使用 JDBC 从 Java 连接到 Hive [英] Connect from Java to Hive using JDBC

问题描述

我正在尝试从 Java 连接到 Hive 服务器 1.我之前在这个论坛上发现了一个问题，但它对我不起作用.我正在使用此代码:

I'm trying to connect from Java to Hive server 1. I found a question time ago in this forum but it doesn't work for me. I'm using this code:

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.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);
    }
    //replace "hive" here with the name of the user the queries should run as
    Connection con = DriverManager.getConnection("jdbc:hive2://localhost:10000/default", "hive", "");
    Statement stmt = con.createStatement();
    String tableName = "testHiveDriverTable";
    stmt.execute("drop table if exists " + tableName);
    stmt.execute("create table " + tableName + " (key int, value string)");
    // show tables
    String sql = "show tables '" + tableName + "'";
    System.out.println("Running: " + sql);
    ResultSet 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) + "	" + 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);
stmt.execute(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)) + "	" + 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));
}

这是指南中显示的代码.我在 .java 的同一路径中复制了 hive-metastore、service、jdbc、exec、core 和更多 .jar.当我编译它时，我得到这个消息:

That's the code shown in the guide. I've copied hive-metastore, service, jdbc, exec, core and more .jar in the same path of the .java. When I compile it, I get this msg:

java.lang.ClassNotFoundException: org.apache.hadoop.hive.jdbc.HiveDriver
    at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Class.java:190)
    at HiveJdbcClient.main(HiveJdbcClient.java:14)

有人知道这里发生了什么吗?

Does anybody know what's happening here?

推荐答案

尝试

private static String driverName = "org.apache.hive.jdbc.HiveDriver"

代替

private static String driverName = "org.apache.hadoop.hive.jdbc.HiveDriver";

希望您在代码中添加了 Class.forName(driverName) 语句

I hope you have added Class.forName(driverName) statement in your code

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