Spring - 将依赖项注入到ServletContextListener中

问题描述

我想将一个依赖项注入到一个 ServletContextListener 中。但是，我的做法不行。我可以看到Spring正在调用setter方法，但是后来当调用 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听众）

<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

正确的方法是什么？

推荐答案

我通过删除监听器bean并为我的属性创建一个新bean。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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