Question

我正在尝试使用实例变量初始化bean。所以我有基类，它包含给定queueName和messageListener创建队列的信息。

bean没有初始化。有人可以查看我的代码和帮助。我的目标是创建其他类可以用来减少代码重复性的类。这就是我使用实例变量来创建bean的原因。

//class Application

package com.ats.myntra;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class Application {

    public static void main(String[] args) throws Exception {
        SpringApplication.run(Application.class);
    }
}








//class RabbitMqQueue

import javax.annotation.PostConstruct;

import org.springframework.amqp.core.MessageListener;
import org.springframework.amqp.core.Queue;
import org.springframework.amqp.rabbit.connection.ConnectionFactory;
import org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer;
import org.springframework.amqp.rabbit.listener.adapter.MessageListenerAdapter;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class RabbitMqQueue {
    private String queue;
    private MessageListener messageListener;

    public RabbitMqQueue(String queue, MessageListener messageListener){
        this.queue = queue;
        this.messageListener = messageListener;
    }

    @Bean
    MessageListenerAdapter listenerAdapter() {
        return new MessageListenerAdapter(messageListener, "onMessage");
    }

    @PostConstruct
    SimpleMessageListenerContainer container(ConnectionFactory connectionFactory) {
        SimpleMessageListenerContainer container = new SimpleMessageListenerContainer();
        container.setConnectionFactory(connectionFactory);
        container.setQueueNames(queue);
        container.setMessageListener(messageListener);
        return container;
    }

    @Bean
    Queue queue() {
        return new Queue(queue, false);
    }

}





//class q1
package Configuration;


import org.springframework.amqp.core.Message;
import org.springframework.amqp.core.MessageListener;
import org.springframework.stereotype.Component;

@Component
public class q1 implements MessageListener{

    q1 q = new q1();
    String queue = "abcd";


    RabbitMqQueue rabbitMqQueue = new RabbitMqQueue(queue,q);


    static void print(){
        System.out.println("why");
    }

    //rabbitMqQueue = 
    @Override
    public void onMessage(Message message) {
        // TODO Auto-generated method stub

    }   
}

Answer 1

问题在于您的配置类。不要对这些值使用构造函数注入，而是直接在字段上注入。我修改了您的示例，假设您的配置文件中有一个名为“queue.name”的属性，但您可以将其更改为您正在使用的任何属性。

@Configuration
public class RabbitMqQueue {

    @Value("${queue.name}")
    private String queue;

    @Autowired
    private MessageListener messageListener;

    @Bean
    MessageListenerAdapter listenerAdapter() {
        return new MessageListenerAdapter(messageListener, "onMessage");
    }

    @PostConstruct
    SimpleMessageListenerContainer container(ConnectionFactory connectionFactory) {
        SimpleMessageListenerContainer container = new SimpleMessageListenerContainer();
        container.setConnectionFactory(connectionFactory);
        container.setQueueNames(queue);
        container.setMessageListener(messageListener);
        return container;
    }

    @Bean
    Queue queue() {
        return new Queue(queue, false);
    }

}

或者，您实际上只需将值注入bean工厂方法，如下所示：

//snip
    @Bean
    @Autowired
    MessageListenerAdapter listenerAdapter(private MessageListener messageListener) {
        return new MessageListenerAdapter(messageListener, "onMessage");
    }
//snip
    @Bean
    Queue queue(@Value("${queue.name}" String queueName){

        return new Queue(queue, false);
    }       
//snip

希望有所帮助：）

春天的靴子。使用实例变量初始化Bean

1 个答案: