ExtJS+SpringMVC文件上传与下载

说到文件上传、下载功能，网络上大多介绍的是采用JSP、SpringMVC或者Struts等开源框架的功能，通过配置达到文件上传、下载的目地。可是最近项目要用到文件上传与下载的功能，因为本项目框架采用开源框架SpringMVC、ExtJS、Hibernate写成的，当然借助SpringMVC框架本身的文件上传与下载也可以，但是同样需要和以前一样，编写一些配置文件，所以最近自己搞了一下关于ExtJS、SpringMVC的免配置文件上传与下载的功能研究。

        提起文件上传，免不了客户端（提交文件）和服务器端（接收文件）的结合。

        首先定义全局相关变量：

/**
 * @author:limingzhong
 * @desc:定义相关全局静态变量
 * @Date:2012-02-28
 */
private final static String UPLOAD_SUCCESS = "{success:true,mess:'文件上传成功!'}";

private final static String UPLOAD_FAILURE = "{success:false,mess:'文件上传失败!'}";

private final static String FILE_NO = "{success:false,mess:'文件不存在!'}";

private final static String FILE_YES = "{success:true,mess:'文件存在!'}";

private final static String CONTENT_TYPE = "text/html;charset=gb2312";

private final static String APPLICATION = "application/octet-stream";

        客户端：采用ExtJS的formPanel提交功能

var excelUpload = new Ext.form.TextField({
    id:'excelUpload',
    anchor:'90%',
    height:30,
    350,
    name:'file',
    inputType:'file',
    fieldLabel:'文件选择'
});

var formPanel = new Ext.form.FormPanel({
    labelWidth:80,
    bodyStyle:'padding:5 5 5 5',
    height:515,
    200,
    frame:true,
    fileUpload:true,
    items:[excelUpload]
});

// 定义按钮
var upLoadFile = new Ext.Toolbar.Button({
    text:'上传'
});

// 下载数据功能
var up = function(bt) {
    var excelName = Ext.getCmp('excelUpload').getRawValue();// 上传文件名称的路径
    if (excelName == ""){
        Ext.Msg.show({title:'提示',msg:'请选择文件!',buttons:Ext.Msg.OK,icon:Ext.MessageBox.INFOR});
        return;
    }else {
        var array = new Array();
        array = excelName.split("\");
        var length = array.length;
        var fileName = "";
        var index = 0;
        for (index = 0; index < length; index++) {
            if (fileName == "") {
                fileName = array[index];
            } else {
                fileName = fileName + "/" + array[index];
            }
        }

        formPanel.getForm().submit({
            url:'http://localhost:8080/pro/upload.json',
            method:'POST',
            waitMsg:'数据上传中, 请稍等...',
            success:function(form, action, o) {
                Ext.MessageBox.alert("提示信息",action.result.mess);
            },
            failure : function(form, action) {
                Ext.MessageBox.alert("提示信息","请求失败,文件上传失败");
            }
        });
    }
}

// 添加按钮的响应事件
upLoadFile.addListener('click', up, false);

var window = new Ext.Window({
    title:'上传文件',
    500,
    height:200,
    minWidth:500,
    minHeight:200,
    layout:'fit',
    plain:true,
    modal:true,
    //closeAction:'hide',
    bodyStyle:'padding:5px;',
    buttonAlign:'center',
    items:formPanel,
    buttons:[upLoadFile]
});
window.show();

       服务器端：根据SpringMVC注解直接调用对应方法，采用流的形式上传文件，这样直接避免配置xml等文件的麻烦。

/**
 * @author:limingzhong
 * @throws:IOException
 * @desc:上传文件
 * @params:自带参数,客户端不传入实参
 * @Date:2012-02-28
 */
@RequestMapping(value = "/upload.json")
public void upLoad(HttpServletRequest request,HttpServletResponse response) throws IOException {

    response.setContentType(CONTENT_TYPE);
    PrintWriter out = response.getWriter();

    if (!ServletFileUpload.isMultipartContent(request)){
        out.println(UPLOAD_FAILURE);
    }

    String name = null;
    try {
        DiskFileItemFactory factory = new DiskFileItemFactory();
        factory.setSizeThreshold(4096);
        ServletFileUpload upload = new ServletFileUpload(factory);
        upload.setSizeMax(4 * 1024 * 1024);
        Iterator<?> iter = upload.parseRequest(request).iterator();
        while (iter.hasNext()) {
            FileItem item = (FileItem) iter.next();
            if (item.isFormField()) {
                name = item.getFieldName();
                out.println(UPLOAD_FAILURE);
            } else {
                name = item.getName();
                String path = getPath();
                if(path==null || path==""){
                    out.println(UPLOAD_FAILURE);
                }else{
                    item.write(new File(path+name.substring(name.lastIndexOf(File.separator)+1,name.length()))); //保存上传文件
                    out.println(UPLOAD_SUCCESS);
                }
            }
        }
        out.close();
    } catch (Exception e) {
        out.println(UPLOAD_FAILURE);
        out.close();
    }
}

       至此，文件上传的功能已结束。

       下面把下载功能的客户端和服务器端的代码贴出来，以供大家拍砖：

       客户端：

window.location.href = 'http://127.0.0.1:8080/pro/down.json?fileName='+encodeURI(encodeURI(fileName));

       服务器端：

/**
 * @author:limingzhong
 * @throws:IOException
 * @desc:下载文件
 * @params:fileName-文件名称
 * @Date:2012-02-28
 */
@RequestMapping(value = "/down.json")
public void down(@RequestParam("fileName") String fileName,HttpServletRequest request,HttpServletResponse response) throws IOException {
    response.setContentType(APPLICATION);
    fileName = URLDecoder.decode(fileName, "utf-8");
    String path = getPath()+fileName;
    path = path.replace("%20", " ");
    File file = new File(path);

    // 清空response
       response.reset();

       // 设置response的Header
       response.addHeader("Content-Disposition", "attachment;filename=" + new String(fileName.getBytes("gbk"),"iso8859-1"));
       response.addHeader("Content-Length", "" + file.length());

    try{
        //以流的形式下载文件
        InputStream fis = new BufferedInputStream(new FileInputStream(path));
        byte[] buffer = new byte[fis.available()];
        fis.read(buffer);
        fis.close();

        OutputStream toClient = new BufferedOutputStream(response.getOutputStream());
        toClient.write(buffer);
        toClient.flush();
        toClient.close();
    }catch(Exception e){
        e.printStackTrace();
    }
}

      至此，文件下载的功能已结束。

来自：http://blog.csdn.net/limingzhong198/article/details/7324570