Question

我想使用java代码连接MetaStore。我不知道如何在Hive-Site.xml文件中设置配置设置以及我将发布Hive-Site.xml文件的位置。请帮忙。

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;

import org.apache.hadoop.fs.Path;
import org.apache.hadoop.hive.conf.HiveConf;
import org.apache.hadoop.hive.conf.HiveConf.ConfVars;

public class HiveMetastoreJDBCTest {

    public static void main(String[] args) throws Exception {

        Connection conn = null;
        try {
            HiveConf conf = new HiveConf();
            conf.addResource(new Path("file:///path/to/hive-site.xml"));
            Class.forName(conf.getVar(ConfVars.METASTORE_CONNECTION_DRIVER));
            conn = DriverManager.getConnection(
                    conf.getVar(ConfVars.METASTORECONNECTURLKEY),
                    conf.getVar(ConfVars.METASTORE_CONNECTION_USER_NAME),
                    conf.getVar(ConfVars.METASTOREPWD));

            Statement st = conn.createStatement();
            ResultSet rs = st.executeQuery(
                "select t.tbl_name, s.location from tbls t " +
                "join sds s on t.sd_id = s.sd_id");
            while (rs.next()) {
                System.out.println(rs.getString(1) + " : " + rs.getString(2));
            }
        }        

    }
}

Answer 1

在 hive-site.xml 中添加以下行：

<property>
  <name>hive.metastore.local</name>
  <value>true</value>
</property>
<property>
  <name>javax.jdo.option.ConnectionURL</name>
  <value>jdbc:mysql://localhost:3306/hive</value>
</property>
<property>
  <name>javax.jdo.option.ConnectionUserName</name>
  <value>hiveuser</value>
</property>
<property>
  <name>javax.jdo.option.ConnectionPassword</name>
  <value>hivepass</value>
</property>

在jdbc:mysql://localhost:3306/hive中，3306是您的默认mysql端口; hive是hive Metastore的mysql数据库名称。将hiveuser更改为您的mysql配置单元用户名，将hivepass更改为您的mysql配置单元密码。

如果您还没有在mysql中为hive Metastore创建数据库，请在终端中执行此步骤：

mysql -u root -p

输入您的mysql root密码。

mysql> create database hive;

mysql> create user 'hiveuser'@'%' IDENTIFIED BY 'hivepass';

mysql> GRANT all on *.* to 'hiveuser'@localhost identified by 'hivepass';

mysql> flush privileges;

此处，hiveuser和hivepass分别是您为hive Metastore提供的用户名和密码。

注意：您需要在 $ HIVE_HOME / lib 中包含 mysql-jdbc-connector.jar ，的 $ HADOOP_HOME / lib中

Answer 2

关于Hive-site.xml，这里是我的测试机器的样本。这是用于在localhost上安装MySql服务器来设置hive Metastore。

<configuration>
<property>
 <name>javax.jdo.option.ConnectionURL</name>
 <value>jdbc:mysql://localhost/metastore?createDatabaseIfNotExist=true</value>
 <description>metadata is stored in a MySQL server</description>
</property>
<property>
 <name>javax.jdo.option.ConnectionDriverName</name>
 <value>com.mysql.jdbc.Driver</value>
 <description>MySQL JDBC driver class</description>
</property>
<property>
 <name>javax.jdo.option.ConnectionUserName</name>
 <value>hive</value>
 <description>user name for connecting to mysql server </description>
</property>
<property>
 <name>javax.jdo.option.ConnectionPassword</name>
 <value>123456</value>
 <description>password for connecting to mysql server </description>
</property>
</configuration>

您需要将此文件放在<system_path>/apache-hive-x.xx.x-bin/conf目录

中

我对如何在java中使用此文件不太了解。但是通过在java代码中指定连接字符串，您可以按照下面的方式执行

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class WriteToHive {
    private static String driverName = "org.apache.hadoop.hive.jdbc.HiveDriver";
    static Connection con;
    static Statement stmt;

    public WriteToHive() throws SQLException, ClassNotFoundException, Exception {
        try {
            Class.forName(driverName);
        } catch (ClassNotFoundException e){
            e.printStackTrace();
            throw new ClassNotFoundException("No JDBC Hive Driver found");
            //System.exit(1);
        } catch (Exception e) {
            e.printStackTrace();
            throw new Exception(e);
            //System.exit(1);
        }

        con = DriverManager.getConnection("jdbc:hive://localhost:10000/rajen","","");
        stmt = con.createStatement();
    }

    public static void main(String[] args) throws SQLException {
        try {
            Class.forName(driverName);
        } catch (ClassNotFoundException e){
            e.printStackTrace();
            System.exit(1);
        } catch (Exception e) {
            e.printStackTrace();
            System.exit(1);
        }
        con = DriverManager.getConnection("jdbc:hive://localhost:10000/rajen","","");
        stmt = con.createStatement();
        //Connection con = DriverManager.getConnection("jdbc:hive://","","");
        String tableName = "company_mas_hive_eclipse_trial";

        ResultSet res = stmt.executeQuery("use rajen");

        String sql = "DROP TABLE IF EXISTS " + tableName;
        System.out.println("Running: " + sql);
        res = stmt.executeQuery(sql);

        sql = "CREATE TABLE IF NOT EXISTS rajen.company_mas_hive_eclipse_trial (" +
              "Name string," + 
              "dateofincorporation string," + 
              "country string)" +
              "ROW FORMAT DELIMITED FIELDS TERMINATED BY \",\"";
        System.out.println("Running: " + sql);
        res = stmt.executeQuery(sql);

        sql = "show tables '" + tableName + "'";
        System.out.println("Running: " + sql);
        res = stmt.executeQuery(sql);

        if (res.next()){
            System.out.println(res.getString(1));
        }

        sql = "describe " + tableName;
        System.out.println("Running: " + sql);
        res = stmt.executeQuery(sql);
        System.out.println("=========================================");
        while (res.next()) {
          System.out.println(res.getString(1) + "\t" + res.getString(2));
        }
        System.out.println("=========================================");

        // 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 = "/home/seo/Refrence_Doc/sampledata/companymas"; //"/rajen/companymas";
        sql = "load data local inpath '" + filepath + "' into table " + tableName;
        System.out.println("Running: " + sql);
        res = stmt.executeQuery(sql);

        // 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
        filepath = "/rajen/companymas";
        sql = "load data 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.getString(1)) + "\t" + res.getString(2));
        }

        // regular hive query
        sql = "select count(*) from " + tableName;
        System.out.println("Running: " + sql);
        res = stmt.executeQuery(sql);
        while (res.next()) {
            System.out.println(res.getString(1));
        }
    }

    public void createTable(String def, String dbname) throws SQLException{
        @SuppressWarnings("unused")
        ResultSet res = stmt.executeQuery("use " + dbname);
        stmt.executeQuery(def);
    }

    public static void loadData(String filepath, String tableName) throws SQLException{
        stmt.executeQuery("load data local inpath '" + filepath + "' into table " + tableName);
    }
}

如何在Hive-Site.xml文件中设置hive Metastore连接的配置？

2 个答案: