flex与java集成下载功能实现

 适用于附件放在数据库中的下载方式

 flex端：

navigateToURL(new URLRequest("URL.do"+id), "_blank"); --发送的请求路径

java端:

 

package com.zjht.hrm.action;

import java.io.BufferedOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.io.PrintWriter;
import org.apache.commons.codec.binary.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import nl.bitwalker.useragentutils.Browser;
import nl.bitwalker.useragentutils.UserAgent;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;

import com.zjht.hrm.dao.AttachmentDao;
import com.zjht.hrm.model.Attachment;

@Controller
public class AttachmentDownloadAction {

    private AttachmentDao attachmentDao;

    @RequestMapping(value = "AttachmentDownload", method = RequestMethod.GET)
    public void attachmentDownloadById(final long id, final boolean fail,
            final HttpServletRequest request, final HttpServletResponse response) {
        Attachment entity = null;
        try {
            entity = attachmentDao.findById(id);
            if(entity==null){
                try {
                    response.sendError(HttpServletResponse.SC_FORBIDDEN);
                    return;
                } catch (IOException e) {
                }
            }
            byte[] data = entity.getContent();
            String fileName = entity.getFileName() == null ? "" : entity
                    .getFileName();
            if (isImage(entity.getFileType()) && !fail) {
                //imageDownload(request, response, entity);
                PrintWriter out = response.getWriter();
                out.println("<img src=\"AttachmentDownload.do?id="+entity.getId()
                        +"&fail=true\" />");
                out.flush();
                out.close();
                return;
            }
            response.reset();
            response.setStatus(200);
            FileType fileType=getFileType(entity.getFileType());
            UserAgent userAgent = UserAgent.parseUserAgentString(request
                    .getHeader("user-agent"));
            if (userAgent.getBrowser().getGroup() == Browser.IE)
                fileName=java.net.URLEncoder.encode(fileName,"UTF-8");
            else
                fileName = new String(fileName.getBytes("UTF-8"),"ISO8859_1");
            if(fileType==FileType.img || fileType==FileType.pdf)
            {
                response.setHeader("Content-Disposition", "inline; filename=\""
                        + fileName + "\"");
            }else{
                response.setHeader("Content-Disposition", "attachment; filename=\""
                        + fileName + "\"");
            }
            response.addHeader("Content-Length", "" + data.length);
            response.setHeader("Connection", "close");
            response.setContentType(getContentType(entity.getFileType()));
            OutputStream outputStream = new BufferedOutputStream(
                    response.getOutputStream());
            outputStream.write(data);
            outputStream.flush();
            outputStream.close();
        } catch (Exception e1) {
            try {
                response.sendError(HttpServletResponse.SC_FORBIDDEN);
            } catch (IOException e) {
            }
        }

    }

    @SuppressWarnings("unused")
    private void imageDownload(final HttpServletRequest request,
            final HttpServletResponse response, Attachment entity)
            throws IOException {
        PrintWriter out = response.getWriter();
        UserAgent userAgent = UserAgent.parseUserAgentString(request
                .getHeader("user-agent"));
        if (userAgent.getBrowser() == Browser.IE5
                || userAgent.getBrowser() == Browser.IE5_5
                || userAgent.getBrowser() == Browser.IE6
                || userAgent.getBrowser() == Browser.IE7) {
            out.println("<img src=\"AttachmentDownload.do?id="+entity.getId()
                    +"&fail=true\" />");

        } else {
            String content = Base64.encodeBase64String(entity.getContent());
            out.println("<img src=\"data:image/" + entity.getFileType()
                    + ";base64," + content + "\" />");
        }
        out.flush();
        out.close();
    }

    public void setAttachmentDao(AttachmentDao attachmentDao) {
        this.attachmentDao = attachmentDao;
    }

    private String getContentType(String extension) {
        FileType fileType = null;
        try {
            fileType = Enum.valueOf(FileType.class, extension);
        } catch (Exception e) {
            return "application/octet-stream;charset=UTF-8";
        }
        switch (fileType) {
        case xls:
            // contentType设定
            return "application/vnd.ms-excel;charset=utf-8";
        case xlsx:
            // contentType设定
            return "application/vnd.ms-excel;charset=utf-8";
        case pdf:
            // contentType设定
            return "application/pdf;charset=utf-8";
        case doc:
            // contentType设定
            return "application/msword;charset=utf-8";
        case docx:
            // contentType设定
            return "application/msword;charset=utf-8";
        case txt:
            // contentType设定
            return "text/plain;charset=utf-8";
        default:
            // contentType设定
            return "application/octet-stream;charset=UTF-8";
        }
    }

    public enum FileType {
        xls("xls"), xlsx("xlsx"), pdf("pdf"), doc("doc"), docx("docx"), txt(
                "txt"),gif("gif"),jpeg("jpeg"),jpg("jpg"),png("png"),img("img");

        FileType(String name) {
            this.name = name;
        }

        private String name;

        public String getName() {
            return name;
        }

        public void setName(String name) {
            this.name = name;
        }
    }

    private FileType getFileType(String extension){
        FileType fileType = null;
        try {
            fileType = Enum.valueOf(FileType.class, extension);
        } catch (Exception e) {
            return null;
        }
        switch (fileType) {
        case pdf:
            return fileType;
        case gif:
            return FileType.img;
        case jpeg:
            return FileType.img;
        case jpg:
            return FileType.img;
        case png:
            return FileType.img;
        default:
            return null;
        }
    }


    private boolean isImage(String fileType) {
        if (fileType.equals("png") || fileType.equals("gif")
                || fileType.equals("jpg")) {
            return true;
        } else {
            return false;
        }
    }
}