<?xml version="1.0" encoding="utf-8" ?><rss version="2.0"><channel><title><![CDATA[BIGKEY的博客]]></title><description><![CDATA[]]></description><link>https://blog.youkuaiyun.com/BIGKEY</link><language>zh-cn</language><generator>https://blog.youkuaiyun.com/</generator><copyright><![CDATA[Copyright &copy; BIGKEY]]></copyright><item><title><![CDATA[Notepad++换行]]></title><link>https://blog.youkuaiyun.com/BIGKEY/article/details/121158469</link><guid>https://blog.youkuaiyun.com/BIGKEY/article/details/121158469</guid><author>BIGKEY</author><pubDate>Fri, 05 Nov 2021 10:48:41 +0800</pubDate><description><![CDATA[]]></description><category></category></item><item><title><![CDATA[IDEA快捷键]]></title><link>https://blog.youkuaiyun.com/BIGKEY/article/details/118519424</link><guid>https://blog.youkuaiyun.com/BIGKEY/article/details/118519424</guid><author>BIGKEY</author><pubDate>Tue, 06 Jul 2021 14:14:54 +0800</pubDate><description><![CDATA[实体类常用：alt+insert

]]></description><category></category></item><item><title><![CDATA[Linux常用命令]]></title><link>https://blog.youkuaiyun.com/BIGKEY/article/details/116264058</link><guid>https://blog.youkuaiyun.com/BIGKEY/article/details/116264058</guid><author>BIGKEY</author><pubDate>Thu, 29 Apr 2021 11:11:31 +0800</pubDate><description><![CDATA[查看实时日志
tail -f error.log
指定行数
tail -1000f error.log

]]></description><category></category></item><item><title><![CDATA[悲观锁和乐观锁]]></title><link>https://blog.youkuaiyun.com/BIGKEY/article/details/113194692</link><guid>https://blog.youkuaiyun.com/BIGKEY/article/details/113194692</guid><author>BIGKEY</author><pubDate>Tue, 26 Jan 2021 21:00:53 +0800</pubDate><description><![CDATA[锁机制的作用是保证共享资源可以进行排他性的访问；
悲观锁悲观的认为在数据处理过程中极有可能存在修改数据的并发事务（包括本系统的其他事务或来自外部系统的事务），于是将处理的数据设置为锁定状态。但是由于悲观锁排他性的数据访问会对系统性能造成严重影响。
乐观锁对并发事务持乐观态度（认为对数据的并发操作不会经常性的发生），通过更加宽松的锁机制来解决，最常见的乐观锁是通过数据版本标识来实现的。

...]]></description><category></category></item><item><title><![CDATA[Integer和int的区别]]></title><link>https://blog.youkuaiyun.com/BIGKEY/article/details/113192339</link><guid>https://blog.youkuaiyun.com/BIGKEY/article/details/113192339</guid><author>BIGKEY</author><pubDate>Tue, 26 Jan 2021 20:38:03 +0800</pubDate><description><![CDATA[区别：
1、integer是int的包装类，int是Java的一种基本数据结构 
2、integer变量必须实例化后才能使用，int变量不需要 
3、integer实际是对象的引用，int是直接存储数据值 
4、integer的默认值是null，int的默认值是0

比较：
首先要明白equals和==的区别：
Equals通常用来比较两个对象的内容是否相等，
==用来比较两个对象的地址是否相等；
Object类中的equals方法定义为判断两个对象的地址是否相等（可以理解成是否是同一个对象），此时就等同于]]></description><category></category></item><item><title><![CDATA[Map的遍历]]></title><link>https://blog.youkuaiyun.com/BIGKEY/article/details/111567825</link><guid>https://blog.youkuaiyun.com/BIGKEY/article/details/111567825</guid><author>BIGKEY</author><pubDate>Tue, 22 Dec 2020 21:45:34 +0800</pubDate><description><![CDATA[package com.test;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
// 遍历Map
public class ForMap {
public static void main(String[] args) {

    HashMap&lt;Integer, String&gt; map = new HashMap&lt;&gt;();
    map.put(1,"AAA");
    ]]></description><category></category></item><item><title><![CDATA[ArrayList和LinkedList的区别]]></title><link>https://blog.youkuaiyun.com/BIGKEY/article/details/111466411</link><guid>https://blog.youkuaiyun.com/BIGKEY/article/details/111466411</guid><author>BIGKEY</author><pubDate>Mon, 21 Dec 2020 07:01:00 +0800</pubDate><description><![CDATA[底层结构：
1、ArrayList底层是数组，查询快，增删慢；
2、LinkedList底层是链表，增删快，查询慢；
遍历速度：
1、ArrayList用for循环遍历速度更快
2、LinkedList用迭代器遍历速度更快


]]></description><category></category></item><item><title><![CDATA[SQL中where和having的区别]]></title><link>https://blog.youkuaiyun.com/BIGKEY/article/details/111415228</link><guid>https://blog.youkuaiyun.com/BIGKEY/article/details/111415228</guid><author>BIGKEY</author><pubDate>Sun, 20 Dec 2020 11:39:52 +0800</pubDate><description><![CDATA[SQL中where和having的区别
1、where可以用在增删改查多种语句中，而having只能用在查询语句中；
2、where是在分组之前执行，having是在分组之后执行；
3、where的子句having都可以跟，但是having有的子句where不能跟，比如集合函数；

...]]></description><category></category></item><item><title><![CDATA[关于数据结构]]></title><link>https://blog.youkuaiyun.com/BIGKEY/article/details/106801371</link><guid>https://blog.youkuaiyun.com/BIGKEY/article/details/106801371</guid><author>BIGKEY</author><pubDate>Wed, 17 Jun 2020 10:02:40 +0800</pubDate><description><![CDATA[栈：先进后出，如子弹进弹夹；
队列：先进先出，如火车过山洞；
数组：查询快，增删慢，如根据房间号找房间；
链表：增删快，查询慢，节点分数据域和指针域， 如链条一环扣一环；


]]></description><category></category></item><item><title><![CDATA[IDEA使用模板创建web项目失败时怎么解决？]]></title><link>https://blog.youkuaiyun.com/BIGKEY/article/details/106178261</link><guid>https://blog.youkuaiyun.com/BIGKEY/article/details/106178261</guid><author>BIGKEY</author><pubDate>Sun, 17 May 2020 18:06:01 +0800</pubDate><description><![CDATA[在本地仓库执行如下操作~


]]></description><category></category></item><item><title><![CDATA[NoSuchMethodError: org.apache.spark.internal.config.TypedConfigBuilder.checkValue]]></title><link>https://blog.youkuaiyun.com/BIGKEY/article/details/105711896</link><guid>https://blog.youkuaiyun.com/BIGKEY/article/details/105711896</guid><author>BIGKEY</author><pubDate>Thu, 23 Apr 2020 17:02:46 +0800</pubDate><description><![CDATA[版本不一致造成的!


]]></description><category></category></item><item><title><![CDATA[自定义程序输入输出路径]]></title><link>https://blog.youkuaiyun.com/BIGKEY/article/details/105664432</link><guid>https://blog.youkuaiyun.com/BIGKEY/article/details/105664432</guid><author>BIGKEY</author><pubDate>Tue, 21 Apr 2020 18:14:42 +0800</pubDate><description><![CDATA[]]></description><category></category></item><item><title><![CDATA[Maven倒入依赖失败解决方案]]></title><link>https://blog.youkuaiyun.com/BIGKEY/article/details/105133689</link><guid>https://blog.youkuaiyun.com/BIGKEY/article/details/105133689</guid><author>BIGKEY</author><pubDate>Fri, 27 Mar 2020 09:05:19 +0800</pubDate><description><![CDATA[依赖下载失败，相关文件夹中多了以 .lastUpdated为后缀的文件，此时，如果开发者在开发工具中反复导入，会发现始终无法导入成功，这个时候就需要删除本地仓库中相关的 .lastUpdated文件，可以通过文件搜索找到本地仓库中所有的以 .lastUpdated为后缀的文件，再在开发工具中重新Reimport maven导入依赖。
如果对应的jar包依赖依然不存在，说明拉取失败，删除相应的依赖文...]]></description><category></category></item><item><title><![CDATA[Error: Please select a valid Python interpreter（运行报错）]]></title><link>https://blog.youkuaiyun.com/BIGKEY/article/details/104997736</link><guid>https://blog.youkuaiyun.com/BIGKEY/article/details/104997736</guid><author>BIGKEY</author><pubDate>Fri, 20 Mar 2020 20:19:05 +0800</pubDate><description><![CDATA[选择设置（Ctrl+Alt+S）并搜索Interpreter


]]></description><category></category></item><item><title><![CDATA[虚拟机JDK配置]]></title><link>https://blog.youkuaiyun.com/BIGKEY/article/details/104493296</link><guid>https://blog.youkuaiyun.com/BIGKEY/article/details/104493296</guid><author>BIGKEY</author><pubDate>Tue, 25 Feb 2020 11:35:03 +0800</pubDate><description><![CDATA[查询
[root@hadoop101 ~]# rpm -qa | grep jdk

卸载
[root@hadoop101 ~]# yum -y remove java-1.7.0-openjdk-1.7.0.99-2.6.5.1.el6.x86_64

安装
解压
[root@hadoop101 software]# tar -zxvf jdk-8u144-linux-x64.tar.gz -C...]]></description><category></category></item><item><title><![CDATA[在windows环境上配置HADOOP_HOME环境变量]]></title><link>https://blog.youkuaiyun.com/BIGKEY/article/details/104401956</link><guid>https://blog.youkuaiyun.com/BIGKEY/article/details/104401956</guid><author>BIGKEY</author><pubDate>Wed, 19 Feb 2020 22:18:29 +0800</pubDate><description><![CDATA[修改D:\hadoop-2.7.2\etc\hadoop\hadoop-env.cmd文件

在D:\hadoop-2.7.2\bin目录下添加winutils.exe文件

]]></description><category></category></item><item><title><![CDATA[强制删除HDFS非空文件夹]]></title><link>https://blog.youkuaiyun.com/BIGKEY/article/details/104396521</link><guid>https://blog.youkuaiyun.com/BIGKEY/article/details/104396521</guid><author>BIGKEY</author><pubDate>Wed, 19 Feb 2020 17:12:53 +0800</pubDate><description><![CDATA[hadoop fs -rm -r -skipTrash /文件夹名

]]></description><category></category></item><item><title><![CDATA[配置虚拟机网络]]></title><link>https://blog.youkuaiyun.com/BIGKEY/article/details/104394914</link><guid>https://blog.youkuaiyun.com/BIGKEY/article/details/104394914</guid><author>BIGKEY</author><pubDate>Wed, 19 Feb 2020 16:06:37 +0800</pubDate><description><![CDATA[修改IP地址
[root@centos003 桌面]# vi /etc/sysconfig/network-scripts/ifcfg-eth0 

重启网络服务
[root@centos003 桌面]# service network restsart


]]></description><category></category></item><item><title><![CDATA[虚拟机主机映射文件]]></title><link>https://blog.youkuaiyun.com/BIGKEY/article/details/104378580</link><guid>https://blog.youkuaiyun.com/BIGKEY/article/details/104378580</guid><author>BIGKEY</author><pubDate>Tue, 18 Feb 2020 17:15:50 +0800</pubDate><description><![CDATA[修改个主机名：
[root@hadoop101 桌面]# vi /etc/sysconfig/network

配置主机名和IP映射关系
[root@hadoop101 桌面]# vi /etc/hosts

Window系统的主机映射文件
‪C:\Windows\System32\drivers\etc\hosts


...]]></description><category></category></item><item><title><![CDATA[eclipse快捷键]]></title><link>https://blog.youkuaiyun.com/BIGKEY/article/details/104336244</link><guid>https://blog.youkuaiyun.com/BIGKEY/article/details/104336244</guid><author>BIGKEY</author><pubDate>Sat, 15 Feb 2020 22:43:27 +0800</pubDate><description><![CDATA[生成set和get方法：Alt+Shift+S
注释：Ctrl+/
提示：Alt+/

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