前言
在前面的章节内, 我们介绍了Hive的安装、远程链接和基本使用. 本章, 我们介绍下如何在Java内完成这些操作.
正文
- pom.xml 文件
<dependencies>
<dependency>
<groupId>org.apache.hive</groupId>
<artifactId>hive-jdbc</artifactId>
<version>2.3.4</version>
<!-- <exclusions>
<exclusion>
<groupId>org.apache.hive</groupId>
<artifactId>hive-service-rpc</artifactId>
</exclusion>
<exclusion>
<groupId>org.apache.hive</groupId>
<artifactId>hive-service</artifactId>
</exclusion>
</exclusions> -->
</dependency>
<dependency>
<groupId>org.apache.hadoop</groupId>
<artifactId>hadoop-common</artifactId>
<version>2.7.5</version>
</dependency>
<dependency>
<groupId>org.apache.hadoop</groupId>
<artifactId>hadoop-hdfs</artifactId>
<version>2.7.5</version>
</dependency>
<dependency>
<groupId>org.apache.hadoop</groupId>
<artifactId>hadoop-mapreduce-client-jobclient</artifactId>
<version>2.7.5</version>
</dependency>
<dependency>
<groupId>org.apache.hive</groupId>
<artifactId>hive-exec</artifactId>
<version>2.3.4</version>
</dependency>
<dependency>
<groupId>org.apache.hive</groupId>
<artifactId>hive-jdbc</artifactId>
<version>2.3.4</version>
</dependency>
<dependency>
<groupId>org.apache.hive</groupId>
<artifactId>hive-cli</artifactId>
<version>2.3.4</version>
</dependency>
<dependency>
<groupId>org.apache.hive</groupId>
<artifactId>hive-common</artifactId>
<version>2.3.4</version>
</dependency>
<dependency>
<groupId>org.apache.hive</groupId>
<artifactId>hive-metastore</artifactId>
<version>2.3.4</version>
</dependency>
<dependency>
<groupId>org.apache.hive</groupId>
<artifactId>hive-service</artifactId>
<version>2.3.4</version>
</dependency>
<!-- <dependency>
<groupId>org.apache.hive</groupId>
<artifactId>hive-service</artifactId>
<version>2.3.4</version>
</dependency> -->
<!-- https://mvnrepository.com/artifact/junit/junit -->
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
<scope>test</scope>
</dependency>
</dependencies>
基本API:
- 创建链接
private static String driverName = "org.apache.hive.jdbc.HiveDriver";
private static String url = "jdbc:hive2://localhost:10000";
private static String user = "Hadoop";
private static String password = "123456";
private static Connection conn = null;
private static Statement stmt = null;
private static ResultSet rs = null;
// 加载驱动、创建连接
@Before
public void init() throws Exception {
Class.forName(driverName);
conn = DriverManager.getConnection(url,user,password);
stmt = conn.createStatement();
}
- 创建所有库
// 创建数据库
@Test
public void createDatabase() throws Exception {
String sql = "create database hive_jdbc_test";
System.out.println("Running: " + sql);
stmt.execute(sql);
}
- 查询所有数据库
// 查询所有数据库
@Test
public void showDatabases() throws Exception {
String sql = "show databases";
System.out.println("Running: " + sql);
rs = stmt.executeQuery(sql);
while (rs.next()) {
System.out.println(rs.getString(1));
}
}
- 创建表
// 创建表
@Test
public void createTable() throws Exception {
String sql = "create table emp(\n" +
"empno int,\n" +
"ename string,\n" +
"job string,\n" +
"mgr int,\n" +
"hiredate string,\n" +
"sal double,\n" +
"comm double,\n" +
"deptno int\n" +
")\n" +
"row format delimited fields terminated by '\\t'";
System.out.println("Running: " + sql);
stmt.execute(sql);
}
- 查看所有表
// 查询所有表
@Test
public void showTables() throws Exception {
String sql = "show tables";
System.out.println("Running: " + sql);
rs = stmt.executeQuery(sql);
while (rs.next()) {
System.out.println(rs.getString(1));
}
}
- 查看表结构
// 查看表结构
@Test
public void descTable() throws Exception {
String sql = "desc emp";
System.out.println("Running: " + sql);
rs = stmt.executeQuery(sql);
while (rs.next()) {
System.out.println(rs.getString(1) + "\t" + rs.getString(2));
}
}
- 加载数据(插入数据)
// 加载数据
@Test
public void loadData() throws Exception {
String filePath = "/home/hadoop/data/emp.txt";
String sql = "load data local inpath '" + filePath + "' overwrite into table emp";
System.out.println("Running: " + sql);
stmt.execute(sql);
}
- 查询数据
// 查询数据
@Test
public void selectData() throws Exception {
String sql = "select * from emp";
System.out.println("Running: " + sql);
rs = stmt.executeQuery(sql);
System.out.println("员工编号" + "\t" + "员工姓名" + "\t" + "工作岗位");
while (rs.next()) {
System.out.println(rs.getString("empno") + "\t\t" + rs.getString("ename") + "\t\t" + rs.getString("job"));
}
}
- 统计计算
// 统计查询（会运行mapreduce作业）
@Test
public void countData() throws Exception {
String sql = "select count(1) from emp";
System.out.println("Running: " + sql);
rs = stmt.executeQuery(sql);
while (rs.next()) {
System.out.println(rs.getInt(1) );
}
}
- 删除数据库
// 删除数据库
@Test
public void dropDatabase() throws Exception {
String sql = "drop database if exists hive_jdbc_test";
System.out.println("Running: " + sql);
stmt.execute(sql);
}
- 删除数据库表
// 删除数据库表
@Test
public void deopTable() throws Exception {
String sql = "drop table if exists emp";
System.out.println("Running: " + sql);
stmt.execute(sql);
}
- 释放资源
// 释放资源
@After
public void destory() throws Exception {
if ( rs != null) {
rs.close();
}
if (stmt != null) {
stmt.close();
}
if (conn != null) {
conn.close();
}
}
Reference
[1]. Hive 之 Java API 操作
[2]. Hive 使用Jdbc连接进行连接
[3]. (Official) HiveServer2 Clients
原文地址：https://blog.csdn.net/u010416101/article/details/89198779
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