Question

r_image.jsp

    <jsp:include page="precheck.jsp"></jsp:include>
<%@page import="java.io.InputStream"%>
<%@page import="java.io.FileInputStream"%>
<%@page import="java.io.File"%>
<%@page import="java.io.*"%>
<%@page import="java.sql.DriverManager"%>
<%@page import="java.sql.ResultSet"%>
<%@page import="java.sql.PreparedStatement"%>
<%@page import="java.sql.Connection"%>
<%@page language="java" trimDirectiveWhitespaces="true"%>
<%@page import="java.sql.*"%>
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>

<%
Connection conn;
PreparedStatement pstm;
ResultSet rs;
String url = "jdbc:mysql://localhost:3306/inventory";//Here the "test" is the Database name
try{
String sid=(String)session.getAttribute("session-sid");
    Class.forName("com.mysql.jdbc.Driver");
    conn = DriverManager.getConnection(url, "root", "");
    String q = "select * from tblstore where sid='"+sid+"'";
    PreparedStatement ps = conn.prepareStatement(q);
    ResultSet rs1 = ps.executeQuery();
    int i = 0;

           if(rs1.next()){
              String imgLen = rs1.getString(1);
           int len = imgLen.length();
           System.out.println("Length:"+len);
           byte [] rb = new byte[len];
           InputStream readImg = rs1.getBinaryStream(1);
           int index=readImg.read(rb, 0, len);
           response.setContentType("image/jpg");
           OutputStream obj=response.getOutputStream();
           obj.write(rb,0,len);
           obj.flush();
           obj.close();
           return;
           }

}
catch(Exception ex){
    System.out.println(ex.getMessage());
}
%>

</body>
</html>

profile.html

<img src="r_image.jsp" />

我想通过使用上面的HTML标签来检索所需的图像，它就像一个魅力，但在后台展示了一个例外，展示了原因：的异常

    SEVERE: Servlet.service() for servlet [jsp] in context with path [/inv] 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
    at org.apache.catalina.connector.Response.getWriter(Response.java:627)
    at org.apache.catalina.connector.ResponseFacade.getWriter(ResponseFacade.java:215)
    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:190)
    at org.apache.jasper.runtime.JspFactoryImpl.internalReleasePageContext(JspFactoryImpl.java:123)
    at org.apache.jasper.runtime.JspFactoryImpl.releasePageContext(JspFactoryImpl.java:80)
    at org.apache.jsp.r_005fimage_jsp._jspService(r_005fimage_jsp.java:124)
    at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
    at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:433)
    at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:389)
    at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:333)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:304)
    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:185)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:151)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:929)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:405)
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:269)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:515)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:302)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at java.lang.Thread.run(Thread.java:722)

为什么在图像仍在检索时出现此异常且效果很好！

Answer 1

您应该使用Servlet在响应中发送二进制数据，而不是JSP页面。 JSP页面发送文本输出，并将调用getWriter方法以便从JSP页面发送缓冲输出。

另见java.lang.IllegalStateException: getOutputStream() has already been called for this response

在检索图像时，已经为此响应调用了getOutputStream（）

1 个答案: