JavaWeb 服务启动时，在后台启动加载一个类

两种方法，

一、监听（Listener）

1、创建个监听类,继承ServletContextListener

package tbp.common.xkins;

import javax.servlet.ServletContextEvent;

import net.sf.opentranquera.xkins.core.Skin;

import net.sf.opentranquera.xkins.core.loaders.XkinsLoaderServletContextListener;

import org.apache.commons.lang.StringUtils;

public class XkinsLoaderListenerCustom extends XkinsLoaderServletContextListener {
public void contextInitialized(ServletContextEvent context) {
// Normal XKINS stuffs
super.contextInitialized(context);
String defaultSkin = context.getServletContext().getInitParameter("xkins.defaultSkin");
if (StringUtils.isEmpty(defaultSkin))
defaultSkin = "default";
context.getServletContext().setAttribute(Skin.ATTR_DEFAULT_SKIN_NAME, defaultSkin);
}

}

2、在web.xml中配置,listener类可在web启动时自动加载.

<!-- xkins(皮肤框架)配置 -->
<listener>
<listener-class>tbp.common.xkins.XkinsLoaderListenerCustom</listener-class>
</listener>

二、配置随项目启动而启动的Servlet

1、创建一个类继承HttpServlet,再web.xml配置文件中配置servlet信息

package tbp.component.workflow.service.interf.impl;

import java.net.MalformedURLException;

import java.rmi.RemoteException;

import javax.servlet.ServletConfig;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import tbp.component.workflow.service.interf.RegisterRmi;

public class ExternalInterfaceRmiRegisterServlet extends HttpServlet {
public void init(ServletConfig config) throws ServletException {
    try {
RegisterRmi.startRmi();
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (RemoteException e) {
e.printStackTrace();
}
}

}

2、在web.xml配置一个servlet设置启动顺序优先级高些（即：web服务启动时调用这个类）

<servlet> 
<servlet-name>ExternalInterfaceRmiRegisterServlet </servlet-name> 
<servlet-class>tbp.component.workflow.service.interf.impl.ExternalInterfaceRmiRegisterServlet </servlet-class> 
<!-- 如果需要自动加载，加下面一句 --> 
<load-on-startup>1</load-on-startup> 
</servlet>