<?xml version="1.0" encoding="utf-8" ?><rss version="2.0"><channel><title><![CDATA[chenkaibsw的专栏]]></title><description><![CDATA[]]></description><link>https://blog.youkuaiyun.com/chenkaibsw</link><language>zh-cn</language><generator>https://blog.youkuaiyun.com/</generator><copyright><![CDATA[Copyright &copy; chenkaibsw]]></copyright><item><title><![CDATA[1.数据库相关知识点整理]]></title><link>https://blog.youkuaiyun.com/chenkaibsw/article/details/109522582</link><guid>https://blog.youkuaiyun.com/chenkaibsw/article/details/109522582</guid><author>chenkaibsw</author><pubDate>Wed, 28 Jun 2023 22:57:22 +0800</pubDate><description><![CDATA[数据库相关：

mysql执行计划

记录：

ref:返回匹配的某个单独值值的所有行

range:检索指定范围的行

index：遍历了索引树

敖丙——数据库索引整理

敖丙——数据库调优

分库分表

mysql语句加锁分析

mysql锁

sql注入

sql防注入

数据库锁

数据库优化规范

mysql日志

MySql保证数据不丢失：

https://mp.weixin.qq.com/s?__biz=MzA5MTkxMDQ4MQ==&amp;mid=2648933461&amp;idx]]></description><category></category></item><item><title><![CDATA[Linux无法账号密码登录问题]]></title><link>https://blog.youkuaiyun.com/chenkaibsw/article/details/127548422</link><guid>https://blog.youkuaiyun.com/chenkaibsw/article/details/127548422</guid><author>chenkaibsw</author><pubDate>Thu, 27 Oct 2022 11:19:21 +0800</pubDate><description><![CDATA[账号密码登录]]></description><category></category></item><item><title><![CDATA[linux下生成ssh密钥并获取密钥]]></title><link>https://blog.youkuaiyun.com/chenkaibsw/article/details/104188294</link><guid>https://blog.youkuaiyun.com/chenkaibsw/article/details/104188294</guid><author>chenkaibsw</author><pubDate>Tue, 25 Oct 2022 19:06:55 +0800</pubDate><description><![CDATA[生成密钥

ssh-keygen -t rsa -f ~/.ssh/id_rsa -N '密码'

 -t指定密钥产生算法
 -f指定生成文件，登陆是使用ssh命令进行的，而他的配置文件默认的私钥为家目录下.ssh/id_rsa
 -N对私钥加密以防止私钥泄露后他人乱用，但这也使得以后每次登陆必须输入-N指定的密码。

https://blog.youkuaiyun.com/nahancy/articl...]]></description><category></category></item><item><title><![CDATA[Redis学习笔记—常见应用场景—BitMap]]></title><link>https://blog.youkuaiyun.com/chenkaibsw/article/details/126075045</link><guid>https://blog.youkuaiyun.com/chenkaibsw/article/details/126075045</guid><author>chenkaibsw</author><pubDate>Mon, 15 Aug 2022 11:42:17 +0800</pubDate><description><![CDATA[redis bitmap使用]]></description><category></category></item><item><title><![CDATA[在Java中使用CRC32]]></title><link>https://blog.youkuaiyun.com/chenkaibsw/article/details/126256613</link><guid>https://blog.youkuaiyun.com/chenkaibsw/article/details/126256613</guid><author>chenkaibsw</author><pubDate>Tue, 09 Aug 2022 22:04:28 +0800</pubDate><description><![CDATA[CRC32]]></description><category></category></item><item><title><![CDATA[浏览器下载文件]]></title><link>https://blog.youkuaiyun.com/chenkaibsw/article/details/126136020</link><guid>https://blog.youkuaiyun.com/chenkaibsw/article/details/126136020</guid><author>chenkaibsw</author><pubDate>Wed, 03 Aug 2022 10:45:44 +0800</pubDate><description><![CDATA[下载文件]]></description><category></category></item><item><title><![CDATA[读取文件内容并解析]]></title><link>https://blog.youkuaiyun.com/chenkaibsw/article/details/125753120</link><guid>https://blog.youkuaiyun.com/chenkaibsw/article/details/125753120</guid><author>chenkaibsw</author><pubDate>Tue, 12 Jul 2022 22:08:08 +0800</pubDate><description><![CDATA[读取文件并解析]]></description><category></category></item><item><title><![CDATA[CacheManager配置]]></title><link>https://blog.youkuaiyun.com/chenkaibsw/article/details/125671519</link><guid>https://blog.youkuaiyun.com/chenkaibsw/article/details/125671519</guid><author>chenkaibsw</author><pubDate>Fri, 08 Jul 2022 09:24:03 +0800</pubDate><description><![CDATA[CacheManager配置]]></description><category></category></item><item><title><![CDATA[@ConfigurationProperties修饰的类中是静态属性]]></title><link>https://blog.youkuaiyun.com/chenkaibsw/article/details/125671137</link><guid>https://blog.youkuaiyun.com/chenkaibsw/article/details/125671137</guid><author>chenkaibsw</author><pubDate>Fri, 08 Jul 2022 09:09:04 +0800</pubDate><description><![CDATA[@ConfigurationProperties]]></description><category></category></item><item><title><![CDATA[Sharding-JDBC实现读写分离]]></title><link>https://blog.youkuaiyun.com/chenkaibsw/article/details/125643322</link><guid>https://blog.youkuaiyun.com/chenkaibsw/article/details/125643322</guid><author>chenkaibsw</author><pubDate>Wed, 06 Jul 2022 16:58:45 +0800</pubDate><description><![CDATA[数据库读写分离]]></description><category></category></item><item><title><![CDATA[mybatis中使用Java8的日期LocalDate、LocalDateTime]]></title><link>https://blog.youkuaiyun.com/chenkaibsw/article/details/125515541</link><guid>https://blog.youkuaiyun.com/chenkaibsw/article/details/125515541</guid><author>chenkaibsw</author><pubDate>Wed, 29 Jun 2022 10:42:48 +0800</pubDate><description><![CDATA[LocalDate LocalDateTime的使用]]></description><category></category></item><item><title><![CDATA[【无标题】剑指offer——寻找峰值]]></title><link>https://blog.youkuaiyun.com/chenkaibsw/article/details/125458725</link><guid>https://blog.youkuaiyun.com/chenkaibsw/article/details/125458725</guid><author>chenkaibsw</author><pubDate>Sat, 25 Jun 2022 14:25:47 +0800</pubDate><description><![CDATA[无]]></description><category></category></item><item><title><![CDATA[IDEA Database 查询中文乱码的解决方法]]></title><link>https://blog.youkuaiyun.com/chenkaibsw/article/details/125415392</link><guid>https://blog.youkuaiyun.com/chenkaibsw/article/details/125415392</guid><author>chenkaibsw</author><pubDate>Wed, 22 Jun 2022 19:27:19 +0800</pubDate><description><![CDATA[IDEA使用]]></description><category></category></item><item><title><![CDATA[gateway 限流]]></title><link>https://blog.youkuaiyun.com/chenkaibsw/article/details/125137285</link><guid>https://blog.youkuaiyun.com/chenkaibsw/article/details/125137285</guid><author>chenkaibsw</author><pubDate>Sun, 05 Jun 2022 21:44:02 +0800</pubDate><description><![CDATA[gateway 限流]]></description><category></category></item><item><title><![CDATA[消息队列—Kafka的顺序消费]]></title><link>https://blog.youkuaiyun.com/chenkaibsw/article/details/124917598</link><guid>https://blog.youkuaiyun.com/chenkaibsw/article/details/124917598</guid><author>chenkaibsw</author><pubDate>Sun, 22 May 2022 23:04:38 +0800</pubDate><description><![CDATA[背景:

下单生成一条消息，付款生成一条消息，下单消息和付款消息都封装为同样的JSON格式，订阅Kafka同一个topic，现在要求下单和付款有顺序性。

解决方案：

发送消息的时候下单消息和付款消息指定同样的partitionKey，此时Kafka经过hash运算，同一笔订单的下单消息和付款消息都在会落在同一个Partition中。此时可以满足先执行下单再执行付款。

如果消费者开启了线程池利用多线程处理，此时又可能出现先付款再消费的情况，此时可以利用Map缓存来解决问题。

获取消息，如果是下单消息，]]></description><category></category></item><item><title><![CDATA[解决 swap file swp already exists问题]]></title><link>https://blog.youkuaiyun.com/chenkaibsw/article/details/124900536</link><guid>https://blog.youkuaiyun.com/chenkaibsw/article/details/124900536</guid><author>chenkaibsw</author><pubDate>Sat, 21 May 2022 17:06:00 +0800</pubDate><description><![CDATA[在 Linux 下的vim编辑过程中，由于某种原因异常退出正在编辑的文件，再次编辑该文件时，会出现如下提示：



使用vim编辑文件实际是先 copy 一份临时文件并映射到内存给你编辑， 编辑的是临时文件， 当执行：w 后才保存临时文件到原文件，执行：q 后才删除临时文件。

每次启动检索是否有临时文件， 有则询问如何处理，就会出现如上情景。

解决办法：



将隐藏的 *.swp 文件删除即可，原先的文件便可再次编辑。




...]]></description><category></category></item><item><title><![CDATA[关与 @EnableConfigurationProperties 注解]]></title><link>https://blog.youkuaiyun.com/chenkaibsw/article/details/108674286</link><guid>https://blog.youkuaiyun.com/chenkaibsw/article/details/108674286</guid><author>chenkaibsw</author><pubDate>Wed, 18 May 2022 15:46:51 +0800</pubDate><description><![CDATA[@Configuration注解







下面对比上面的区别：下面的对象创建完放在Bean中，上面的只是创建了一个对象。此时可以使用@Bean注解。





特殊说明：


]]></description><category></category></item><item><title><![CDATA[Java如何理解多态]]></title><link>https://blog.youkuaiyun.com/chenkaibsw/article/details/124518718</link><guid>https://blog.youkuaiyun.com/chenkaibsw/article/details/124518718</guid><author>chenkaibsw</author><pubDate>Sat, 30 Apr 2022 21:08:01 +0800</pubDate><description><![CDATA[多态到底是啥，就是当子类继承父类的方法时，对其继承下来的方法按照自己的方式重新定义（覆盖重写），我用父类引用指向子类对象，可以实现每个该引用体现出不同继承同一个父类的子类表达自己的方法内容。提到多态肯定很多人会想到向上转型和向下转型，那今天就聊聊什么是向上转型和向下转型。

1.向上转型

之前继承有提到过。父类引用指向子类对象。这时的引用只能调用子类覆盖重写了的方法，不能调用子类特有方法。自动转换


public class Main {
 public static void main(Str...]]></description><category></category></item><item><title><![CDATA[No qualifying bean of type ‘javax.servlet.Filter‘ available]]></title><link>https://blog.youkuaiyun.com/chenkaibsw/article/details/124470228</link><guid>https://blog.youkuaiyun.com/chenkaibsw/article/details/124470228</guid><author>chenkaibsw</author><pubDate>Thu, 28 Apr 2022 11:37:04 +0800</pubDate><description><![CDATA[org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'javax.servlet.Filter' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {@org.springframework.beans.factory.annot.]]></description><category></category></item><item><title><![CDATA[数据库—索引失效原因解释]]></title><link>https://blog.youkuaiyun.com/chenkaibsw/article/details/124321169</link><guid>https://blog.youkuaiyun.com/chenkaibsw/article/details/124321169</guid><author>chenkaibsw</author><pubDate>Thu, 21 Apr 2022 21:33:25 +0800</pubDate><description><![CDATA[联合索引的失效问题分析：





范围查找的右边索引会失效。



如果a不是范围查询，此时a,b的索引都能使用到






//以a结尾的在B+树结构中并不是有序的
select * from test_user where a like '%a';
//以a开头的在B+树结构中是有序的
select * from test_user where a like 'a%';



示例：



第一条语句：





第二条语句：





第三条语句：








......]]></description><category></category></item></channel></rss>