imageservice.java

Enjoy Web Dev With Tapestry 一书的源代码

package com.ttdev.album;

import java.io.*;
import java.util.*;

import javax.servlet.http.*;

import org.apache.hivemind.*;
import org.apache.tapestry.*;
import org.apache.tapestry.engine.*;
import org.apache.tapestry.services.*;

public class ImageService implements IEngineService {
	private HttpServletResponse response;
	private LinkFactory linkFactory;
	private Infrastructure infrastructure;

	public void setInfrastructure(Infrastructure infrastructure) {
		this.infrastructure = infrastructure;
	}

	public void setResponse(HttpServletResponse response) {
		this.response = response;
	}
	public void setLinkFactory(LinkFactory linkFactory) {
		this.linkFactory = linkFactory;
	}
	public String getName() {
		return "image";
	}
	public void service(IRequestCycle cycle) throws IOException {
		int imageId =  Integer.parseInt(cycle.getParameter("imageId"));
		byte imageData[] = ImageDB.loadImage(imageId, 
				infrastructure
				.getApplicationPropertySource()
				.getPropertyValue("com.ttdev.album.image-folder"));
		response.setHeader("Content-disposition", "attachment; filename=foo.jpg");
		response.setContentType("image/jpeg");
		response.setContentLength(imageData.length);
		try {
			OutputStream out = response.getOutputStream();
			out.write(imageData);
		} catch (IOException e) {
			throw new ApplicationRuntimeException(e);
		}
	}
	public ILink getLink(boolean post, Object parameter) {
		String imageId = (String)((Object[])parameter)[0];
		Map parameters = new HashMap();
		parameters.put("imageId", imageId);
		return linkFactory.constructLink(this, post, parameters, false);
	}

}