网上找了很多封装的API,发现都是过时了的,运行报各种错误,经过了几天的调错,终于可以使用java代码操作hive了
首先看看所需的包
所有的分析都在代码里面
注意:网上很多代码对于DDL都执行 res = stmt.executeQuery(sql); 这是错的,因为新版本DDL不能返回结果集,会报如下错误 java.sql.SQLException: The query did not generate a result set! 所以只能写 stmt.execute(sql); 它会返回一个boolean值 只有对于DML才能返回结果集 具体看下面的代码大家就懂了,不信的话大家可以试试,我的是1.1.1版本
package com.berg.hive.test1.api; 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; /** * Hive的JavaApi * * 启动hive的远程服务接口命令行执行:hive --service hiveserver & * * @author 汤高 * */ public class HiveJdbcCli { //网上写 org.apache.hadoop.hive.jdbc.HiveDriver ,新版本不能这样写 private static String driverName = "org.apache.hive.jdbc.HiveDriver"; //这里是hive2,网上其他人都写hive,在高版本中会报错 private static String url = "jdbc:hive2://master:10000/default"; private static String user = "hive"; private static String password = "hive"; private static String sql = ""; private static ResultSet res; private static final Logger log = Logger.getLogger(HiveJdbcCli.class); public static void main(String[] args) { Connection conn = null; Statement stmt = null; try { conn = getConn(); stmt = conn.createStatement(); // 第一步:存在就先删除 String tableName = dropTable(stmt); // 第二步:不存在就创建 createTable(stmt, tableName); // 第三步:查看创建的表 showTables(stmt, tableName); // 执行describe table操作 describeTables(stmt, tableName); // 执行load data into table操作 loadData(stmt, tableName); // 执行 select * query 操作 selectData(stmt, tableName); // 执行 regular hive query 统计操作 countData(stmt, tableName); } 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); } finally { try { if (conn != null) { conn.close(); conn = null; } if (stmt != null) { stmt.close(); stmt = null; } } catch (SQLException e) { e.printStackTrace(); } } } private static void countData(Statement stmt, String tableName) throws SQLException { 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("count ------>" + res.getString(1)); } } private static void selectData(Statement stmt, String tableName) throws SQLException { 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)); } } private static void loadData(Statement stmt, String tableName) throws SQLException { //目录 ,我的是hive安装的机子的虚拟机的home目录下 String filepath = "user.txt"; sql = "load data local inpath '" + filepath + "' into table " + tableName; System.out.println("Running:" + sql); stmt.execute(sql); } private static void describeTables(Statement stmt, String tableName) throws SQLException { 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)); } } private static void showTables(Statement stmt, String tableName) throws SQLException { 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)); } } private static void createTable(Statement stmt, String tableName) throws SQLException { sql = "create table " + tableName + " (key int, value string) row format delimited fields terminated by '\t'"; stmt.execute(sql); } private static String dropTable(Statement stmt) throws SQLException { // 创建的表名 String tableName = "testHive"; sql = "drop table " + tableName; stmt.execute(sql); return tableName; } private static Connection getConn() throws ClassNotFoundException, SQLException { Class.forName(driverName); Connection conn = DriverManager.getConnection(url, user, password); return conn; } }
转载请指明出处 http://blog.csdn.net/tanggao1314/article/details/51510844
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