public static void main(String[] args) throws Exception {//1.导入驱动jar包//2.注册驱动Class.forName("com.mysql.cj.jdbc.Driver");//3.获取数据库连接对象Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/ydy?serverTimezone=GMT%2B8", "root", "123456");//4.定义sql语句String sql="update user set age=30 where id =4";//5.获取执行sql对象Statement stmt=conn.createStatement();//6.执行sqlint age=stmt.executeUpdate(sql);//7.处理结果System.out.println(age);//8.释放资源stmt.close();conn.close();}

运行结果，返回的是受影响的行数

resultset操作

public class JdbcDemo4 {public static void main(String[] args) {Connection conn=null;Statement stmt=null;ResultSet rs=null;try {Class.forName("com.mysql.cj.jdbc.Driver");conn= DriverManager.getConnection("jdbc:mysql://localhost:3306/ydy?serverTimezone=GMT%2B8", "root", "123456");String sql="select * from user";stmt=conn.createStatement();rs=stmt.executeQuery(sql);while (rs.next()){int id =rs.getInt(1);String name=rs.getString("name");String address=rs.getString("address");System.out.println(id+"----"+name+"-----"+address);}} catch (ClassNotFoundException e) {e.printStackTrace();} catch (SQLException e) {e.printStackTrace();}finally {if(rs!=null){try{rs.close();}catch(SQLException e){e.printStackTrace();}}if(stmt!=null){try{stmt.close();}catch(SQLException e){e.printStackTrace();}}if(conn!=null){try{conn.close();}catch(SQLException e){e.printStackTrace();}}}}
}

运行结果如下：