DWR3.0 文件上传

最新推荐文章于 2022-01-26 23:04:51 发布

原创最新推荐文章于 2022-01-26 23:04:51 发布 · 181 阅读

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#DWR #文件上传

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本文介绍如何利用DWR 3.0进行文件上传操作，详细讲解了使用FileTransfer类作为参数的方法实现，并提供了从前端页面到后端处理的完整示例代码。

DWR3.0 文件上传

引自：http://tyyler.blog.51cto.com/4030931/730599

java方法中的参数必须是BufferedImage，InputStream，FileTransfer三种中其中一个，

一般推荐使用FileTransfer，可以获取文件名、文件大小、和内置的inputStream。

后台实现文件上传方法

    public String fileUploadForDwr(ArrayList<FileTransfer> fileTransfer) {

            String tmp = "error";

            String fileName = ""; // 文件名

            String newFileName = ""; // 新文件名

            InputStream streamIn = null;

            OutputStream streamOut = null;

            long size = 1024 * 1024 * 5;

            if(fileTransfer.size() > size){

                return "文件不得大于5M";

            }

            WebContext webContext = WebContextFactory.get();
            String saveurl = webContext.getHttpServletRequest().getSession()
                    .getServletContext().getRealPath("/upload");
            for (FileTransfer obj : fileTransfer) {
                if (obj.getFilename() != null && !obj.getFilename().equals("")) {
                    fileName = obj.getFilename();
                    if (fileName.lastIndexOf("\\") > -1) {
                        fileName = fileName
                                .substring(fileName.lastIndexOf("\\") + 1);
                    }
                    System.out.println(fileName);
                    newFileName = ""
                            + fileName.substring(fileName.indexOf("."));
                    try {

                        streamIn = obj.getInputStream();
                        streamOut = new FileOutputStream(new File(saveurl,
                                newFileName));
                        int bytesRead = 0;
                        byte[] buffer = new byte[81920];
                        while ((bytesRead = streamIn.read(buffer, 0, 81920)) != -1) {
                            streamOut.write(buffer, 0, bytesRead);
                        }
                        streamOut.close();
                        streamIn.close();
                        tmp="success";
                    } catch (FileNotFoundException ex) {

                    } catch (IOException e) {
                        // TODO: handle exception
                    } finally {

                        streamIn = null;
                        streamOut = null;
                    }

                }
            }
            return tmp;
        }

前台调用页面：

    <%@ page language="java" import="java.util.*" pageEncoding="GBK"%>

    <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
    <html>
        <head>

            <title>dwr3 文件上传</title>

            <meta http-equiv="pragma" content="no-cache">
            <meta http-equiv="cache-control" content="no-cache">
            <meta http-equiv="expires" content="0">
            <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
            <meta http-equiv="description" content="This is my page">

            <script type="text/javascript" src="/dwr/engine.js"></script>
            <script type="text/javascript" src="/dwr/util.js"></script>
            <script type="text/javascript" src="/dwr/interface/dwrFileUtil.js"></script>

            <script type="text/javascript">

             //解决谷歌浏览器无法上传的问题
             var isChrome = (/\bchrome\b/).test(navigator.userAgent.toLowerCase());
    dwr.engine.transport.iframe.loadingComplete = function(batchId) {
    var batch = dwr.engine._batches[batchId];
    if(!isChrome)
    if (batch) dwr.engine.batch.validate(batch);
    };
               function uploadFile(){
                 var file=dwr.util.getValue("attach");
                 var str="123"
                 var fileArr = new Array();//注意这里是用的集合，无论一个附件还是多个附件都可以了
                 fileArr[0] = file;
                 dwrFileUtil.fileUploadForDwr(fileArr,{callback:function (data){back(str,data)}});
               }

               function back(tmp,data){
                 alert(3);
                 alert(tmp+""+data);

               }
            </script>
        </head>

        <body>
            <input type="file" name="attach">
            <br />
            <input type="button" name="btnSub" onclick="uploadFile()" value="文件上传">
        </body>
    </html>

DWR 配置：

    <create creator="new" javascript = "dwrFileUtil">
        <param name="class" value="FileUpload" />
        <include method = "fileUploadForDwr" />
    </create>