://blog.youkuaiyun.com/Qy1997/article/details/129720318</guid><author>Qy1997</author><pubDate>Wed, 22 Mar 2023 21:54:06 +0800</pubDate><description><![CDATA[在使用limit和order by进行分页时，发现有的数据会在两个页面重复出现。]]></description><category></category></item><item><title><![CDATA[【PostgreSQL】查询语句排序]]></title><link>https://blog.youkuaiyun.com/Qy1997/article/details/129337922</link><guid>https://blog.youkuaiyun.com/Qy1997/article/details/129337922</guid><author>Qy1997</author><pubDate>Sat, 04 Mar 2023 19:08:04 +0800</pubDate><description><![CDATA[时，数据库本身有自己对null的大小处理逻辑，有时候数据库的处理并不符合业务逻辑，此时，我们可以使用如下方法指定空值的顺序。在使用SQL语句进行数据查询时，我们经常会对查询结果进行排序，比如这样，指定返回的数据根据字段进行升序或者降序，但是，在数据为。指定空值在最前面还是最后面。]]></description><category></category></item><item><title><![CDATA[【Spring】接口之InitializingBean]]></title><link>https://blog.youkuaiyun.com/Qy1997/article/details/129148286</link><guid>https://blog.youkuaiyun.com/Qy1997/article/details/129148286</guid><author>Qy1997</author><pubDate>Tue, 21 Feb 2023 19:29:16 +0800</pubDate><description><![CDATA[InitializingBean接口为bean提供了初始化方法的方式，它只包括afterPropertiesSet方法，凡是继承该接口的类，在初始化bean的时候都会执行该方法。但这不是本文要讲的内容，本文要讲的是这个接口的一个应用。]]></description><category></category></item><item><title><![CDATA[【Mybatis】if标签中判断字符串相等]]></title><link>https://blog.youkuaiyun.com/Qy1997/article/details/129135732</link><guid>https://blog.youkuaiyun.com/Qy1997/article/details/129135732</guid><author>Qy1997</author><pubDate>Tue, 21 Feb 2023 09:03:14 +0800</pubDate><description><![CDATA[在使用Mybatis的过程中需要使用if标签进行字符串的判断从而拼接不同的sql。发现这个字符串判等并不生效。]]></description><category></category></item><item><title><![CDATA[【常用工具类】EasyExcel]]></title><link>https://blog.youkuaiyun.com/Qy1997/article/details/128364368</link><guid>https://blog.youkuaiyun.com/Qy1997/article/details/128364368</guid><author>Qy1997</author><pubDate>Sun, 18 Dec 2022 18:04:00 +0800</pubDate><description><![CDATA[项目中经常会用到表格的读写，导入（上传）、导出（下载）比较常用的就是EasyExcel。]]></description><category></category></item><item><title><![CDATA[【Mybatis】xml文件中的特殊字符转义]]></title><link>https://blog.youkuaiyun.com/Qy1997/article/details/128222202</link><guid>https://blog.youkuaiyun.com/Qy1997/article/details/128222202</guid><author>Qy1997</author><pubDate>Wed, 07 Dec 2022 16:17:25 +0800</pubDate><description><![CDATA[mybatis xml文件中的特殊字符转义]]></description><category></category></item><item><title><![CDATA[【JDK】Stream在各场景下的使用]]></title><link>https://blog.youkuaiyun.com/Qy1997/article/details/127795286</link><guid>https://blog.youkuaiyun.com/Qy1997/article/details/127795286</guid><author>Qy1997</author><pubDate>Thu, 10 Nov 2022 20:18:45 +0800</pubDate><description><![CDATA[Stream在各场景下的使用]]></description><category></category></item><item><title><![CDATA[【JDK】Comparable与Comparator通俗易懂版]]></title><link>https://blog.youkuaiyun.com/Qy1997/article/details/127785657</link><guid>https://blog.youkuaiyun.com/Qy1997/article/details/127785657</guid><author>Qy1997</author><pubDate>Thu, 10 Nov 2022 15:27:50 +0800</pubDate><description><![CDATA[Comparable与Comparator]]></description><category></category></item><item><title><![CDATA[【常用工具类】fastjson]]></title><link>https://blog.youkuaiyun.com/Qy1997/article/details/127641374</link><guid>https://blog.youkuaiyun.com/Qy1997/article/details/127641374</guid><author>Qy1997</author><pubDate>Tue, 01 Nov 2022 21:10:10 +0800</pubDate><description><![CDATA[在项目种经常要调用第三方的接口获取返回值，返回结果一般都是JSON格式的字符串，需要使用JSON解析工具进行解析，比较常用的就是fastjson。将对象或者集合序列化成JSON字符串。将JSON字符串反序列化为指定对象。将JSON数组的字符串转换为集合。目前感觉这三个在项目中就够用了。]]></description><category></category></item><item><title><![CDATA[【SpringBoot】常用的的各种注解（二）：Controller层相关注解]]></title><link>https://blog.youkuaiyun.com/Qy1997/article/details/127603329</link><guid>https://blog.youkuaiyun.com/Qy1997/article/details/127603329</guid><author>Qy1997</author><pubDate>Sun, 30 Oct 2022 20:17:37 +0800</pubDate><description><![CDATA[Controller层注解]]></description><category></category></item><item><title><![CDATA[【Kafka-BUG】Kafka消息无法正常消费]]></title><link>https://blog.youkuaiyun.com/Qy1997/article/details/127554960</link><guid>https://blog.youkuaiyun.com/Qy1997/article/details/127554960</guid><author>Qy1997</author><pubDate>Thu, 27 Oct 2022 16:15:08 +0800</pubDate><description><![CDATA[Kafka消息无法正常消费]]></description><category></category></item><item><title><![CDATA[【SpringBoot】restTemplate接口请求设置超时时间]]></title><link>https://blog.youkuaiyun.com/Qy1997/article/details/127539528</link><guid>https://blog.youkuaiyun.com/Qy1997/article/details/127539528</guid><author>Qy1997</author><pubDate>Wed, 26 Oct 2022 20:04:08 +0800</pubDate><description><![CDATA[restTemplate接口请求设置超时时间]]></description><category></category></item><item><title><![CDATA[【SpringBoot】常用的的各种注解（一）:Controller中的请求参数]]></title><link>https://blog.youkuaiyun.com/Qy1997/article/details/127466218</link><guid>https://blog.youkuaiyun.com/Qy1997/article/details/127466218</guid><author>Qy1997</author><pubDate>Sat, 22 Oct 2022 20:09:46 +0800</pubDate><description><![CDATA[SpringBoot常用的的各种注解（一）:Controller中的请求参数
Controller中的请求参数相关注解
@PathVariable
@RequestParam
@RequestBody
@RequestHeader
@CookieValue]]></description><category></category></item><item><title><![CDATA[【SpringBoot-BUG】yml配置文件中的关键字on冲突]]></title><link>https://blog.youkuaiyun.com/Qy1997/article/details/127425689</link><guid>https://blog.youkuaiyun.com/Qy1997/article/details/127425689</guid><author>Qy1997</author><pubDate>Thu, 20 Oct 2022 14:09:39 +0800</pubDate><description><![CDATA[当nacos中的yml配置文件没有这个配置的时候，代码读取注解上的默认值，运行正常当nacos中的yml配置文件增加了这个配置时，代码运行异常，打断点后发现，param这个值注入的属性值为String类型的true，百思不得其解这个true是从哪来的。]]></description><category></category></item><item><title><![CDATA[【PostgreSQL】WITH RECURSIVE递归查询语句]]></title><link>https://blog.youkuaiyun.com/Qy1997/article/details/127213147</link><guid>https://blog.youkuaiyun.com/Qy1997/article/details/127213147</guid><author>Qy1997</author><pubDate>Sat, 08 Oct 2022 17:52:01 +0800</pubDate><description><![CDATA[PostgreSQL提供了WITH语句，允许你构造用于查询的辅助语句。这些语句通常称为公共表表达式(Common Table Expressions)cte。]]></description><category></category></item><item><title><![CDATA[【PostgreSQL】ON CONFLICT语句]]></title><link>https://blog.youkuaiyun.com/Qy1997/article/details/127211669</link><guid>https://blog.youkuaiyun.com/Qy1997/article/details/127211669</guid><author>Qy1997</author><pubDate>Sat, 08 Oct 2022 16:49:14 +0800</pubDate><description><![CDATA[PgSQL中的insert语句可以通过来判断是否有唯一键冲突然后选择放弃插入操作，或者进行更新操作。]]></description><category></category></item><item><title><![CDATA[【数据库BUG】Caused by: java.io.IOException: Tried to send an out-of-range integer as a 2-byte value]]></title><link>https://blog.youkuaiyun.com/Qy1997/article/details/126974274</link><guid>https://blog.youkuaiyun.com/Qy1997/article/details/126974274</guid><author>Qy1997</author><pubDate>Wed, 21 Sep 2022 15:47:45 +0800</pubDate><description><![CDATA[数据库bug]]></description><category></category></item></channel></rss>