java操作数据库 jdbc

Class.forName("com.mysql.jdbc.Driver");
Connection connection = DriverManager.getConnection("jdbc:mysql://localhost:3306/scott", "root", "123456");
Statement statement = connection.createStatement();
ResultSet resultSet = statement.executeQuery("select * from emp");
while (resultSet.next()){
    int id = resultSet.getInt("id");
}
int i = statement.executeUpdate("update emp set sal=100 whre id =1 ");

conn = DriverManager.getConnection(
          "jdbc:mysql://localhost:3306/scott", "root", "123456");
//3.创建查询通道
//创建prepareStatement的时候就会提供sql
PreparedStatement ps = conn.prepareStatement("select * from dept "
                                             + "where "
                                             + " dname like concat('%',?,'%')");
ps.setString(1, "ACCOUNTING");
//4.获取结果集
ResultSet rs = ps.executeQuery();
while(rs.next()) {
  System.out.println(rs.getObject(1)+","+rs.getObject(2)+","+rs.getObject(3));
}