如何使用JDBC获取表的列的数据类型？
您可以使用ResultSetMetaData类的getColumnType()方法获取表的列的数据类型。
//检索ResultSetMetaData对象 ResultSetMetaData rsmd = rs.getMetaData(); //获取列类型 String column_name = rsmd.getColumnTypeName(2);
假设我们在数据库中有一个名为employee_data的表，其描述如下所示：
+----------+--------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +----------+--------------+------+-----+---------+-------+ | id | int(11) | YES | | NULL | | | Name | varchar(255) | YES | | NULL | | | Dob | date | YES | | NULL | | | Location | varchar(255) | YES | | NULL | | +----------+--------------+------+-----+---------+-------+
接下来的JDBC程序建立与数据库的连接，检索employee_data表的ResultSetMetaData对象，并打印第三列的数据类型。
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.Statement;
public class TypeOfColumn {
public static void main(String args[])throws Exception {
//注册驱动程序
DriverManager.registerDriver(new com.mysql.jdbc.Driver());
//获得连接
String mysqlUrl = "jdbc:mysql://localhost/mydatabase";
Connection con = DriverManager.getConnection(mysqlUrl, "root", "password");
System.out.println("Connection established......");
//创建一个Statement对象
Statement stmt = con.createStatement();
ResultSet rs = stmt.executeQuery("select * from employee_data");
//检索ResultSetMetaData对象
ResultSetMetaData rsmd = rs.getMetaData();
//获取列类型
String column_name = rsmd.getColumnTypeName(3);
System.out.println("Data type of the column with the specified index is: "+column_name);
}
}输出结果
Connection established...... Data type of the column with the specified index is: DATE