您好 下面是我为使用 JDBC 连接连接到 Oracle DB 并返回一些值而编写的代码。但是如果我在我的机器上打开 oracle toad，这段代码会建立连接并返回结果。
但是当 oracle toad 关闭并尝试运行这段代码时，它不会连接。
请让我知道如何在不手动打开 oracle toad 的情况下连接到 oracle DB。
package library;
import java.io.IOException;
import java.sql.*;
public class DBAutomationConnection {
public static void main(String args[]) throws ClassNotFoundException, IOException, SQLException {
DBAutomationConnection dbconn = new DBAutomationConnection();
//Connection conn = dbconn.DBConnection1();
dbconn.DBConnection1("select * from employee where empid='test123'","ROLE_NAME");
}
public void DBConnection1(String query, String colName)throws IOException, ClassNotFoundException{
Connection connection = null;
Statement stmt = null;
try {
// Load the JDBC driver
String driverName = "oracle.jdbc.driver.OracleDriver";
Class.forName(driverName);
connection = DriverManager.getConnection("jdbc:oracle:thin:@//testhostname:1528/ServiceName", "XXAAA_U", "Jw9S");
System.out.println("Connection successful: " +connection);
try {
stmt = connection.createStatement();
ResultSet rs = stmt.executeQuery(query);
while (rs.next()) {
//String UserID = rs.getString("USER_ID");
String UserID = rs.getString(colName);
System.out.println(UserID);
}
} catch (SQLException e ) {
System.out.println("Could not execute query.");
//JDBCTutorialUtilities.printSQLException(e);
} finally {
if (stmt != null) { stmt.close(); }
}
} catch (SQLException e) {
System.out.println("Could not connect to the database");
}
}