关于spring的空指针错误

关于spring的空指针异常
这是我的applicationContext.xml的配置；
<bean id="themeDao" ref="themeDao"></property>
</bean>
<bean id="themeAction" ref="themeService"></property>
</bean>

我的访问的ThemeAction大致代码如下：

public class ThemeAction extends ActionSupport {
private ThemeService themeService;

public ThemeService getThemeService() {
return themeService;
}

public void setThemeService(ThemeService themeService) {
this.themeService = themeService;
}



public String find() {
System.out.println(getThemeService() + "000000000000000");
//themes = themeService.findAll();
return NONE;
}
}


结果一访问这个action，发现themeService为null，它不是应该被spring自动注入的吗？