hive的java客戶端
阿新 • • 發佈：2018-12-21
1.啟動hive
- (1)啟動hive
./hive --service hiveserver2 &
- (2)啟動beeline
#進入beeline命令列
./beeline
#連線hive的hiveserver2，按照提示輸入使用者名稱和密碼
beeline> !connect jdbc:hive2://192.168.1.222:10000
#檢視資料庫
0: jdbc:hive2://192.168.1.222:10000> show databases;
2.java客戶端
- (1)依賴
<?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>hadoop</groupId> <artifactId>1</artifactId> <version>1.0-SNAPSHOT</version> <dependencies> <!--hadoop--> <dependency> <groupId>org.apache.hadoop</groupId> <artifactId>hadoop-common</artifactId> <version>3.1.1</version> </dependency> <dependency> <groupId>org.apache.hadoop</groupId> <artifactId>hadoop-hdfs</artifactId> <version>3.1.1</version> </dependency> <dependency> <groupId>org.apache.hadoop</groupId> <artifactId>hadoop-client</artifactId> <version>3.1.1</version> </dependency> <dependency> <groupId>org.apache.hadoop</groupId> <artifactId>hadoop-assemblies</artifactId> <version>3.1.1</version> </dependency> <!--hbase--> <dependency> <groupId>org.apache.hbase</groupId> <artifactId>hbase-client</artifactId> <version>1.3.2</version> </dependency> <!--hive--> <dependency> <groupId>org.apache.hive</groupId> <artifactId>hive-jdbc</artifactId> <version>2.3.3</version> </dependency> </dependencies> </project>
- (2)測試類
由hiveSql提交的查詢語句將會解析成一個或多個mr程式，不包含聚合/連線的簡單select語句會使用一個只有m階段的job，使用group by的聚合查詢語句會使用一個獨立的mr程式，包含大量多表連線的複雜查詢會依靠多個mr查詢的順序執行來實現。
//DDL操作測試類 public class HiveClient { private static String driverName = "org.apache.hive.jdbc.HiveDriver"; private static String url = "jdbc:hive2://192.168.1.222:10000"; private static String user = "root"; private static String password = "123456"; private static Connection conn = null; private static Statement stmt = null; private static ResultSet rs = null; //初始化連線 static { try{ Class.forName(driverName); conn = DriverManager.getConnection(url,user,password); stmt = conn.createStatement(); } catch (Exception e){ e.printStackTrace(); } } //檢視資料庫 public void showDatabases() throws Exception{ String sql = "show databases"; System.out.println("查詢語句:" + sql); rs = stmt.executeQuery(sql); while (rs.next()) { System.out.println(rs.getString(1)); } } //建立資料庫 public void createDatabase(String dataBaseName) throws Exception{ String sql = "create database "+dataBaseName+""; System.out.println("查詢語句:" + sql); stmt.execute(sql); } //刪除資料庫 public void deleteDatabase(String dataBaseName) throws Exception{ String sql = "drop database if exists "+dataBaseName+""; System.out.println("查詢語句:" + sql); stmt.execute(sql); } //建立表 public void createTable(String tableName) throws Exception{ String sql = "create table "+tableName+"(\n" + "id int,\n" + "name string,\n" + "phone string,\n" + "age int\n" + ")\n" + "row format delimited "+ "fields terminated by '\\t'";//行記錄用tab分割屬性 System.out.println("查詢語句:"); System.out.println(sql); //stmt.execute(sql); } //查看錶結構 public void showTable(String tableName) throws Exception{ String sql = "desc "+tableName+""; System.out.println("查詢語句:" + sql); rs = stmt.executeQuery(sql); while (rs.next()) { System.out.println(rs.getString(1) + "\t" + rs.getString(2)); } } //刪除表 public void deleteTable(String tableName) throws Exception{ String sql = "drop table if exists "+tableName+""; System.out.println("查詢語句:" + sql); stmt.execute(sql); } //查看錶 public void showTables() throws Exception{ String sql = "show tables"; System.out.println("查詢語句:" + sql); rs = stmt.executeQuery(sql); while (rs.next()) { System.out.println(rs.getString(1)); } } //匯入資料(從本地檔案匯入) //檔案userData.txt放到/root下,檔案內容如下 //1 tyf 13388236294 5 //2 zd 12345434565 6 //3 sd 12345434532 5 //4 lsm 12232323232 70 public void loadData(String filePath,String tableName) throws Exception{ String sql = "load data local inpath '" + filePath + "' overwrite into table "+tableName+""; System.out.println("查詢語句:" + sql); stmt.execute(sql); } //查詢資料 public void query(String tableName) throws Exception{ String sql = "select * from "+tableName+""; System.out.println("查詢語句:" + sql); rs = stmt.executeQuery(sql); System.out.println("id" + "\t" + "name" + "\t" + "phone"+"\t" + "age"); while (rs.next()) { System.out.println(rs.getInt("id") + "\t\t" + rs.getString("name") + "\t\t" + rs.getString("phone")+"\t\t" + rs.getInt("age")); } } //清空資料表 public void truncateTable(String tableName)throws Exception{ String sql = "truncate table "+tableName+""; System.out.println("查詢語句:" + sql); stmt.execute(sql); } //count(*) //count(1) //count(column) public void countTable(String tableName,String word) throws Exception{ String sql = "select count('"+word+"') from "+tableName+""; System.out.println("查詢語句:" + sql); rs = stmt.executeQuery(sql); while (rs.next()) { System.out.println(rs.getInt(1) ); } } //多列單次計數 public void wordCount(String tableName,String column)throws Exception{ String sql="select word,count(*) as count from (select explode(split("+column+",'\\t')) as word from tb_user) word group by word order by count"; System.out.println("查詢語句:" + sql); rs = stmt.executeQuery(sql); System.out.println("word" + "\t" + "count" ); while (rs.next()) { System.out.println(rs.getInt("word") + "\t\t" + rs.getString("word") + "\t\t" + rs.getInt("count")); } } public static void main(String [] args) throws Exception{ HiveClient client = new HiveClient(); //檢視資料庫 //client.showDatabases(); //建立資料庫 //client.createDatabase("db_test3"); //刪除資料庫 //client.deleteDatabase("db_test3"); //建立表 //client.createTable("tb_user"); //檢視所有表 //client.showTables(); //查看錶結構 //client.showTable("tb_user"); //刪除表 //client.deleteTable("tb_user"); //匯入資料 //client.loadData("/root/userData.txt","tb_user"); //查詢資料 //client.query("tb_user"); //清空資料表 //client.truncateTable("tb_user"); //記錄計數 //client.countTable("tb_user","*"); //單詞計數 client.wordCount("tb_user","name");//統計一列 } }
單詞統計，結果如圖：
