在线等 !求助,在做servlet测试的时候发生错误,抛出异常,内详,谢谢

Java code

import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;

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

import com.sun.xml.internal.fastinfoset.sax.Properties;

//读取资源文件
public class ServletDemo11 extends HttpServlet {

    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        
        InputStream in = this.getServletContext().getResourceAsStream(
                "/WEB-INF/classes/db.properties");
        Properties props = new Properties();
        props.load(in);

        String url = props.getProperty("url");
        String username = props.getProperty("username");
        String password = props.getProperty("password");
        
        System.out.println(url);
        System.out.println(username);
        System.out.println(password);
    }

    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        doGet(request, response);
    }

抛出了
2012-7-5 16:28:24 org.apache.catalina.core.StandardWrapperValve invoke
严重: Servlet.service() for servlet [ServletDemo11] in context with path [/day5] threw exception [Servlet execution threw an exception] with root cause
java.lang.Error: Unresolved compilation problems: 
The method load(InputStream) is undefined for the type Properties
The method getProperty(String) is undefined for the type Properties
The method getProperty(String) is undefined for the type Properties
The method getProperty(String) is undefined for the type Properties

at cn.itcast.ServletDemo11.doGet(ServletDemo11.java:23)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:224)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:169)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:168)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:928)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:987)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:539)
at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoint.java:1815)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run