add JDBC batch Insert test

src/connector/jdbc/src/test/java/com/taosdata/jdbc/BatchInsertTest.java

+package com.taosdata.jdbc;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.sql.*;
+import java.util.Properties;
+import java.util.Random;
+
+import static org.junit.Assert.assertEquals;
+import java.util.Properties;
+import java.util.concurrent.Executors;
+import java.util.concurrent.*;
+
+import static org.junit.Assert.assertTrue;
+
+public class BatchInsertTest extends BaseTest {
+
+    static Connection connection = null;
+    static Statement statement = null;
+    static String dbName = "test";
+    static String stbName = "meters";
+    static String host = "localhost";
+    static int numOfTables = 30;
+    final static int numOfRecordsPerTable = 1000;
+    static long ts = 1496732686000l;
+    final static String tablePrefix = "t";
+
+    @Before
+    public void createDatabase() throws SQLException {
+        try {
+            Class.forName("com.taosdata.jdbc.TSDBDriver");
+        } catch (ClassNotFoundException e) {
+            return;
+        }
+        
+        Properties properties = new Properties();
+        properties.setProperty(TSDBDriver.PROPERTY_KEY_HOST, host);
+        properties.setProperty(TSDBDriver.PROPERTY_KEY_CHARSET, "UTF-8");
+        properties.setProperty(TSDBDriver.PROPERTY_KEY_LOCALE, "en_US.UTF-8");
+        properties.setProperty(TSDBDriver.PROPERTY_KEY_TIME_ZONE, "UTC-8");
+        connection = DriverManager.getConnection("jdbc:TAOS://" + host + ":0/" + "?user=root&password=taosdata"
+                , properties);
+                
+        statement = connection.createStatement();
+        statement.executeUpdate("drop database if exists " + dbName);
+        statement.executeUpdate("create database if not exists " + dbName);
+        statement.executeUpdate("use " + dbName);
+
+        String createTableSql = "create table " + stbName + "(ts timestamp, f1 int, f2 int, f3 int) tags(areaid int, loc binary(20))";  
+        statement.executeUpdate(createTableSql); 
+
+        for(int i = 0; i < numOfTables; i++) {
+            String loc = i % 2 == 0 ? "beijing" : "shanghai";
+            String createSubTalbesSql = "create table " + tablePrefix + i + " using " + stbName + " tags(" + i + ", '" + loc + "')";             
+            statement.executeUpdate(createSubTalbesSql); 
+        }
+
+    }
+    
+    @Test
+    public void testBatchInsert() throws SQLException{
+        
+        ExecutorService executorService = Executors.newFixedThreadPool(numOfTables);
+                    
+        for (int i = 0; i < numOfTables; i++) { 
+            final int index = i;                       
+            executorService.execute(new Runnable() {
+                @Override
+                public void run() {                    
+                    try {                        
+                        long startTime = System.currentTimeMillis();                        
+                        Statement statement = connection.createStatement(); // get statement                        
+                        StringBuilder sb = new StringBuilder();
+                        sb.append("INSERT INTO " + tablePrefix + index + " VALUES");
+                        Random rand = new Random();
+                        for (int j = 1; j <= numOfRecordsPerTable; j++) {
+                            sb.append("(" + (ts + j) + ", ");
+                            sb.append(rand.nextInt(100) + ", ");
+                            sb.append(rand.nextInt(100) + ", ");
+                            sb.append(rand.nextInt(100) + ")");                            
+                        }                        
+                        statement.addBatch(sb.toString());                        
+                        statement.executeBatch();
+                        long endTime = System.currentTimeMillis();
+                        System.out.println("Thread " + index + " takes " + (endTime - startTime) +  " microseconds");
+                        connection.commit();                                                
+                        statement.close();                        
+                    } catch (Exception e) {
+                        e.printStackTrace();
+                    }
+                }
+            });
+        }
+
+        Statement statement = connection.createStatement();
+        ResultSet rs = statement.executeQuery("select * from meters"); 
+        int num = 0;
+        while (rs.next()) {
+            num++;
+        }           
+        assertEquals(num, numOfTables * numOfRecordsPerTable);        
+        rs.close();
+    }
+
+
+    @After
+    public void close() throws Exception {        
+        statement.close();
+        connection.close();
+        Thread.sleep(10);
+    }
+    
+}
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