spring mvc 在页面中展示图片

页面如下:

<%@page import="java.io.File"%>

<%@ page info="Random Image Show" pageEncoding="UTF-8" contentType="image/jpg"

autoFlush="true" buffer="16kb" session="false" import="java.io.FileInputStream"%>

<%

File file=(File)request.getAttribute("file");

ServletOutputStream sos = response.getOutputStream();

FileInputStream fis = new FileInputStream(file);

byte[] buf = new byte[100]; //缓冲区

int len = 0;

while ((len = fis.read(buf)) != -1) {

sos.write(buf, 0, len);

}

sos.flush();

sos.close();

fis.close();

%>

此时会报 如下异常

Caused by:

java.lang.IllegalStateException: STREAM

at org.eclipse.jetty.server.Response.getWriter(Response.java:697)

at javax.servlet.ServletResponseWrapper.getWriter(ServletResponseWrapper.java:122)

at javax.servlet.ServletResponseWrapper.getWriter(ServletResponseWrapper.java:122)

at com.opensymphony.module.sitemesh.filter.PageResponseWrapper$5.activateDestination(PageResponseWrapper.java:95)

at com.opensymphony.module.sitemesh.filter.RoutablePrintWriter.getDestination(RoutablePrintWriter.java:38)

at com.opensymphony.module.sitemesh.filter.RoutablePrintWriter.write(RoutablePrintWriter.java:144)

at org.apache.jasper.runtime.JspWriterImpl.flushBuffer(JspWriterImpl.java:181)

at org.apache.jasper.runtime.PageContextImpl.release(PageContextImpl.java:237)

at org.apache.jasper.runtime.JspFactoryImpl.internalReleasePageContext(JspFactoryImpl.java:181)

at org.apache.jasper.runtime.JspFactoryImpl.releasePageContext(JspFactoryImpl.java:132)

at org.apache.jsp.WEB_002dINF.views.modules.site.imgView_jsp._jspService(imgView_jsp.java:87)

at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:109)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)

at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:403)

at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:476)

at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:366)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)

at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:652)

at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:445)

at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:137)

at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:574)

at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:227)

at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1044)

at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:372)

at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:189)

at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:978)

at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:135)

at org.eclipse.jetty.server.Dispatcher.forward(Dispatcher.java:293)

at org.eclipse.jetty.server.Dispatcher.forward(Dispatcher.java:120)

at org.springframework.web.servlet.view.InternalResourceView.renderMergedOutputModel(InternalResourceView.java:209)

at org.springframework.web.servlet.view.AbstractView.render(AbstractView.java:267)

at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1217)

at org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:1005)

at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:952)

at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:870)

at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:961)

at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:852)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:707)

at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:837)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)

at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:652)

at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1320)

at com.opensymphony.sitemesh.webapp.SiteMeshFilter.obtainContent(SiteMeshFilter.java:129)

at com.opensymphony.sitemesh.webapp.SiteMeshFilter.doFilter(SiteMeshFilter.java:77)

at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1291)

at com.codahale.metrics.servlet.AbstractInstrumentedFilter.doFilter(AbstractInstrumentedFilter.java:104)

at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1291)

at qnit.common.metric.MetricsFilter.doFilter(MetricsFilter.java:54)

at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1291)

at org.apache.shiro.web.servlet.ProxiedFilterChain.doFilter(ProxiedFilterChain.java:61)

at org.apache.shiro.web.servlet.AdviceFilter.executeChain(AdviceFilter.java:108)

at org.apache.shiro.web.servlet.AdviceFilter.doFilterInternal(AdviceFilter.java:137)

at org.apache.shiro.web.servlet.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:125)

at org.apache.shiro.web.servlet.ProxiedFilterChain.doFilter(ProxiedFilterChain.java:66)

at org.apache.shiro.web.servlet.AbstractShiroFilter.executeChain(AbstractShiroFilter.java:449)

at org.apache.shiro.web.servlet.AbstractShiroFilter$1.call(AbstractShiroFilter.java:365)

at org.apache.shiro.subject.support.SubjectCallable.doCall(SubjectCallable.java:90)

at org.apache.shiro.subject.support.SubjectCallable.call(SubjectCallable.java:83)

at org.apache.shiro.subject.support.DelegatingSubject.execute(DelegatingSubject.java:383)

at org.apache.shiro.web.servlet.AbstractShiroFilter.doFilterInternal(AbstractShiroFilter.java:362)

at org.apache.shiro.web.servlet.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:125)

at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:344)

at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:261)

at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1291)

at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:88)

at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:108)

at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1291)

at org.springframework.orm.hibernate4.support.OpenSessionInViewFilter.doFilterInternal(OpenSessionInViewFilter.java:152)

at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:108)

at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1291)

at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:443)

at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:137)

at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:556)

at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:227)

at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1044)

at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:372)

at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:189)

at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:978)

at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:135)

at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:255)

at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:154)

at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:116)

at org.eclipse.jetty.server.Server.handle(Server.java:367)

at org.eclipse.jetty.server.AbstractHttpConnection.handleRequest(AbstractHttpConnection.java:486)

at org.eclipse.jetty.server.AbstractHttpConnection.headerComplete(AbstractHttpConnection.java:926)

at org.eclipse.jetty.server.AbstractHttpConnection$RequestHandler.headerComplete(AbstractHttpConnection.java:988)

at org.eclipse.jetty.http.HttpParser.parseNext(HttpParser.java:640)

at org.eclipse.jetty.http.HttpParser.parseAvailable(HttpParser.java:235)

at org.eclipse.jetty.server.AsyncHttpConnection.handle(AsyncHttpConnection.java:82)

at org.eclipse.jetty.io.nio.SelectChannelEndPoint.handle(SelectChannelEndPoint.java:628)

at org.eclipse.jetty.io.nio.SelectChannelEndPoint$1.run(SelectChannelEndPoint.java:52)

at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:608)

at org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:543)

at java.lang.Thread.run(Thread.java:745)

查阅资料，

这是web容器生成的servlet代码中有out.write(””)，这个和JSP中调用的response.getOutputStream()产生冲突.

即Servlet规范说明，不能既调用 response.getOutputStream()，又调用response.getWriter()，无论先调用哪一个，在调用第二个时候应会抛出 IllegalStateException，因为在jsp中，out变量是通过response.getWriter得到的，在程序中既用了response.getOutputStream，又用了out变量，故出现以上错误。

JSP页面中的位于<% %>外面的每行和紧临<%%>两边的每段文本被转换成以这些文本作为参数的一条条out.write语句，JSP脚本片断（位于<%%>内的一段java代码）中的java代码被原封不动地搬移进了_jspService方法中的相应位置处，JSP表达式（位于<%=和%>之中的内容）则是被转换成以其中的变量或表达式作为参数的out.print语句。

所以访问jsp,那么一定会调用out.write()方法

修改方案:先调用如下语句

out.clear();

out = pageContext.pushBody();

Return a new BodyContent object, save the current "out" JspWriter,

* and update the value of the "out" attribute in the page scope

* attribute namespace of the PageContext.

public BodyContent pushBody() {

return null; // XXX to implement

}