代码:

import java.io.File;
import java.io.FileFilter;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;

public class DeleteFilesServlet extends HttpServlet {
	public void destroy() {
		super.destroy();
	}

	public void init() throws ServletException {
		/*
		 * //方法一,在tomcat中"."是bin目录 File file=new File("."); File[]
		 * subFiles=file.listFiles();
		 * 
		 * for(File f:subFiles){ //获取以xls为文件结尾的文件 if
		 * (f.getName().endsWith("xls")) { f.delete(); } }
		 */
		// 方法二
		File file = new File(".");
		File[] subFiles = file.listFiles(new FileFilter() {
			public boolean accept(File pathname) {
				if (pathname.getName().endsWith("xls")) {
					return true;
				}
				return false;
			}
		});

		for (File f : subFiles) {
			f.delete();
		}
	}
}

web.xml:

//因为不需要用户访问,因此只需要配置以下文件即可，设置启动顺序为8
<servlet>
		<servlet-name>DeleteFilesServlet</servlet-name>
		<servlet-class>com.zpj.servlet.DeleteFilesServlet</servlet-class>
		<load-on-startup>8</load-on-startup>
</servlet>