Spring - 将依赖项注入 ServletContextListener

问题描述

我想在 ServletContextListener 中注入一个依赖项.但是，我的方法不起作用.我可以看到 Spring 正在调用我的 setter 方法，但稍后在调用 contextInitialized 时，该属性为 null.

I would like to inject a dependency into a ServletContextListener. However, my approach is not working. I can see that Spring is calling my setter method, but later on when contextInitialized is called, the property is null.

这是我的设置:

ServletContextListener:

public class MyListener implements ServletContextListener{

    private String prop;

    /* (non-Javadoc)
     * @see javax.servlet.ServletContextListener#contextInitialized(javax.servlet.ServletContextEvent)
     */
    @Override
    public void contextInitialized(ServletContextEvent event) {
        System.out.println("Initialising listener...");
        System.out.println(prop);
    }

    @Override
    public void contextDestroyed(ServletContextEvent event) {
    }

    public void setProp(String val) {
        System.out.println("set prop to " + prop);
        prop = val;
    }
}

web.xml:(这是文件中的最后一个监听器)

<listener>
  <listener-class>MyListener</listener-class>
</listener>

applicationContext.xml:

<bean id="listener" class="MyListener">
  <property name="prop" value="HELLO" />
</bean>

输出:

set prop to HELLO
Initialising listener...
null

实现这一目标的正确方法是什么?

What is the correct way to achieve this?

推荐答案

我通过删除侦听器 bean 并为我的属性创建一个新 bean 解决了这个问题.然后我在我的监听器中使用以下内容来获取属性 bean:

I resolved this by removing the listener bean and creating a new bean for my properties. I then used the following in my listener, to get the properties bean:

@Override
public void contextInitialized(ServletContextEvent event) {

    final WebApplicationContext springContext = WebApplicationContextUtils.getWebApplicationContext(event.getServletContext());
    final Properties props = (Properties)springContext.getBean("myProps");
}

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