重写init(ServletConfig)方法，调用super.init(ServletConfig)

public class InitBeanFactoryServlet extends HttpServlet {
	
	public static final String INIT_FACTORY_NAME = "_my_bean_factory";
	
	@Override
	public void init(ServletConfig config) throws ServletException {
		super.init(config);
		BeanFactory factory = null;
		String configLocation = config.getInitParameter("configLocation");
		if(configLocation == null){
			factory = new PropertiesBeanFactory();
		}else{
			factory = new PropertiesBeanFactory(configLocation);
		}
		System.out.println("初始化BeanFactory......");
		getServletContext().setAttribute(INIT_FACTORY_NAME, factory);
		
		//初始化BeanUtils的转换器
		ConvertUtils.register(new ChannelsSetConverter(), Set.class);
	}

}

 

当重写init(ServletConfig)方法的时候，记得调用super.init(ServletConfig)
调用super.init(ServletConfig)的目的，主要是由于在父类（GenericServlet）中
有一个ServletConfig实例变量，super.init(ServletConfig)就是给这个实例变量复制。

这样，再后续的getServletContext()操作，才可以拿到ServletContext对象:
GenericServlet的部分源代码如下所示：

 

public abstract class GenericServlet 
    implements Servlet, ServletConfig, java.io.Serializable
{

    private transient ServletConfig config;
    
    public void init(ServletConfig config) throws ServletException {
		this.config = config;
		this.init();
    }
    public void init() throws ServletException {
    }    
    public ServletConfig getServletConfig() {
		return config;
    }
    public ServletContext getServletContext() {
		return getServletConfig().getServletContext();
    }