先導入jar包

代碼：

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

public class Firstjdbc {
public static void main(String[] args) throws ClassNotFoundException, SQLException {

//1）註冊加載驅動
Class.forName("com.mysql.jdbc.Driver");
//DriverManager.registerDriver(new com.mysql.jdbc.Driver());
//2）獲得連接
String url = "jdbc:mysql://localhost:3307/mydb" ;//mydb為數據庫的名稱
String user = "root"; //數據庫的登錄名
String password = "123456"; //數據庫的登錄密碼
Connection conn = DriverManager.getConnection(url, user, password);
//3）創建語句對象
Statement st = conn.createStatement();
//4）執行sql獲得結果
String sql = "select * from emp "; //emp為要查詢的表名
ResultSet rs= st.executeQuery(sql);
//5）處理結果
while(rs.next()){
System.out.print(rs.getObject(1)+"\t");
System.out.print(rs.getObject(2)+"\t");
System.out.print(rs.getObject(3)+"\t");
System.out.print(rs.getObject(4)+"\t");
System.out.print(rs.getObject(5)+"\t");
System.out.print(rs.getObject(6)+"\t"); //共輸出要顯示的字段名信息
}
//6）關閉資源
rs.close();
st.close();
conn.close();
}
}

JDBC連接數據庫（查詢）的步驟