Ik gebruik het volgende om afbeeldingen van JPA (Hibernate Backed) weer te geven. Voorbeeld gebruikt de struts2-conventions-plugin, in het resultaattype is de annotatie "stream" alles wat er is voor de weergave:
package com.kenmcwilliams.photogallery.action.gallery;
import com.kenmcwilliams.photogallery.orm.Picture;
import com.kenmcwilliams.photogallery.orm.PictureDetails;
import com.kenmcwilliams.photogallery.service.Gallery;
import com.opensymphony.xwork2.ActionSupport;
import java.io.ByteArrayInputStream;
import java.io.InputStream;
import org.apache.struts2.convention.annotation.Result;
import org.springframework.beans.factory.annotation.Autowired;
@Result(type = "stream", params = {
"contentType", "${contentType}",
"contentLength", "${contentLength}",
"contentDisposition", "${contentDisposition}",
"inputStream", "${inputName}",
"bufferSize", "${bufferSize}",
"allowCaching", "${allowCaching}"
})
public class Stream extends ActionSupport {
@Autowired private Gallery gallery;
private String contentType = "text/plain";
private int contentLength = 0;
private String contentDisposition = "inline";
private InputStream inputStream;
public String inputName = "inputStream";//This should not be required
private Integer bufferSize = 1024;
private String allowCaching = "true";
private Integer id = null;
@Override
public String execute() {
if (id != null){
//gallery.get
PictureDetails details = gallery.getPictureDetails(id);
Picture photo = details.getPictureId();
this.contentType = details.getContentType();
System.out.println("Content Type: " + contentType);
ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(photo.getPicture());
this.contentLength = photo.getPicture().length;
System.out.println("Content Length: " + contentLength);
this.inputStream = byteArrayInputStream;
}else{
return ERROR;
}
return SUCCESS;
}
/**
* @return the contentType
*/
public String getContentType() {
return contentType;
}
/**
* @param contentType the contentType to set
*/
public void setContentType(String contentType) {
this.contentType = contentType;
}
/**
* @return the contentLength
*/
public int getContentLength() {
return contentLength;
}
/**
* @param contentLength the contentLength to set
*/
public void setContentLength(int contentLength) {
this.contentLength = contentLength;
}
/**
* @return the contentDisposition
*/
public String getContentDisposition() {
return contentDisposition;
}
/**
* @param contentDisposition the contentDisposition to set
*/
public void setContentDisposition(String contentDisposition) {
this.contentDisposition = contentDisposition;
}
/**
* @return the bufferSize
*/
public int getBufferSize() {
return bufferSize;
}
/**
* @return the allowCaching
*/
public String getAllowCaching() {
return allowCaching;
}
/**
* @param allowCaching the allowCaching to set
*/
public void setAllowCaching(String allowCaching) {
this.allowCaching = allowCaching;
}
/**
* @return the inputStream
*/
public InputStream getInputStream() {
return inputStream;
}
/**
* @param inputStream the inputStream to set
*/
public void setInputStream(InputStream inputStream) {
this.inputStream = inputStream;
}
/**
* @return the id
*/
public int getId() {
return id;
}
/**
* @param id the id to set
*/
public void setId(int id) {
this.id = id;
}
}
U heeft ook gevraagd hoe u het bovenstaande kunt weergeven, het volgende is een JSP die wordt gebruikt om een galerij met afbeeldingen te tonen (dus de actie zal deze JSP voorzien van afbeeldings-ID's die de bovenstaande actie zal gebruiken om de afbeeldingen uit de database te halen en de titel van de galerij).
Als ik het me goed herinner, toont deze galerij vier foto's breed met zoveel rijen als nodig is om alle foto's te tonen.
<%@taglib prefix="s" uri="/struts-tags"%>
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>JSP Page</title>
</head>
<body>
<h1><s:property value="photoGallery.name"/></h1>
<table>
<s:iterator begin="0" end="pictureDetails.size/4" var="row">
<tr>
<s:subset source="pictureDetails" start="4 * #row" count="4">
<s:iterator>
<s:url forceAddSchemeHostAndPort="true" namespace="/gallery" action="stream" var="streamURL">
<s:param name="id" value="id"/>
</s:url>
<td>
<s:a value="%{#streamURL}"><img width="200px" src="<s:property value="#streamURL"/>"/></s:a>
</td>
</s:iterator>
</s:subset>
</tr>
</s:iterator>
</table>
</body>
</html>
In het bovenstaande is deze regel waarschijnlijk dat dit deel waarschijnlijk is wat u zoekt:
<img width="200px" src="<s:property value="#streamURL"/>"/>