Maven hive-jdbc教程

由于项目中需要用到hive-jdbc从数据仓库拉数据下来，所以简单的学一下hive，hive数据仓库建构在hadoop集群之上，数据存在hdfs文件系统中，hive中执行的操作会装换成mapreduce作业进行执行，hive支持类似SQL的语言HQL，hive采用元数据对表进行管理，元数据有三种存放模式：嵌入模式，远程模式，本地模式；hive提供了强大的编程接口，hive jdbc可以让你如使用普通的jdbc一般来操作hive表以及数据。

1.添加依赖

        <dependency>
			<groupId>org.apache.hadoop</groupId>
			<artifactId>hadoop-hdfs</artifactId>
			<version>2.6.4</version>
		</dependency>

		<dependency>
			<groupId>org.apache.hadoop</groupId>
			<artifactId>hadoop-common</artifactId>
			<version>2.6.4</version>
		</dependency>

		<dependency>
			<groupId>org.apache.hive</groupId>
			<artifactId>hive-exec</artifactId>
			<version>1.1.0</version>
			<exclusions>
				<exclusion>
					<artifactId>
						pentaho-aggdesigner-algorithm
					</artifactId>
					<groupId>org.pentaho</groupId>
				</exclusion>
			</exclusions>
		</dependency>

		<dependency>
			<groupId>org.apache.hive</groupId>
			<artifactId>hive-jdbc</artifactId>
			<version>1.1.0</version>
		</dependency>

2.jdbc连接hive

public class TestHive {
        private static String driverName = "org.apache.hive.jdbc.HiveDriver";//jdbc驱动路径
        private static String url = "jdbc:hive2://hiveserver.xxx.com:10000/dbName";//hive库地址+库名
        private static String user = "username";//用户名
        private static String password = "pwd";//密码
        private static String sql = "";
        private static ResultSet res;

        public static void main(String[] args) {
		Connection conn = null;
		Statement stmt = null;
		try {
			conn = getConn();
			System.out.println(conn);
			stmt = conn.createStatement();
                        String tableName="tab_name";//hive表名
                        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));
		        }

		} catch (ClassNotFoundException e) {
			e.printStackTrace();
			System.exit(1);
		} catch (SQLException e) {
			e.printStackTrace();
			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 Connection getConn() throws ClassNotFoundException,
			SQLException {
		Class.forName(driverName);
		Connection conn = DriverManager.getConnection(url, user, password);
		return conn;
	}
}

3.查询hive表数据

这个就和普通的jdbc差不太多，也是用sql的方式进行查询，具体的查询语法，可以参考hive官网

4.封装hive工具类

写完了再贴上来

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