三种ApplicationContext依赖注入的方式
1、注解
@Component
public class User {
@Autowired
private ApplicationContext applicationContext;
public void show() {
System.out.println("user:"+applicationContext.getClass());
}
}
2、实现ApplicationContextAware接口
@Component
public class Book implements ApplicationContextAware {
private ApplicationContext applicationcontext;
public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
this.applicationcontext=applicationContext;
}
public void show() {
System.out.println("book:"+applicationcontext.getClass());
}
}
3、构造方法直接构造（局限性 1⃣️构造函数只能有一个，如果有多个必须要有无参构造此时spring 就会调用无参，不会调用 applicationcontext
2⃣️构造函数的参数，必须要在Spring 容器中有 ）
@Component
public class Bank {
private ApplicationContext applicationContext;
public Bank(ApplicationContext applicationContext) {
this.applicationContext=applicationContext;
}
public void show() {
System.out.println("Bank:"+applicationContext.getClass());
}
}