Posted on: January 7, 2011 at 12:00 AM
Stream Result example
Stream Result is very important for allowing users to downloading contents. It is a custom result type for sending raw data via InputStream to the HttpServletResponse. It has the following parameters.
contentType- It is the MIME type which is sent on the browser.
inputName- It is the name of the input stream property.
contentLength - It is the Stream length in byte.
bufferSize- It is the size of the buffer to copy from input to output.
allowCaching - Its default value is true. If allowCaching set to false then it will set the Header "Pragma" and Cache-Control to "No-Catche".
contentDisposition - It is used for specifying file name.
An Example of Stream Result is given below
page.jsp
<%@ taglib prefix="s" uri="/struts-tags" %>
<html>
<head>
<title>Chain Result Example</title>
<link href="<s:url value="/css/main.css"/>" rel="stylesheet"
type="text/css"/>
</head>
<body>
<font color="megenta" size="6" face="Comic Sans MS">Stream Result example</font><br clear="all"/><br clear="all"/>
<s:url action="download" id="copy"></s:url>
<strong><font color="green" size="5" face="arier">Click on <s:a href="%{copy}">file</s:a> to Download</font></strong>
</body>
</html>
StreamResultExample.java
package net.roseindia;
import java.io.File;
import java.io.FileInputStream;
import java.io.InputStream;
import com.opensymphony.xwork2.ActionSupport;
public class StreamResultExample extends ActionSupport{
private InputStream fileInputStream;
public InputStream getFileInputStream() {
return fileInputStream;
}
public String execute() throws Exception {
fileInputStream = new FileInputStream(new File("C:\\downloadfile.txt"));
return SUCCESS;
}
}
struts.xml
<?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE struts PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN" "http://struts.apache.org/dtds/struts-2.0.dtd"> <struts> <constant name="struts.enable.DynamicMethodInvocation" value="false" /> <constant name="struts.devMode" value="false" /> <package name="roseindia" extends="struts-default"> <action name="resultStream"> <result name="success">/jsp/page.jsp</result> </action> <action name="download" class="net.roseindia.StreamResultExample"> <result name="success" type="stream"> <param name="contentType">application/octet-stream</param> <param name="inputName">fileInputStream</param> <param name="contentDisposition">attachment;filename="testFile.txt"</param> <param name="bufferSize">1024</param> </result> </action> </package> </struts>
Now Save a text file named downloadfile.txt in the C:\\downloadfile.txt. And then Run The Application Given Below
When you run this application it will display message as shown below:
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