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ApacheHive一点一点进步(2)–HIVEJDBC

程序员文章站 2022-04-20 13:48:04
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Hive提供了多种方式进行数据的访问。其中对 java 的支持是最好的,而且是其最原生的支持。传说中的JDBC。哈哈! 在 hive 安装目录下的lib目录中有 hive - jdbc -0.8.1.jar 。以0.8版本的为例来介绍。 当然了,也别忘了要通过hive的server方式将hive启动起来

Hive提供了多种方式进行数据的访问。其中对java的支持是最好的,而且是其最原生的支持。传说中的JDBC。哈哈!

hive安装目录下的lib目录中有hive-jdbc-0.8.1.jar 。以0.8版本的为例来介绍。

当然了,也别忘了要通过hive的server方式将hive启动起来。命令就不在这里介绍了。

以下是官网提供的一段示例,使用起来比较简单。client端支持的语法在这里都是支持的。

而且可以通过这个进行环境变量设置,这个设置并不会影响server端,只在本次会话中生效,所以不用担心任务间影响。

Java

import java.sql.SQLException;import java.sql.Connection;import java.sql.ResultSet;import java.sql.Statement;import java.sql.DriverManager; public class HiveJdbcClient {  private static String driverName = "org.apache.hadoop.hive.jdbc.HiveDriver";   /** * @param args * @throws SQLException   */  public static void main(String[] args) throws SQLException {      try {      Class.forName(driverName);    } catch (ClassNotFoundException e) {      // TODO Auto-generated catch block      e.printStackTrace();      System.exit(1);    }    Connection con = DriverManager.getConnection("jdbc:hive://localhost:10000/default", "", "");    Statement stmt = con.createStatement();    String tableName = "testHiveDriverTable";    stmt.executeQuery("drop table " + tableName);    ResultSet res = stmt.executeQuery("create table " + tableName + " (key int, value string)");    // show tables    String sql = "show tables '" + tableName + "'";    System.out.println("Running: " + sql);    res = stmt.executeQuery(sql);    if (res.next()) {      System.out.println(res.getString(1));    }    // describe table    sql = "describe " + tableName;    System.out.println("Running: " + sql);    res = stmt.executeQuery(sql);    while (res.next()) {      System.out.println(res.getString(1) + "\t" + res.getString(2));    }     // load data into table    // NOTE: filepath has to be local to the hive server    // NOTE: /tmp/a.txt is a ctrl-A separated file with two fields per line    String filepath = "/tmp/a.txt";    sql = "load data local inpath '" + filepath + "' into table " + tableName;    System.out.println("Running: " + sql);    res = stmt.executeQuery(sql);     // select * query    sql = "select * from " + tableName;    System.out.println("Running: " + sql);    res = stmt.executeQuery(sql);    while (res.next()) {      System.out.println(String.valueOf(res.getInt(1)) + "\t" + res.getString(2));    }     // regular hive query    sql = "select count(1) from " + tableName;    System.out.println("Running: " + sql);    res = stmt.executeQuery(sql);    while (res.next()) {      System.out.println(res.getString(1));    }  }}

Python

#!/usr/bin/env python import sys from hive import ThriftHivefrom hive.ttypes import HiveServerExceptionfrom thrift import Thriftfrom thrift.transport import TSocketfrom thrift.transport import TTransportfrom thrift.protocol import TBinaryProtocol try:    transport = TSocket.TSocket('localhost', 10000)    transport = TTransport.TBufferedTransport(transport)    protocol = TBinaryProtocol.TBinaryProtocol(transport)     client = ThriftHive.Client(protocol)    transport.open()     client.execute("CREATE TABLE r(a STRING, b INT, c DOUBLE)")    client.execute("LOAD TABLE LOCAL INPATH '/path' INTO TABLE r")    client.execute("SELECT * FROM r")    while (1):      row = client.fetchOne()      if (row == None):        break      print row    client.execute("SELECT * FROM r")    print client.fetchAll()     transport.close() except Thrift.TException, tx:    print '%s' % (tx.message)

PHP

open(); // run queries, metadata calls etc$client->execute('SELECT * from src');var_dump($client->fetchAll());$transport->close();