用法
依赖关系
- JDK >= 1.8
- Maven >= 3.0
如何仅打包jdbc项目
在根目录中:
mvn clean package -pl jdbc -am -Dmaven.test.skip=true
如何在本地Maven存储库中安装
在根目录中:
mvn clean install -pl jdbc -am -Dmaven.test.skip=true
结合使用IoTDB JDBC和Maven
<dependencies>
<dependency>
<groupId>org.apache.iotdb</groupId>
<artifactId>iotdb-jdbc</artifactId>
<version>0.8.2</version>
</dependency>
</dependencies>
例子
本章提供了有关如何打开数据库连接,执行SQL查询以及显示结果的示例。
要求您包含包含数据库编程所需的JDBC类的软件包。
import java.sql.*;
import org.apache.iotdb.jdbc.IoTDBSQLException;
/**
* Before executing a SQL statement with a Statement object, you need to create a Statement object using the createStatement() method of the Connection object.
* After creating a Statement object, you can use its execute() method to execute a SQL statement
* Finally, remember to close the 'statement' and 'connection' objects by using their close() method
* For statements with query results, we can use the getResultSet() method of the Statement object to get the result set.
*/
public static void main(String[] args) throws SQLException {
Connection connection = getConnection();
if (connection == null) {
System.out.println("get connection defeat");
return;
}
Statement statement = connection.createStatement();
//Create storage group
try {
statement.execute("SET STORAGE GROUP TO root.demo");
}catch (IoTDBSQLException e){
System.out.println(e.getMessage());
}
//Show storage group
statement.execute("SHOW STORAGE GROUP");
outputResult(statement.getResultSet());
//Create time series
//Different data type has different encoding methods. Here use INT32 as an example
try {
statement.execute("CREATE TIMESERIES root.demo.s0 WITH DATATYPE=INT32,ENCODING=RLE;");
}catch (IoTDBSQLException e){
System.out.println(e.getMessage());
}
//Show time series
statement.execute("SHOW TIMESERIES root.demo");
outputResult(statement.getResultSet());
//Execute insert statements in batch
statement.addBatch("insert into root.demo(timestamp,s0) values(1,1);");
statement.addBatch("insert into root.demo(timestamp,s0) values(1,1);");
statement.addBatch("insert into root.demo(timestamp,s0) values(2,15);");
statement.addBatch("insert into root.demo(timestamp,s0) values(2,17);");
statement.addBatch("insert into root.demo(timestamp,s0) values(4,12);");
statement.executeBatch();
statement.clearBatch();
//Full query statement
String sql = "select * from root.demo";
ResultSet resultSet = statement.executeQuery(sql);
System.out.println("sql: " + sql);
outputResult(resultSet);
//Exact query statement
sql = "select s0 from root.demo where time = 4;";
resultSet= statement.executeQuery(sql);
System.out.println("sql: " + sql);
outputResult(resultSet);
//Time range query
sql = "select s0 from root.demo where time >= 2 and time < 5;";
resultSet = statement.executeQuery(sql);
System.out.println("sql: " + sql);
outputResult(resultSet);
//Aggregate query
sql = "select count(s0) from root.demo;";
resultSet = statement.executeQuery(sql);
System.out.println("sql: " + sql);
outputResult(resultSet);
//Delete time series
statement.execute("delete timeseries root.demo.s0");
//close connection
statement.close();
connection.close();
}
public static Connection getConnection() {
// JDBC driver name and database URL
String driver = "org.apache.iotdb.jdbc.IoTDBDriver";
String url = "jdbc:iotdb://127.0.0.1:6667/";
// Database credentials
String username = "root";
String password = "root";
Connection connection = null;
try {
Class.forName(driver);
connection = DriverManager.getConnection(url, username, password);
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
}
return connection;
}
/**
* This is an example of outputting the results in the ResultSet
*/
private static void outputResult(ResultSet resultSet) throws SQLException {
if (resultSet != null) {
System.out.println("--------------------------");
final ResultSetMetaData metaData = resultSet.getMetaData();
final int columnCount = metaData.getColumnCount();
for (int i = 0; i < columnCount; i++) {
System.out.print(metaData.getColumnLabel(i + 1) + " ");
}
System.out.println();
while (resultSet.next()) {
for (int i = 1; ; i++) {
System.out.print(resultSet.getString(i));
if (i < columnCount) {
System.out.print(", ");
} else {
System.out.println();
break;
}
}
}
System.out.println("--------------------------\n");
}
}