spring mvc 图片流输出到页面

spring mvc不像struts2：

<action name="TwoDimensionalCodeAction" class="com.wsg.action.TwoDimensionalCodeAction">
	<result type="stream">
               <param name="inputName">inputStream</param>  
	</result>
	<result name="testForm">/form_success.jsp</result>
</action>

直接设置结果既可实现跳转，显示页面。

在spring mvc的action中需要设置response,具体如下：

TwoDimensionalCode tdc =new TwoDimensionalCode();   
response.setContentType("image/jpeg");
ServletOutputStream op = response.getOutputStream();
tdc.getOutputStream().writeTo(op);
op.close();
response.flushBuffer();
System.out.println("二维码的值："+tdc.getContext());

 tdc.getOutputStream()为二维码的二进制流。

这样选择相应的跳转，return null即可！

这样在把二进制流发送到页面时，response的流会出现一个问题:

threw exception [java.lang.IllegalStateException: getOutputStream() has already been called for this response] with root cause
java.lang.IllegalStateException: getOutputStream() has already been called for this response

 

这个时候页面加上以下代码即可解决

 	<%
        out.clear();
        out=pageContext.pushBody();
  	 %>