在Liunx上安装Hive以及如何与Hadoop集成和将Hive的元数据存储到MySQL里,今天散仙就来看下,如何在Eclipse里通过JDBC的方式操作Hive.
我们都知道Hive是一个类SQL的框架,支持HSQL语法操作Hive,而Hive内部,会转成一个个MapReduce作业来完成具体的数据统计,虽然我们可以直接在Hive的shell里,向Hive发起命令,但这样做受限制比较多,如果我们能把它的操作结合在编程里,这样以来我们的Hive就会变得非常灵活了。
Hive是支持JDBC操作的,所以我们就可以像操作MySQL一样,在JAVA代码里,操作Hive,进行数据统计。
下面详细看下,操作步骤:
软件环境
序号 | 说明 | 系统 | 1 | centos6.5安装hadoop2.2.0 | linux | 2 | centos6.5安装Hive0.13 | linux | 3 | Eclipse4.2 | Windows7 |
序号 | 步骤 | 说明 | 1 | hadoop2.2.0安装,启动 | Hive依赖Hadoop环境 | 2 | hive安装 | 类SQL方式操作MapReduce | 3 | 启动hiveserver2 | 远程操作Hive的服务端程序 | 4 | 在win上新建一个java项目,并导入Hive所需jar包 | 远程操作必需步骤 | 5 | 在eclipse里编码,测试 | 测试连接hive是否成功 | 6 | 在hiveserver2端查看 | 检查是否对接成功和任务打印日志 | 7 | 在hadoop的8088端口上查看MR执行任务 | 查看MR执行调度 |
一些HIVE操作语句:
导入数据到一个表中:
LOAD DATA LOCAL INPATH '/home/search/abc1.txt' OVERWRITE INTO TABLE info;
show tables;//显示当前的所有的表
desc talbeName;查看当前表的字段结构
show databases;//查看所有的已有的数据库
建表语句
create table mytt (name string ,count int) row format delimited fields terminated by '#' stored as textfile ;
jar包,截图
Hive依赖Hadoop,因此客户端最好把hadoop的jar包夜引入项目中,下面是调用源码,运行前,确定你在服务端的hiversver2已经开启。
- package com.test;
- import java.sql.Connection;
- import java.sql.DriverManager;
- import java.sql.ResultSet;
- import java.sql.Statement;
- import org.apache.hadoop.conf.Configuration;
- /**
- * 在Win7上,使用JDBC操作Hive
- * @author qindongliang
- *
- * 大数据技术交流群:376932160
- * **/
- public class HiveJDBClient {
- /**Hive的驱动字符串*/
- private static String driver="org.apache.hive.jdbc.HiveDriver";
- public static void main(String[] args) throws Exception{
- //加载Hive驱动
- Class.forName(driver);
- //获取hive2的jdbc连接,注意默认的数据库是default
- Connection conn=DriverManager.getConnection("jdbc:hive2://192.168.46.32/default", "search", "dongliang");
- Statement st=conn.createStatement();
- String tableName="mytt";//表名
- ResultSet rs=st.executeQuery("select avg(count) from "+tableName+" ");//求平均数,会转成MapReduce作业运行
- //ResultSet rs=st.executeQuery("select * from "+tableName+" ");//查询所有,直接运行
- while(rs.next()){
- System.out.println(rs.getString(1)+" ");
- }
- System.out.println("成功!");
- st.close();
- conn.close();
- }
- }
package com.test; import java.sql.Connection; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.Statement; import org.apache.hadoop.conf.Configuration; /** * 在Win7上,使用JDBC操作Hive * @author qindongliang * * 大数据技术交流群:376932160 * **/ public class HiveJDBClient { /**Hive的驱动字符串*/ private static String driver="org.apache.hive.jdbc.HiveDriver"; public static void main(String[] args) throws Exception{ //加载Hive驱动 Class.forName(driver); //获取hive2的jdbc连接,注意默认的数据库是default Connection conn=DriverManager.getConnection("jdbc:hive2://192.168.46.32/default", "search", "dongliang"); Statement st=conn.createStatement(); String tableName="mytt";//表名 ResultSet rs=st.executeQuery("select avg(count) from "+tableName+" ");//求平均数,会转成MapReduce作业运行 //ResultSet rs=st.executeQuery("select * from "+tableName+" ");//查询所有,直接运行 while(rs.next()){ System.out.println(rs.getString(1)+" "); } System.out.println("成功!"); st.close(); conn.close(); } }
结果如下:
- 48.6
- 成功!
48.6 成功!
Hive的hiveserver2 端log打印日志:
- [search@h1 bin]$ ./hiveserver2
- Starting HiveServer2
- 14/08/05 04:00:02 INFO Configuration.deprecation: mapred.reduce.tasks is deprecated. Instead, use mapreduce.job.reduces
- 14/08/05 04:00:02 INFO Configuration.deprecation: mapred.min.split.size is deprecated. Instead, use mapreduce.input.fileinputformat.split.minsize
- 14/08/05 04:00:02 INFO Configuration.deprecation: mapred.reduce.tasks.speculative.execution is deprecated. Instead, use mapreduce.reduce.speculative
- 14/08/05 04:00:02 INFO Configuration.deprecation: mapred.min.split.size.per.node is deprecated. Instead, use mapreduce.input.fileinputformat.split.minsize.per.node
- 14/08/05 04:00:02 INFO Configuration.deprecation: mapred.input.dir.recursive is deprecated. Instead, use mapreduce.input.fileinputformat.input.dir.recursive
- 14/08/05 04:00:02 INFO Configuration.deprecation: mapred.min.split.size.per.rack is deprecated. Instead, use mapreduce.input.fileinputformat.split.minsize.per.rack
- 14/08/05 04:00:02 INFO Configuration.deprecation: mapred.max.split.size is deprecated. Instead, use mapreduce.input.fileinputformat.split.maxsize
- 14/08/05 04:00:02 INFO Configuration.deprecation: mapred.committer.job.setup.cleanup.needed is deprecated. Instead, use mapreduce.job.committer.setup.cleanup.needed
- 14/08/05 04:00:02 WARN conf.HiveConf: DEPRECATED: Configuration property hive.metastore.local no longer has any effect. Make sure to provide a valid value for hive.metastore.uris if you are connecting to a remote metastore.
- OK
- OK
- Total jobs = 1
- Launching Job 1 out of 1
- Number of reduce tasks determined at compile time: 1
- In order to change the average load for a reducer (in bytes):
- set hive.exec.reducers.bytes.per.reducer=<number>
- In order to limit the maximum number of reducers:
- set hive.exec.reducers.max=<number>
- In order to set a constant number of reducers:
- set mapreduce.job.reduces=<number>
- Starting Job = job_1407179651448_0001, Tracking URL = http://h1:8088/proxy/application_1407179651448_0001/
- Kill Command = /home/search/hadoop/bin/hadoop job -kill job_1407179651448_0001
- Hadoop job information for Stage-1: number of mappers: 1; number of reducers: 1
- 2014-08-05 04:03:49,951 Stage-1 map = 0%, reduce = 0%
- 2014-08-05 04:04:19,118 Stage-1 map = 100%, reduce = 0%, Cumulative CPU 2.74 sec
- 2014-08-05 04:04:30,860 Stage-1 map = 100%, reduce = 100%, Cumulative CPU 3.7 sec
- MapReduce Total cumulative CPU time: 3 seconds 700 msec
- Ended Job = job_1407179651448_0001
- MapReduce Jobs Launched:
- Job 0: Map: 1 Reduce: 1 Cumulative CPU: 3.7 sec HDFS Read: 253 HDFS Write: 5 SUCCESS
- Total MapReduce CPU Time Spent: 3 seconds 700 msec
- OK
[search@h1 bin]$ ./hiveserver2 Starting HiveServer2 14/08/05 04:00:02 INFO Configuration.deprecation: mapred.reduce.tasks is deprecated. Instead, use mapreduce.job.reduces 14/08/05 04:00:02 INFO Configuration.deprecation: mapred.min.split.size is deprecated. Instead, use mapreduce.input.fileinputformat.split.minsize 14/08/05 04:00:02 INFO Configuration.deprecation: mapred.reduce.tasks.speculative.execution is deprecated. Instead, use mapreduce.reduce.speculative 14/08/05 04:00:02 INFO Configuration.deprecation: mapred.min.split.size.per.node is deprecated. Instead, use mapreduce.input.fileinputformat.split.minsize.per.node 14/08/05 04:00:02 INFO Configuration.deprecation: mapred.input.dir.recursive is deprecated. Instead, use mapreduce.input.fileinputformat.input.dir.recursive 14/08/05 04:00:02 INFO Configuration.deprecation: mapred.min.split.size.per.rack is deprecated. Instead, use mapreduce.input.fileinputformat.split.minsize.per.rack 14/08/05 04:00:02 INFO Configuration.deprecation: mapred.max.split.size is deprecated. Instead, use mapreduce.input.fileinputformat.split.maxsize 14/08/05 04:00:02 INFO Configuration.deprecation: mapred.committer.job.setup.cleanup.needed is deprecated. Instead, use mapreduce.job.committer.setup.cleanup.needed 14/08/05 04:00:02 WARN conf.HiveConf: DEPRECATED: Configuration property hive.metastore.local no longer has any effect. Make sure to provide a valid value for hive.metastore.uris if you are connecting to a remote metastore. OK OK Total jobs = 1 Launching Job 1 out of 1 Number of reduce tasks determined at compile time: 1 In order to change the average load for a reducer (in bytes): set hive.exec.reducers.bytes.per.reducer=<number> In order to limit the maximum number of reducers: set hive.exec.reducers.max=<number> In order to set a constant number of reducers: set mapreduce.job.reduces=<number> Starting Job = job_1407179651448_0001, Tracking URL = http://h1:8088/proxy/application_1407179651448_0001/ Kill Command = /home/search/hadoop/bin/hadoop job -kill job_1407179651448_0001 Hadoop job information for Stage-1: number of mappers: 1; number of reducers: 1 2014-08-05 04:03:49,951 Stage-1 map = 0%, reduce = 0% 2014-08-05 04:04:19,118 Stage-1 map = 100%, reduce = 0%, Cumulative CPU 2.74 sec 2014-08-05 04:04:30,860 Stage-1 map = 100%, reduce = 100%, Cumulative CPU 3.7 sec MapReduce Total cumulative CPU time: 3 seconds 700 msec Ended Job = job_1407179651448_0001 MapReduce Jobs Launched: Job 0: Map: 1 Reduce: 1 Cumulative CPU: 3.7 sec HDFS Read: 253 HDFS Write: 5 SUCCESS Total MapReduce CPU Time Spent: 3 seconds 700 msec OK
hadoop的8088界面截图如下:
下面这条SQL语句,不会转成MapReduce执行,select * from mytt limit 3;
结果如下:
- 中国
- 美国
- 中国
- 成功!
中国 美国 中国 成功!
至此,我们的JDBC调用Hive已经成功运行,我们可以在客户端执行,一些建表,建库,查询等操作,但是有一点需要注意的是,如果在win上对Hive的表,执行数据导入表的操作,那么一定确保你的数据是在linux上的,导入的路径也是linux路径,不能直接把win下面的数据,给导入到linux上的hive表里面