Autowired已经灭亡，请使用构造方法注入依赖

Z时代
2024-01-10
分类：综合

这篇文章没有什么好讲的，就是提醒自己不要再使用Autowired引入依赖。

@Autowired

OrderService orderService;

@Autowired

BusinessExamineService businessExamineService;

OrderService orderService;
BusinessExamineService businessExamineService;
public OrderController(OrderService orderService, BusinessExamineService businessExamineService) {
    this.orderService = orderService;
    this.businessExamineService = businessExamineService;
}

1: @Autowired 引入的依赖有可能为null，但方法注入的依赖不会为null

2：方法注入依赖更加高效。

3：开发者不再需要关注bean的构造顺序。不需要关注 @Order。

数字支撑

org.springframework.boot 1.5.6 + Edgware.SR5

org.springframework.boot 2.2.1 +Finchley.SR2

@Autowired 使用量

100+

@Order

30+

备注，这种用法也可以引用相应得依赖。

@Bean
SimpleMessageListenerContainer container(ConnectionFactory connectionFactory) {
    SimpleMessageListenerContainer container = new SimpleMessageListenerContainer();
    container.setConnectionFactory(connectionFactory);
    container.setQueueNames(queueName);
    MessageListenerAdapter listenerAdapter = new MessageListenerAdapter(receiver1, "receiveMessage");
    container.setMessageListener(listenerAdapter);
    return container;
}

而下面这种用法则是不提倡的

@Autowired
ConnectionFactory connectionFactory ;
@Bean
SimpleMessageListenerContainer container() {
    SimpleMessageListenerContainer container = new SimpleMessageListenerContainer();
    container.setConnectionFactory(connectionFactory);
    container.setQueueNames(queueName);
    MessageListenerAdapter listenerAdapter = new MessageListenerAdapter(receiver1, "receiveMessage");
    container.setMessageListener(listenerAdapter);
    return container;
}