HiveServer2 JDBC客户端连接Hive数据库

1. 介绍：

• 两者都允许远程客户端使用多种编程语言，通过HiveServer或者HiveServer2，客户端可以在不启动CLI的情况下对Hive中的数据进行操作，两者都允许远程客户端使用多种编程语言如java，python等向hive提交请求，取回结果（从hive0.15起就不再支持hiveserver了），但是在这里我们还是要说一下hiveserver

• HiveServer或者HiveServer2都是基于Thrift的，但HiveSever有时被称为Thrift server，而HiveServer2却不会。既然已经存在HiveServer，为什么还需要HiveServer2呢？这是因为HiveServer不能处理多于一个客户端的并发请求，这是由于HiveServer使用的Thrift接口所导致的限制，不能通过修改HiveServer的代码修正。因此在Hive-0.11.0版本中重写了HiveServer代码得到了HiveServer2，进而解决了该问题。HiveServer2支持多客户端的并发和认证，为开放API客户端如JDBC、ODBC提供更好的支持。

2. 启动hiveserver2

    1. [hadoop@wjxhadoop001 ~]$ cd /opt/software/hive/bin/
    2. [hadoop@wjxhadoop001 bin]$ hiveserver2 
    3. which: no hbase in (/opt/software/hive/bin:/opt/software/hadoop/sbin:/opt/software/hadoop/bin:/opt/software/apache-maven-3.3.9/bin:/usr/java/jdk1.8.0_45/bin:/usr/lib64/qt-3.3/bin:/usr/local/bin:/bin:/usr/bin:/usr/local/sbin:/usr/sbin:/sbin:/home/hadoop/bin)

3. 连接JDBC

    1. [hadoop@wjxhadoop001 bin]$ ./beeline -u jdbc:hive2://localhost:10000/default -n hadoop

    2. which: no hbase in (/opt/software/hive/bin:/opt/software/hadoop/sbin:/opt/software/hadoop/bin:/opt/software/apache-maven-3.3.9/bin:/usr/java/jdk1.8.0_45/bin:/usr/lib64/qt-3.3/bin:/usr/local/bin:/bin:/usr/bin:/usr/local/sbin:/usr/sbin:/sbin:/home/hadoop/bin)
    3. scan complete in 4ms
    4. Connecting to jdbc:hive2://localhost:10000/default
    5. Connected to: Apache Hive (version 1.1.0-cdh5.7.0)
    6. Driver: Hive JDBC (version 1.1.0-cdh5.7.0)
    7. Transaction isolation: TRANSACTION_REPEATABLE_READ
    8. Beeline version 1.1.0-cdh5.7.0 by Apache Hive
    9. 0: jdbc:hive2://localhost:10000/default>

• 使用SQL

  1. 0: jdbc:hive2://localhost:10000/default> show databases;
  2. INFO  : Compiling command(queryId=hadoop_20180114082525_e8541a4a-e849-4017-9dab-ad5162fa74c1): show databases
  3. INFO  : Semantic Analysis Completed
  4. INFO  : Returning Hive schema: Schema(fieldSchemas:[FieldSchema(name:database_name, type:string, comment:from deserializer)], properties:null)
  5. INFO  : Completed compiling command(queryId=hadoop_20180114082525_e8541a4a-e849-4017-9dab-ad5162fa74c1); Time taken: 0.478 seconds
  6. INFO  : Concurrency mode is disabled, not creating a lock manager
  7. INFO  : Executing command(queryId=hadoop_20180114082525_e8541a4a-e849-4017-9dab-ad5162fa74c1): show databases
  8. INFO  : Starting task [Stage-0:DDL] in serial mode
  9. INFO  : Completed executing command(queryId=hadoop_20180114082525_e8541a4a-e849-4017-9dab-ad5162fa74c1); Time taken: 0.135 seconds
  10. INFO  : OK
  11. +----------------+--+
  12. | database_name  |
  13. +----------------+--+
  14. | default        |
  15. +----------------+--+
  16.1 row selected      
  

• 编写java代码

  1. import java.sql.Connection;
  2. import java.sql.DriverManager;
  3. import java.sql.ResultSet;
  4. import java.sql.Statement;
  
  5. public class JdbcApp {
  6.     private static String driverName = "org.apache.hive.jdbc.HiveDriver";
  
  7.     public static void main(String[] args) throws Exception {
  8.         try {
  9.             Class.forName(driverName);
  10.         } catch (ClassNotFoundException e) {
  11.             // TODO Auto-generated catch block
  12.             e.printStackTrace();
  13.             System.exit(1);
  14.         }
  15.         Connection con = DriverManager.getConnection("jdbc:hive2://192.168.137.200:10000/default", "", "");
  16.         Statement stmt = con.createStatement();
  
  17.        //select table:ename
  18.         String tableName = "emp";
  19.         String sql = "select ename from " + tableName;
  20.         System.out.println("Running: " + sql);
  21.         ResultSet res = stmt.executeQuery(sql);
  22.          while(res.next()) {
  23.             System.out.println(res.getString(1));
  24.         }
  25.         // describe table
  26.         sql = "describe " + tableName;
  27.         System.out.println("Running: " + sql);
  28.         res = stmt.executeQuery(sql);
  29.         while (res.next()) {
  30.             System.out.println(res.getString(1) + "\t" + res.getString(2));
  31.         }
  32.     }
  33. }
  

4. 默认参数

• Hiveserver2允许在配置文件hive-site.xml中进行配置管理，具体的参数为：

  1. hive.server2.thrift.min.worker.threads– 最小工作线程数，默认为5。  
  2. hive.server2.thrift.max.worker.threads – 最小工作线程数，默认为500。  
  3. hive.server2.thrift.port– TCP 的监听端口，默认为10000。  
  4. hive.server2.thrift.bind.host– TCP绑定的主机，默认为localhost 
  

• 配置监听端口和路径

  1.  sudo vi hive-site.xml
  2. 
  3.   hive.server2.thrift.port
  4.   10000
  5. 
  6. 
  7.   hive.server2.thrift.bind.host
  8.   192.168.48.130
  9. 
  

来自@若泽大数据