hive-查询元数据

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

 public  
 class  
 HiveJdbcClient { 
 
 private  
 static  
 String driverName =  
 "org.apache.hive.jdbc.HiveDriver" 
 ; 

 /** 
 
 * @param args 
 
 * @throws SQLException 
 
 */ 
 
 public  
 static  
 void  
 main(String[] args)  
 throws  
 SQLException { 
 
 try  
 { 
 
 Class.forName(driverName); 
 
 }  
 catch  
 (ClassNotFoundException e) { 
 
 // TODO Auto-generated catch block 
 
 e.printStackTrace(); 
 
 System.exit( 
 1 
 ); 
 
 } 
 
 //replace "hive" here with the name of the user the queries should run as 
 
 Connection con = DriverManager.getConnection( 
 "jdbc:hive2://localhost:10000/default" 
 ,  
 "hive" 
 ,  
 "" 
 ); 
 
 Statement stmt = con.createStatement(); 
 
 String tableName =  
 "testHiveDriverTable" 
 ; 
 
 stmt.execute( 
 "drop table if exists "  
 + tableName); 
 
 stmt.execute( 
 "create table "  
 + tableName +  
 " (key int, value string)" 
 ); 
 
 // show tables 
 
 String sql =  
 "show tables '"  
 + tableName +  
 "'" 
 ; 
 
 System.out.println( 
 "Running: "  
 + sql); 
 
 ResultSet res = stmt.executeQuery(sql); 
 
 if  
 (res.next()) { 
 
 System.out.println(res.getString( 
 1 
 )); 
 
 } 
 
 // describe table 
 
 sql =  
 "describe "  
 + tableName; 
 
 System.out.println( 
 "Running: "  
 + sql); 
 
 res = stmt.executeQuery(sql); 
 
 while  
 (res.next()) { 
 
 System.out.println(res.getString( 
 1 
 ) +  
 "t"  
 + res.getString( 
 2 
 )); 
 
 } 

 // load data into table 
 
 // NOTE: filepath has to be local to the hive server 
 
 // NOTE: /tmp/a.txt is a ctrl-A separated file with two fields per line 
 
 String filepath =  
 "/tmp/a.txt" 
 ; 
 
 sql =  
 "load data local inpath '"  
 + filepath +  
 "' into table "  
 + tableName; 
 
 System.out.println( 
 "Running: "  
 + sql); 
 
 stmt.execute(sql); 

 // select * query 
 
 sql =  
 "select * from "  
 + tableName; 
 
 System.out.println( 
 "Running: "  
 + sql); 
 
 res = stmt.executeQuery(sql); 
 
 while  
 (res.next()) { 
 
 System.out.println(String.valueOf(res.getInt( 
 1 
 )) +  
 "t"  
 + res.getString( 
 2 
 )); 
 
 } 

 // regular hive query 
 
 sql =  
 "select count(1) from "  
 + tableName; 
 
 System.out.println( 
 "Running: "  
 + sql); 
 
 res = stmt.executeQuery(sql); 
 
 while  
 (res.next()) { 
 
 System.out.println(res.getString( 
 1 
 )); 
 
 } 
 
 } 
 
 } 
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