jquery的Uploadify控件上传图片和预览使用介绍。

   在简单的servlet系统中和在SSH框架中，后台处理不同的，在三大框架中图片预览时费了不少力气，所以下面将两种情况都介绍一下。

   1，前台代码

script：

$("#uploadify").uploadify({
	'langFile'       : '<%=request.getContextPath()%>/config/juploadify/uploadifyLang_cn.js',
	'swf'       	 : '<%=request.getContextPath()%>/config/juploadify/uploadify.swf',
	'uploader'       : '<%=request.getContextPath()%>/UploadAction/uploadImg.action', //图片上传的action方法
	'queueID'        : 'fileQueue',
	'auto'           : true,
	'multi'          : true,
	'buttonCursor'   : 'hand',
	'fileObjName'    : 'uploadify',
	'buttonText'	 : '上传图片',
	'height'         : '25',
	'progressData' 	 : 'percentage',
	'fileTypeDesc'   : '支持格式:jpg/gif/jpeg/png/bmp.',  
	'fileTypeExts': '*.jpg;*.gif;*.jpeg;*.png;*.bmp',//允许的格式
	onUploadSuccess  : function(file,data,response) {
		//设置图片预览
		var _arr_val = data.split(",");
		$("#photo").val(_arr_val[1]);
		$("#pic_view").attr("src","<%=request.getContextPath()%>" + _arr_val[1]);
	}
});

<td width="15%" rowspan="9" align="center">
	<div id="fileQueue" style="width:200px;"></div> 
	<input type="file" name="uploadify" id="uploadify" /> 
	<input type="hidden" name="photo" id="photo" value=http://www.mamicode.com/"">>
   2，servlet中后台处理
public void uploadImg(){
	// 解决服务器端消息返回客户端后中文字符乱码
	response.setHeader("Content-Type", "text/html;charset=UTF-8");
	HttpSession session = request.getSession();
	PrintWriter outs = response.getWriter();

	//获取上传图片的路径
	String savePath = request.getSession().getServletContext().getRealPath("");
	String saveDirectory = savePath + "/Imgupload";
	File file = new File(saveDirectory);
	if (!file.exists()) {
	    file.mkdirs();
	}

	//设置图片大小
	if (StringUtils.isBlank(this.fileSizeLimit.toString())) {
		this.fileSizeLimit = "100";// 默认100M
	}
	int maxPostSize = Integer.valueOf(this.fileSizeLimit).intValue() * 1024 * 1024;

	String encoding = "UTF-8";
	MultipartRequest multi = null;
	try {
		multi = new MultipartRequest(request, saveDirectory, maxPostSize, encoding);
	} catch (Exception e) {
		System.out.println("发生异常：" + e.getMessage());
		return;
	}

	//图片预览功能实现
	String _result = "";
	Enumeration files = multi.getFileNames();
	while (files.hasMoreElements()) {
		String name = (String) files.nextElement();
		File f = multi.getFile(name);
		if (f != null) {
			String fileName = multi.getFilesystemName(name);
			String lastFileName = saveDirectory + "/" + fileName;
			result += multi.getOriginalFileName(name) + "," + savePath + "/" + fileName;
		}
	}

	outs.print(_result);
}

  注意：action方法返回的字符串为图片的名称和图片的路径。

     3，SSH框架中使用
     
package cn.com.zzcy.base.action;

import java.io.File;

@Namespace("/UploadAction")
public class UploadAction {
	private File uploadify;
	public File getUploadify() {
		return uploadify;
	}
	public void setUploadify(File uploadify) {
		this.uploadify = uploadify;
	}
	private String uploadifyFileName;
	public String getUploadifyFileName() {
		return uploadifyFileName;
	}
	public void setUploadifyFileName(String uploadifyFileName) {
		this.uploadifyFileName = uploadifyFileName;
	}

	/**
	 * 上传图片
	 * @throws IOException 
	 */
	@Action("uploadImg")
	public void uploadImg(){
		HttpServletRequest request = ServletActionContext.getRequest();
		HttpServletResponse response = ServletActionContext.getResponse();
		String savePath = request.getSession().getServletContext().getRealPath("");
		PrintWriter out = null;
		String resultStr = "";
		String extName = "";// 扩展名
		String newFileName = "";// 新文件名
		try {
			response.setCharacterEncoding("utf-8");
			out = response.getWriter();
			
			//获取文件的扩展名
			if (uploadifyFileName.lastIndexOf(".") >= 0) {
				extName = uploadifyFileName.substring(uploadifyFileName.lastIndexOf("."));
			}
			//根据当前时间生成新的文件名称
			String nowTime = new SimpleDateFormat("yyyymmddHHmmss").format(new Date());// 当前时间
			newFileName = nowTime + extName;
			
			//设置文件保存路径
			String param = request.getParameter("param");
			savePath = savePath + "/ImgUpload/"+param+"/";
			File file = new File(savePath);
			if(!file.exists()){
				file.mkdirs();
			}
			uploadify.renameTo(new File(savePath+newFileName));
			resultStr = uploadifyFileName+","+"/ImgUpload/"+param+"/"+newFileName;
		} catch (IOException e) {
			e.printStackTrace();
		}finally{
			out.print(resultStr);
		}
    }
			
}

     注意：要定义局部变量并提供set方法，这样图片的名称和信息才能自动注入进入。
     这里通过request方法获取不到图片信息。。。
            
     4，实现的效果图如下：
     
Uploadify 控件上传图片 + 预览