我的配制没什么问题~运行后TOMACT报错:
2007-5-20 2:55:53 org.apache.catalina.core.StandardWrapperValve invoke
严重: Servlet.service() for servlet jsp threw exception
java.lang.IllegalStateException: getOutputStream() has already been called for this response
at org.apache.catalina.connector.Response.getWriter(Response.java:599)
at org.apache.catalina.connector.ResponseFacade.getWriter(ResponseFacade.java:195)
at org.apache.jasper.runtime.JspWriterImpl.initOut(JspWriterImpl.java:124)
at org.apache.jasper.runtime.JspWriterImpl.flushBuffer(JspWriterImpl.java:117)
at org.apache.jasper.runtime.PageContextImpl.release(PageContextImpl.java:182)
at org.apache.jasper.runtime.JspFactoryImpl.internalReleasePageContext(JspFactoryImpl.java:115)
at org.apache.jasper.runtime.JspFactoryImpl.releasePageContext(JspFactoryImpl.java:75)
at org.apache.jsp.Random_jsp._jspService(Random_jsp.java:135)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:97)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:334)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:314)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:264)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:252)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:178)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:126)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:105)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:107)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:148)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:869)
at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:664)
at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:527)
at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:80)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:684)
at java.lang.Thread.run(Thread.java:595)JSP如下~!<%@ page contentType="image/jpeg" %>
<%@ page import="java.awt.*,java.awt.image.*" %>
<%@ page import="java.util.*,javax.imageio.*" %><%!  
//产生随机颜色函数getRandColor
     Color getRandColor(int fc,int bc){
        Random r = new Random();
        if(fc>255) fc=255;
        if(bc>255) bc=255;
        int red=fc+r.nextInt(bc-fc);    //红
        int green=fc+r.nextInt(bc-fc);  //绿
        int blue=fc+r.nextInt(bc-fc);   //蓝
        return new Color(red,green,blue);
     }
%><%
//设置页面不缓存
    response.setHeader("Pragma","No-cache");
    response.setHeader("Cache-Control","no-cache");
    response.setDateHeader("Expires", 0);
    
//创建随机类
    Random r = new Random();// 在内存中创建图像,宽度为width,高度为height
    int width=60, height=20;
    BufferedImage pic = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);// 获取图形上下文环境
    Graphics gc = pic.getGraphics();// 设定背景色并进行填充
    gc.setColor(getRandColor(200,250));
    gc.fillRect(0, 0, width, height);//设定图形上下文环境字体
    gc.setFont(new Font("Times New Roman",Font.PLAIN,18));// 随机产生200条干扰直线,使图像中的认证码不易被其他分析程序探测到
    gc.setColor(getRandColor(160,200));
    for (int i=0;i<200;i++){
        int x1 = r.nextInt(width);
        int y1 = r.nextInt(height);
        int x2 = r.nextInt(15);
        int y2 = r.nextInt(15);
        gc.drawLine(x1,y1,x1+x2,y1+y2);
    }
//随机产生100个干扰点,使图像中的验证码不易被其他分析程序探测到
gc.setColor(getRandColor(120,240));
for (int i=0;i<100;i++) 
{
int x = r.nextInt(width); 
int y = r.nextInt(height); 
gc.drawOval(x,y,0,0); 
} // 随机产生4位数字的验证码
    String RS="";
    String rn="";
    for(int i=0;i<4;i++){
        //产生10以内随机数字rn
        rn=String.valueOf(r.nextInt(10));
        RS+=rn;
        //将认证码用drawString函数显示到图像里
        gc.setColor(new Color(20+r.nextInt(110),20+r.nextInt(110),20+r.nextInt(110)));
        gc.drawString(rn,13*i+6,16);
    }// 释放图形上下文环境
    gc.dispose();// 将认证码RS存入SESSION中共享
    session.setAttribute("random",RS);// 输出生成后的验证码图像到页面
    ImageIO.write(pic, "JPEG", response.getOutputStream());
  
%>