基本概念
构建，也叫构造器，用来帮助创建对象的方法，准确的说，构造方法的作用是初始化对象
定义
格式：修饰符 构造方法名（参数列表）{方法体}
## 要求：方法名必须与类名一样
没有返回值（可以写return）
没有返回值类型（不能写void）
注意事项
如果没有提供任何构造方法，系统会给出默认无参构造；构造方法可以重载
java-构造方法
When nothing seems to help, I go look at a stonecutter hammering away at his rock, perhaps a hundred times without as much as a crack showing in it. Yet at the hundred and first blow it will split in two, and I know it was not that blow that did it, but all that had gone before. -- Jacob Riis