package com.example.renderer.observer; import java.time.LocalDateTime; import java.time.format.DateTimeFormatter; /** * 记录图形变更日志的观察者实现 */ public class LoggingShapeObserver implements ShapeObserver { private static final DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss"); @Override public void onShapeChanged() { String log = String.format("[%s] 图形发生变化", LocalDateTime.now().format(formatter)); System.out.println(log); } }