<?xml version="1.0" encoding="utf-8" ?><rss version="2.0"><channel><title><![CDATA[玉儿小跟班]]></title><description><![CDATA[致力于成为一名有用的程序猿]]></description><link>https://blog.youkuaiyun.com/Little127</link><language>zh-cn</language><generator>https://blog.youkuaiyun.com/</generator><copyright><![CDATA[Copyright &copy; Little127]]></copyright><item><title><![CDATA[Java连接HBASE数据库]]></title><link>https://blog.youkuaiyun.com/Little127/article/details/118576111</link><guid>https://blog.youkuaiyun.com/Little127/article/details/118576111</guid><author>Little127</author><pubDate>Thu, 08 Jul 2021 16:29:06 +0800</pubDate><description><![CDATA[HBASE是建立在Hadoop分布式系统基础之上的列模式数据库，Java连接HBASE需要如下几个jar包：hadoop-common、hadoop-mapreduce-client-core、hbase-common、hbase-client。这些jar包在maven仓库里都有，地址：https://mvnrepository.com/artifact/org.apache.hadoop，打开pom.xml文件拷贝如下代码进行自动导包（包版本自己选）


&lt;!-- https://mvnreposi]]></description><category></category></item><item><title><![CDATA[HBASE报错汇总及故障解决]]></title><link>https://blog.youkuaiyun.com/Little127/article/details/118574518</link><guid>https://blog.youkuaiyun.com/Little127/article/details/118574518</guid><author>Little127</author><pubDate>Thu, 08 Jul 2021 15:59:43 +0800</pubDate><description><![CDATA[查询HBASE日志：

cd/home/hadoop/software/hbase-1.3.1/logs

tail -100f hbase-root-master-主机名.log



报错1： util.FSUtils: Waiting for dfs to exit safe mode...

解答：这个是HBASE没有关闭安全模式导致的，bin/hbase shell能够正常连接数据库，但使用hbase命令如list会报如上错误。

解决：

su hadoop
cd /home/hadoop/..]]></description><category></category></item><item><title><![CDATA[Java连接阿里云大数据计算服务Maxcompute（ODPS）]]></title><link>https://blog.youkuaiyun.com/Little127/article/details/118572364</link><guid>https://blog.youkuaiyun.com/Little127/article/details/118572364</guid><author>Little127</author><pubDate>Thu, 08 Jul 2021 14:22:56 +0800</pubDate><description><![CDATA[连接阿里大数据服务Maxcompute（以前叫ODPS）需要阿里云账号，IntelliJ IDEA配置Maxcompute步骤查看阿里官方文档：https://help.aliyun.com/document_detail/50892.html?spm=a2c4g.11186623.6.1045.6d575d9c7XfQWe，连接Maxcompute代码如下：


import com.aliyun.odps.Odps;
import com.aliyun.odps.PartitionSpec;
impo.]]></description><category></category></item><item><title><![CDATA[SQL循环查询父节点信息]]></title><link>https://blog.youkuaiyun.com/Little127/article/details/118569758</link><guid>https://blog.youkuaiyun.com/Little127/article/details/118569758</guid><author>Little127</author><pubDate>Thu, 08 Jul 2021 13:29:32 +0800</pubDate><description><![CDATA[解决问题：日常关系表中只会存放一层父子关系信息，要求循环追溯查询出所有层级的父节点。

子--&gt;父1--&gt;父2--&gt;父3--&gt;...，示例使用的Postgre数据库，其他数据库同样适用。

一般思路采用不断left join向上搜寻，代码如下：


​create table test(id int,name varchar(100),parentId int);  --初始化父子关系表
insert into test values(101,'a',100);
insert int]]></description><category></category></item><item><title><![CDATA[MapReduce传入参数]]></title><link>https://blog.youkuaiyun.com/Little127/article/details/118567858</link><guid>https://blog.youkuaiyun.com/Little127/article/details/118567858</guid><author>Little127</author><pubDate>Thu, 08 Jul 2021 10:32:56 +0800</pubDate><description><![CDATA[在main()中进行参数传入，Jobconf直接进行set即可，示例传入字符串类型setString()


public static void main(String[] args) throws Exception{
    JobConf conf = new JobConf();
    conf.setString("pt","20210708");
}

在Map或Reduce获取传入的参数，context可以获取当前作业的很多信息，直接getJobconf即可


@Override
pub]]></description><category></category></item></channel></rss>