验证码框架使用有问题

xiaomaha 2008-03-20 08:16:32

我找了一个验证码，使用的时候要出异常！但页面能正常显示



<%@ page contentType="image/jpeg" 



import="java.awt.*,java.awt.image.*,java.util.*,javax.imageio.*" pageEncoding="utf-8" %>

<%!

Color getRandColor(int fc,int bc){//给定范围获得随机颜色

        Random random = new Random();

        if(fc>255) fc=255;

        if(bc>255) bc=255;

        int r=fc+random.nextInt(bc-fc);

        int g=fc+random.nextInt(bc-fc);

        int b=fc+random.nextInt(bc-fc);

        return new Color(r,g,b);

        }

%>

<%

//设置页面不缓存

response.setHeader("Pragma","No-cache");

response.setHeader("Cache-Control","no-cache");

response.setDateHeader("Expires", 0);



// 在内存中创建图象

int width=60, height=20;

BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);



// 获取图形上下文

Graphics g = image.getGraphics();



//生成随机类

Random random = new Random();



// 设定背景色

g.setColor(getRandColor(200,250));

g.fillRect(0, 0, width, height);



//设定字体

g.setFont(new Font("Times New Roman",Font.PLAIN,18));



//画边框

//g.setColor(new Color());

//g.drawRect(0,0,width-1,height-1);





// 随机产生155条干扰线，使图象中的认证码不易被其它程序探测到

g.setColor(getRandColor(160,200));

for (int i=0;i<155;i++)

{

 int x = random.nextInt(width);

 int y = random.nextInt(height);

        int xl = random.nextInt(12);

        int yl = random.nextInt(12);

 g.drawLine(x,y,x+xl,y+yl);

}



// 取随机产生的认证码(4位数字)

String sRand="";

for (int i=0;i<4;i++){

    String rand=String.valueOf(random.nextInt(10));

    sRand+=rand;

    // 将认证码显示到图象中

    g.setColor(new Color(20+random.nextInt(110),20+random.nextInt(110),20+random.nextInt



(110)));//调用函数出来的颜色相同，可能是因为种子太接近，所以只能直接生成

    g.drawString(rand,13*i+6,16);

}



// 将认证码存入SESSION

session.setAttribute("rand",sRand);





// 图象生效

g.dispose();



// 输出图象到页面

ImageIO.write(image, "JPEG", response.getOutputStream());





%>





<%@ page language="java" pageEncoding="utf-8"%>



<%@ taglib uri="http://struts.apache.org/tags-bean" prefix="bean" %>

<%@ taglib uri="http://struts.apache.org/tags-html" prefix="html" %>

<%@ taglib uri="http://struts.apache.org/tags-logic" prefix="logic" %>

<%@ taglib uri="http://struts.apache.org/tags-tiles" prefix="tiles" %>





<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">

<html:html lang="true">

  <head>

    <html:base />

    

    <title>logic.jsp</title>



	<!--

	<link rel="stylesheet" type="text/css" href="styles.css">

	-->



  </head>

  

  <body>

<html:errors/>

    <html:form action="logic.do" method="post">

    	用户<html:text property="name"></html:text>

    	<br>

    	密码<html:password property="password"></html:password>

    	<br>

    	性别<html:radio property="sex" value="男">男</html:radio>

    	<html:radio property="sex" value="女">女</html:radio>

    	<br>

    	年龄<html:select property="age">

    		<html:option value="成年">18-30</html:option>

    		<html:option value="未成年">0-17</html:option>

    	</html:select>

    	<br>

    	<html:text property="yz"></html:text><html:img src="xxx.jsp"/>

    	<html:submit value="提交"></html:submit>

    </html:form>

  </body>

</html:html>

错误信息：
20:15:36,093 ERROR [jsp]:253 - 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:607)
at org.apache.catalina.connector.ResponseFacade.getWriter(ResponseFacade.java:196)
at org.apache.jasper.runtime.JspWriterImpl.initOut(JspWriterImpl.java:125)
at org.apache.jasper.runtime.JspWriterImpl.flushBuffer(JspWriterImpl.java:118)
at org.apache.jasper.runtime.PageContextImpl.release(PageContextImpl.java:179)
at org.apache.jasper.runtime.JspFactoryImpl.internalReleasePageContext(JspFactoryImpl.java:116)
at org.apache.jasper.runtime.JspFactoryImpl.releasePageContext(JspFactoryImpl.java:76)
at org.apache.jsp.xxx_jsp._jspService(xxx_jsp.java:133)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:98)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:331)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:329)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:265)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:269)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
at com.filter.EncodingFilter.doFilter(EncodingFilter.java:24)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:215)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:174)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:108)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:151)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:874)
at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:665)
at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:528)
at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:81)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:689)
at java.lang.Thread.run(Unknown Source)

...全文

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xiaomaha 2008-03-20

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[Quote=引用 1 楼 xyz20003 的回复:]
老问题了，jsp中的getWriter和getOutputStream冲突
一个方法是去掉所有的 <%%>外的回车和空格。

另一个方法
在使用完输出流以后调用以下两行代码：

out.clear();
out = pageContext.pushBody();
[/Quote]

感谢`·