JSF之上传图片(也可以用来上传其他文件)

最新推荐文章于 2017-07-24 15:50:00 发布

原创最新推荐文章于 2017-07-24 15:50:00 发布 · 932 阅读

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CC 4.0 BY-SA版权

文章标签：

#jsf #string #null #byte #file #buffer

本文介绍了一种使用JavaScript和Java实现的图片上传方法，该方法通过文件流而非组件完成图片上传。此外，还实现了图片预览功能，并详细展示了如何验证图片格式及处理上传过程中的各种细节。

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没用组件来上传，是用的流来上传的

<%@ taglib uri="http://myfaces.apache.org/tomahawk" prefix="x"%>
<h:form enctype="multipart/form-data">
图片：<x:inputFileUpload id="fileId" value="#{picBean.myfile}" storage="file" onchange="showPic()"/>
     <img id="picId" height="30 width="30" />
     <script type="text/javascript">
         function showPic(){
            var file= document.getElementById('addForm:fileId');
            var pic=document.getElementById('picId');
            pic.src=file.value;
         }
        </script>

PicBean.java
// 上传图片和类型不能为空
  if (myfile != null) {
   String fileName = new File(myfile.getName()).getName();
   String test = myfile.getContentType();
   if (!test.startsWith("image/")) {
    wrongpictype = "图片格式不对";
    return "";
   }
   String path=UploaderHelper.uploadFileToDisk(myfile);
   this.picnews.setTurl(path);
  }

附
UploaderHelper.java
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import javax.faces.context.FacesContext;
import javax.servlet.http.HttpSession;
import org.apache.myfaces.custom.fileupload.UploadedFile;
public class UploaderHelper {
public final static String uploadPath="uploadFile";

public static String uploadFileToDisk(UploadedFile myFile)
{
  try {
   long time = System.currentTimeMillis();
   InputStream in = myFile.getInputStream();
   FacesContext ctx = FacesContext.getCurrentInstance();
   HttpSession hs = (HttpSession) ctx.getExternalContext().getSession(true);
   String directory = hs.getServletContext().getRealPath("//")+uploadPath;
   File fileDir = new File(directory);
   if (!fileDir.exists()) {
    fileDir.mkdir();
   }
   String fileName=String.valueOf(Thread.currentThread().getContextClassLoader().hashCode())+"_"+time+myFile.getName().substring(myFile.getName().lastIndexOf("."));
   String file = hs.getServletContext().getRealPath("//") + uploadPath+"//"+ fileName;
   BufferedOutputStream out = new BufferedOutputStream(new FileOutputStream(file));
   byte[] buffer = new byte[1024 * 2];
   int length;
   while ((length = in.read(buffer, 0, buffer.length)) > 0) {
    out.write(buffer, 0, length);
   }
   out.flush();
   out.close();
   return uploadPath+"/"+ fileName;
//   return "//" + uploadPath+"//"+ fileName;
  } catch (Exception e) {
   e.printStackTrace();
  }
  return null;
}

public String downLoadFile()
{
  String blobId=FacesUtils.getRequestParameter("blobFileID");
  BlobFile blobVO=blobFileService.getBlobFile(Integer.parseInt(blobId));
  HttpServletResponse response = (HttpServletResponse) FacesContext.getCurrentInstance().getExternalContext().getResponse();
  ServletContext servletContext=FacesUtils.getServletContext();
        InputStream s = new java.io.ByteArrayInputStream(blobVO.getFileContent());
        BufferedInputStream bis = new BufferedInputStream(s);
        String realName=blobVO.getName();
        String extendName=null;
        try {
            String mimeType = null;
            int pos = realName.lastIndexOf(".");
            if (pos >= 0 && (pos + 1) < realName.length()) {
                extendName = realName.substring(pos + 1);
            }
            if (extendName != null)
                mimeType = servletContext.getMimeType(extendName);
            if (mimeType == null)
                mimeType = "APPLICATION/OCTET-STREAM";

            response.setContentType(mimeType);
            response.setHeader("Content-Disposition", "attachment; filename=/"" + URLEncoder.encode(realName, "UTF-8") + "/"");
            byte[] data = new byte[1024];
            OutputStream out = response.getOutputStream();
            int length=0;
            do {
                length = bis.read(data);
                if (length != -1) {
                    out.write(data, 0, length);
                }
            } while (length > 0);
            out.flush();
            out.close();
            data = null;
            //
            response.setStatus(HttpServletResponse.SC_OK);
            response.flushBuffer();
        } catch (IOException ex) {
            response.setContentType("text/html");
            response.setHeader("Content-Disposition", "");
        } finally {
            try {
                if (bis != null)
                    bis.close();
            } catch (IOException ex) {
            }
        }
        FacesContext.getCurrentInstance().responseComplete();
  return null;
}

  public String downLoadFileFromDisk()
{
//  String blobId=FacesUtils.getRequestParameter("blobFileID");
//  BlobFile blobVO=blobFileService.getBlobFile(Integer.parseInt(blobId));
  String filepath=FacesUtils.getRequestParameter("filepath");;
  String realName=FacesUtils.getRequestParameter("realName");;
  HttpServletResponse response = (HttpServletResponse) FacesContext.getCurrentInstance().getExternalContext().getResponse();
  ServletContext servletContext=FacesUtils.getServletContext();
        InputStream s=null;
  try {
   s = new BufferedInputStream(new FileInputStream(filepath));
  } catch (FileNotFoundException e) {
   e.printStackTrace();
  }
        BufferedInputStream bis = new BufferedInputStream(s);
        String extendName=null;
        try {
            String mimeType = null;
            int pos = realName.lastIndexOf(".");
            if (pos >= 0 && (pos + 1) < realName.length()) {
                extendName = realName.substring(pos + 1);
            }
            if (extendName != null)
                mimeType = servletContext.getMimeType(extendName);
            if (mimeType == null)
                mimeType = "APPLICATION/OCTET-STREAM";