Tapestry 5 프레임 워 크 에서 파일 다운로드 기능 구현

Tapestry 5 프레임 워 크 에서 파일 다운로드 기능 을 실현 하고'text/xml','text/html'ContentType 형식 이 아 닌 출력 을 합 니 다.
주:(기본적으로 Tapestry 5 는 text/html 를 출력 합 니 다.text/xml 를 출력 하려 면 페이지 클래스 설명 전에 주석 을 추가 해 야 합 니 다.@Meta("tapestry.response-content-type=text/xml")
다음은 Tapestry 5 파일 흐름 요청/응답 코드 예제 입 니 다.아래 클래스 만 컴 파일 하면 TML 파일 이 필요 없습니다.
This example is very similar to the examples on Streaming a Dynamic PDF or a Dynamic chart. Except in this case the file already exists somewhere. I'll also show some utility classes I made up to assist in the process.
ImagePage.java
This is the page class in your Tapestry 5 application

import java.io.InputStream;

import com.mycompany.myapp.wui.tapestry.services.util.JPEGAttachment;

import org.apache.tapestry.StreamResponse;
 public class ImagePage {
        public StreamResponse onSubmit() {
                //Note that you could provide an absolute path here, like H:\\LOLCATZ.MP3
                InputStream input = ImagePage.class.getResourceAsStream("HelloKitty.jpg"); 
                return new JPEGAttachment(input);
        }
}

JPEGAttachment.java

import java.io.InputStream;

public class JPEGAttachment extends AttachmentStreamResponse {
        public JPEGAttachment(InputStream is, String args) {
                super(is, args);
                this.contentType = "image/jpeg";
                this.extension = "jpg";
        }

        public JPEGAttachment(InputStream is) {
                super(is);
                this.contentType = "image/jpeg";
                this.extension = "jpg";
        }
}

AttachmentStreamResponse.java
This is a util class for Attachments. The goal here is to have a "Save As" dialog pop up on the client browser.

import java.io.IOException;
import java.io.InputStream;

import org.apache.tapestry.StreamResponse;
import org.apache.tapestry.services.Response;

public class AttachmentStreamResponse implements StreamResponse {
        private InputStream is = null;

        /**
         * This can be changed to something obscure, so that it is more likely to trigger a "Save As" dialog, although there
         * is no guarantee.
         * 
         * ex: application/x-download
         * 
         * See http://www.onjava.com/pub/a/onjava/excerpt/jebp_3/index3.html
         */
        protected String contentType = "text/plain";

        protected String extension = "txt";

        protected String filename = "default";

        public AttachmentStreamResponse(InputStream is, String filenameIn) {
                this.is = is;
                if (filenameIn != null) {
                        this.filename = filenameIn;
                }
        }

        public AttachmentStreamResponse(InputStream is) {
                this.is = is;
        }

        public String getContentType() {
                return contentType;
        }

        public InputStream getStream() throws IOException {
                return is;
        }

        public void prepareResponse(Response arg0) {
                arg0.setHeader("Content-Disposition", "attachment; filename=" + filename + ((extension == null) ? "" : ("." + extension)));
                arg0.setHeader("Expires", "0");
                arg0.setHeader("Cache-Control", "must-revalidate, post-check=0, pre-check=0");
                arg0.setHeader("Pragma", "public");
                //We can't set the length here because we only have an Input Stream at this point. (Although we'd like to.)
                //We can only get size from an output stream.  arg0.setContentLength(.length);
        }
}

InlineStreamResponse.java
This file is not used in the example, but is for files you intend to display inline in the browser (No "Save As" dialog box):

import java.io.IOException;
import java.io.InputStream;

import org.apache.tapestry.StreamResponse;
import org.apache.tapestry.services.Response;

public class InlineStreamResponse implements StreamResponse {
        private InputStream is = null;

        protected String contentType = "text/plain";// this is the default

        protected String extension = "txt";

        protected String filename = "default";

        public InlineStreamResponse(InputStream is, String... args) {
                this.is = is;
                if (args != null) {
                        this.filename = args[0];
                }
        }

        public String getContentType() {
                return contentType;
        }

        public InputStream getStream() throws IOException {
                return is;
        }

        public void prepareResponse(Response arg0) {
                arg0.setHeader("Content-Disposition", "inline; filename=" + filename
                                + ((extension == null) ? "" : ("." + extension)));
        }
}

Other file types
Now, all you have to do for other file types is create a class like this:
For a JPG inline

import java.io.InputStream;

public class JPEGInline extends InlineStreamResponse {
        public JPEGInline(InputStream is, String... args) {
                super(is, args);
                this.contentType = "image/jpeg";
                this.extension = "jpg";
        }
}

For an XLS attachment

public class XLSAttachment extends AttachmentStreamResponse {
        public XLSAttachment(InputStream is, String args) {
                super(is, args);
                this.contentType = "application/vnd.ms-excel";
                this.extension = "xls";
        }
}

For a PDF attachement

import java.io.InputStream;

public class PDFAttachment extends AttachmentStreamResponse {
        public PDFAttachment(InputStream is, String args) {
                super(is, args);
                this.contentType = "application/pdf";
                this.extension = "pdf";
        }

        public PDFAttachment(InputStream is) {
                super(is);
                this.contentType = "application/pdf";
                this.extension = "pdf";
        }
}

Calling the event handler from a page template
The event handler can be called using an actionLink e.g. download pdf but the event handler can can also be called from an expansion, for example if you want to embed a dynamically generated/retrievd image in a page - ${embedImage()}. When the page renders the event handler will be called