grails 文件的上传和下载

引用

1.gsp 上传页面代码

 <g:form controller="document" action="upload" method="post" enctype="multipart/form-data">
   <input type="file" name="myFile" />                        <g:select name="purCategory.id" from="${purcatelist}" optionKey="id" value="${documentInstance?.purCategory?.id}"  />
  <input type="submit" value="上&nbsp;&nbsp;&nbsp;传" />
      </g:form>
注：enctype="multipart/form-data" 必须要写

引用

2.controller 里的代码

def upload = {
        def documentInstance = new Document(params)
        def url = params.myFile
        // println url

        def f = request.getFile('myFile')
        if(!f.empty) {
            def webRootDir = servletContext.getRealPath("/")
            println webRootDir
            def userDir = new File(webRootDir, "/payload/")
            userDir.mkdirs()
            f.transferTo( new File( userDir, f.originalFilename))
            documentInstance.fileName = f.originalFilename
        }
        documentInstance.save()
        documentInstance.errors.each{
            println it
        }

        if(!documentInstance.hasErrors() && documentInstance.save()) {
            flash.message = "上传成功"
            redirect(action:show,id:documentInstance.id)
        }
        else {
            render(view:'create',model:[documentInstance:documentInstance])
        }

    }

引用

3.下载1

可以直接在gsp页面下载 gsp上的代码
 <g:each in="${documentInstanceList}" status="j" var="document">
            <tr>
           <td width="640" nowrap="nowrap" style="padding: 0 15px;border-bottom:1px #CCC dashed;">${fieldValue(bean:document, field:'title')}</td>
td width="64" height="40" class="table_link" style="border-bottom:1px #CCC dashed;">
<a href="${request.getContextPath()}/payload/${document.fileName}"  target="_blank">下载</a></td>
                  </tr>
</g:each>

下载2 
在controller里写下载action
    def download = {
            def documentInstance =  Document.get(params.id)
            def filename = documentInstance.fileName
           // println filename
            response.setHeader("Content-disposition", "attachment; filename=" + filename)
            response.contentType = ""

            def webRootDir = servletContext.getRealPath("/")
            def filepath = new File(webRootDir, "/upload/${filename}")
            //def filepath = "E:/founderweb/web-app/upload/${filename}"
           // println filepath
            def out = response.outputStream
            def inputStream = new FileInputStream(filepath)
            byte[] buffer = new byte[1024]
            int i = -1
            while ((i = inputStream.read(buffer)) != -1) {
                out.write(buffer, 0, i)
            }
            out.flush()
            out.close()
            inputStream.close()

    }
  页面gsp上代码
<g:link controller="document" action="download" id="${document.id}" target="_blank">下载</g:link>

引用

4.判断文件后缀名

int i = filename.LastIndexOf("."); //取得文件名中最后一个"."的索引 
                        string newext = filename.Substring(i); //获取文件扩展名 
                        if (newext != ".gif" && newext != ".jpg" && newext != ".jpeg" && newext != ".bmp" && newext != ".png")
                        {
                            Response.Write("文件格式不正确，请上传gif、jpg、jpeg、bmp及png的格式图片文件!"); 
                            Response.End();
                        } 

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5.判断文件上传大小

if(f.size>10240){
    }
  else{
}
   

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6.把上传文件名称以时间命名

def sdf = new SimpleDateFormat("yyyyMMddHHmmssS")//格式化时间输出
            def rname = sdf.format(new Date())//取得当前时间，Date()是java.util包里的，这作为真实名称
           // println rname
            def name = f.originalFilename//得到上传文件的原名称
             //println name
            int i = name.lastIndexOf(".")//原名称里倒数第一个"."在哪里
            def ext = name.substring(i+1)//取得后缀，及"."后面的字符
            name = rname+"."+ext//拼凑而成