解決當FORM的ENCTYPE="multipart/form-data" 時request.getParameter()獲取不到值的方法

部分轉載於:

http://blog.csdn.net/georgejin/article/details/1706647

http://www.cnblogs.com/loveyunk/p/6089032.html 

http://www.cnblogs.com/greenteaone/p/4186619.html

 from表單中向后台傳遞參數的同時要上傳文件，所以ENCTYPE="multipart/form-data" 必須要加在form里面,可是這樣的話，我在servlet里面用request.getParameter()方法無論如何都只是獲得null值.

我這里使用的是commons fileupload的jar包(commons-fileupload-1.2.jar).

 先附錄之前寫的上傳文件的工具類:

public class FileUploadAndDown {
    
    private Logger logger = Logger.getLogger(FileUploadAndDown.class);
    
    public String upload(ServletConfig servletconfig, HttpServletRequest request)throws FileUploadException{
        HttpSession session = request.getSession();
        String username = session.getAttribute("username").toString();
        DiskFileUpload fu = new DiskFileUpload();
        // 判斷表單是否設置了mutipart/form-data
        boolean isMultipart = DiskFileUpload.isMultipartContent(request);
        if (!isMultipart){
            return null;
        }else{
            fu.setHeaderEncoding(request.getCharacterEncoding());
            // 設置允許用戶上傳文件大小,單位:字節
            fu.setSizeMax(10*1024*1024);
            // 設置最多只允許在內存中存儲的數據,單位:字節
            fu.setSizeThreshold(4*1024*1024);
            // 設置一旦文件大小超過getSizeThreshold()的值時數據存放在硬盤的目錄
            String temp = System.getProperty("user.home")+File.separator+"catalogupload";
            fu.setRepositoryPath(temp);
            File file = new File(temp);
            if (!file.exists() || !file.isDirectory()) {
                file.mkdir();
            }
            // 開始讀取上傳信息

            List fileItems = fu.parseRequest(request);
            // 依次處理每個上傳的文件

            Iterator iter = fileItems.iterator();
            // 如果需要上傳多個文件，將if改稱while即可
            while(iter.hasNext()) {
                FileItem item = (FileItem) iter.next();
                // 忽略其他不是文件域的所有表單信息

                if (!item.isFormField()) {
                    String name = item.getName();
                    String time = DateUtil.getDateTime("yyyyMMddHHmmss");
                    name = username + "_" + time + FileNameUtil.extractFileExt(name);
                    try {
                        String namepath = servletconfig.getServletContext().getRealPath("poster");
                        file = new File(namepath);
                        if(!file.exists()){
                            file.mkdirs();
                        }
                        name = namepath+File.separator+name;
                        item.write(new File(name));
                        logger.info("上傳海報名為:" + name);
                        return name;
                    } catch (Exception e) {
                        logger.error("上傳海報保存異常" + e.getMessage());
                        return null;
                    }
                }
            }
        }
        return "";
    }
}

 

對應的jsp頁面

        <form name="form1" action="deleteMmobject.do" method="post" enctype="multipart/form-data" target="displayprocess" >
            導入要刪除列表文件 &nbsp;&nbsp;&nbsp;    
            <input type="hidden" id="deleteFlagHidden" name="deleteFlagHidden" value="" />
            <input type="hidden" name="action" value="" />
            
            <input type="file" name="filepath" />
            <input name="deleteMmobject_radio" id="selfDelete" type="radio" value="自刪除" onclick="selfDeleteFun()"; checked />自刪除
            <input name="deleteMmobject_radio" id="sendToBoDelete" type="radio" value="同時下發刪除到下游" onclick="sendToBoDeleteFun()" />同時下發刪除到下游
            <input type="button" value="確定" onclick="deleteFun()"/>
            <!-- <input type="submit"  value="確定" /> -->
        </form>

 

通過servlet里面用request.getParameter("id名稱")方法無論如何都只是獲得null值.   通過更換上傳依賴的jar包(jspsmartupload.jar)

新加代碼如下:

    public Map<String,String> uploadUseJspSmart(ServletConfig servletconfig, HttpServletRequest request, HttpServletResponse response)throws FileUploadException{
        Map<String,String> uploadParametersMap = new HashMap<String,String>(); 
        HttpSession session = request.getSession();
        String username = session.getAttribute("username").toString();
        
        com.jspsmart.upload.SmartUpload smartUpload = new com.jspsmart.upload.SmartUpload();
        File file = null;
        String fileName = null;
        try {
            smartUpload.initialize(servletconfig, request, response);
            smartUpload.setTotalMaxFileSize(100000000);
            smartUpload.setAllowedFilesList("txt,excel");
            smartUpload.setDeniedFilesList("exe,bat,jsp,htm,html,,");
            
            smartUpload.upload();
            // 得到上傳的文件對象
            com.jspsmart.upload.File smartFile = smartUpload.getFiles().getFile(0);
            
            fileName = smartFile.getFileName();
            String time = DateUtil.getDateTime("yyyyMMddHHmmss");
            fileName = username + "_" + time + FileNameUtil.extractFileExt(fileName);
            String namepath = System.getProperty("user.home")+File.separator+"catalogupload";
            
            file = new File(namepath);
            if(!file.exists()){
                file.mkdirs();
            }
            fileName = namepath+File.separator+fileName;
            smartFile.saveAs(fileName);
            logger.info("通過JspSamrt上傳文件名為:" + fileName+"成功");
            //這里可以順利得到jsp頁面form表單中對應的"deleteFlagHidden"參數
            String deleteFlagHidden = smartUpload.getRequest().getParameter("deleteFlagHidden");
            uploadParametersMap.put("fileName", fileName);
            uploadParametersMap.put("deleteFlagHidden", deleteFlagHidden);
            return uploadParametersMap;
        } catch (Exception e1) {
            e1.printStackTrace();
            logger.info("通過JspSamrt上傳文件名為:" + fileName+"失敗");
        }
        return null;
    }