实战1——Hive与JDBC示例

在使用 JDBC 开发 Hive 程序时,  必须首先开启 Hive 的远程服务接口。使用下面命令进行开启:

hive -service hiveserver &

1). 测试数据
userinfo.txt文件内容(每行数据之间用tab键隔开):

1    xiapi
2    xiaoxue
3    qingqing

2). 程序代码

package com.ljq.hive;

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

import org.apache.log4j.Logger;

public class HiveJdbcClient {
        private static String driverName = "org.apache.hadoop.hive.jdbc.HiveDriver";
        private static String url = "jdbc:hive://192.168.11.157:10000/default";
        private static String user = "hive";
        private static String password = "mysql";
        private static String sql = "";
        private static ResultSet res;
        private static final Logger log = Logger.getLogger(HiveJdbcClient.class);

        public static void main(String[] args) {
                try {
                        Class.forName(driverName);
                        Connection conn = DriverManager.getConnection(url, user, password);
                        Statement stmt = conn.createStatement();

                        // 创建的表名
                        String tableName = "testHiveDriverTable";
                        /** 第一步:存在就先删除 **/
                        sql = "drop table " + tableName;
                        stmt.executeQuery(sql);

                        /** 第二步:不存在就创建 **/
                        sql = "create table " + tableName + " (key int, value string)  row format delimited fields terminated by '\t'";
                        stmt.executeQuery(sql);

                        // 执行“show tables”操作
                        sql = "show tables '" + tableName + "'";
                        System.out.println("Running:" + sql);
                        res = stmt.executeQuery(sql);
                        System.out.println("执行“show tables”运行结果:");
                        if (res.next()) {
                                System.out.println(res.getString(1));
                        }

                        // 执行“describe table”操作
                        sql = "describe " + tableName;
                        System.out.println("Running:" + sql);
                        res = stmt.executeQuery(sql);
                        System.out.println("执行“describe table”运行结果:");
                        while (res.next()) {  
                                System.out.println(res.getString(1) + "\t" + res.getString(2));
                        }

                        // 执行“load data into table”操作
                        String filepath = "/home/hadoop/ziliao/userinfo.txt";
                        sql = "load data local inpath '" + filepath + "' into table " + tableName;
                        System.out.println("Running:" + sql);
                        res = stmt.executeQuery(sql);
                        
                        // 执行“select * query”操作
                        sql = "select * from " + tableName;
                        System.out.println("Running:" + sql);
                        res = stmt.executeQuery(sql);
                        System.out.println("执行“select * query”运行结果:");
                        while (res.next()) {
                                System.out.println(res.getInt(1) + "\t" + res.getString(2));
                        }

                        // 执行“regular hive query”操作
                        sql = "select count(1) from " + tableName;
                        System.out.println("Running:" + sql);
                        res = stmt.executeQuery(sql);
                        System.out.println("执行“regular hive query”运行结果:");
                        while (res.next()) {
                                System.out.println(res.getString(1));

                        }

                        conn.close();
                        conn = null;
                } catch (ClassNotFoundException e) {
                        e.printStackTrace();
                        log.error(driverName + " not found!", e);
                        System.exit(1);
                } catch (SQLException e) {
                        e.printStackTrace();
                        log.error("Connection error!", e);
                        System.exit(1);
                }

        }
}

3). 运行结果(右击-->Run as-->Run on Hadoop)

Running:show tables 'testHiveDriverTable'
执行“show tables”运行结果:
testhivedrivertable
Running:describe testHiveDriverTable
执行“describe table”运行结果:
key    int
value    string
Running:load data local inpath '/home/hadoop/ziliao/userinfo.txt' into table testHiveDriverTable
Running:select * from testHiveDriverTable
执行“select * query”运行结果:
1    xiapi
2    xiaoxue
3    qingqing
Running:select count(1) from testHiveDriverTable
执行“regular hive query”运行结果:
3