SpringMVC 上传下载

下面介绍一下SpringMVC对文件的上传和下载，
注意：上传文件和下载文件不能使用Ajax请求，必须是form表单提交

上传

springMVC配置文件的配置：

 <!-- 上传文件解释器 -->     <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">     <property name="maxUploadSize" value="104857600" />     <property name="maxInMemorySize" value="4096" />     <property name="defaultEncoding" value="UTF-8"></property></bean>

Java后台

• contorller层：

    /**     * 上传文件     * @param file     * @param request     * @param session     * @return     */    @RequestMapping("upLoadFile")    @ResponseBody    public ResponseEntity upLoadFile(@RequestParam("addUploadFile") CommonsMultipartFile file,HttpServletRequest  request,HttpSession session){        Date date=new Date();        SimpleDateFormat sdfTime=new SimpleDateFormat("yyyy-MM-DD HH:mm:ss");       try{        List<Resource> resourceList=resourceService.findByResourceName(request.getParameter("addResourceName"));        if(resourceList.size()!=0){//判断用户名是否存在            return ResponseEntity.status(ResponseVoConstant.BADREQUEST).                            data(null).errorMessage(MessageUtil.getMessageValue("PROJECT_NAME_ALREADY_EXIST"));        }               String path="/PMS_Resource/"+request.getParameter("addProjectId");//文件保存路径        File newfile=new File(path,file.getOriginalFilename());         if (!newfile.exists()) {    //判断文件的路径是否存在               newfile.mkdirs();  //如果文件不存在  在目录中创建文件夹   这里要注意mkdir()和mkdirs()的区别                }                  file.transferTo(newfile);         Resource resource=new Resource();        resource.setResourceName(request.getParameter("addResourceName"));//资源名        resource.setResourceAddress(newfile.getPath());        resource.setPorjectId(Integer.parseInt(request.getParameter("addProjectId")));//项目ID        resource.setUploadUserId(Integer.parseInt(session.getAttribute("userId").toString()));        resource.setUploadTime(sdfTime.parse(sdfTime.format(date)));        resource.setResourceBrief(request.getParameter("addResourceBrief"));//资源简介        resourceService.save(resource);//保存资源信息        }catch (Exception e) {            return ResponseEntity.status(ResponseVoConstant.BADREQUEST).                    data(null).errorMessage(MessageUtil.getMessageValue("SAVE_FAIL"));        }        return ResponseEntity.status(ResponseVoConstant.OK).                data(null).errorMessage(MessageUtil.getMessageValue("UPLOAD_SUCCESS"));     }

此时文件就保存到这个路径下：

String path="/PMS_Resource/"+request.getParameter("addProjectId");//文件保存路径

前台界面代码

• HTML：

<form id="addResourceForm" method="post" class="form-horizontal">                        <div class="form-group">                            <label for="constantTypeName" class="col-sm-3 control-label">所属项目编号</label>                              <select class="form-control" id="addProjectId"                            name="addProjectId">                               </select>                            <!-- <div class="col-sm-9">                                <input type="text" class="form-control" id="addProjectId"                                    name="addProjectId" readonly>                            </div> -->                        </div>                        <div class="form-group">                            <label for="constantTypeName" class="col-sm-3 control-label">资源名称</label>                            <div class="col-sm-9">                                <input type="text" class="form-control" id="addResourceName"                                    name="addResourceName">                            </div>                        </div>                        <div class="form-group">                            <label for="constantTypeName" class="col-sm-3 control-label">资源上传</label>                            <div class="col-sm-9">                                <input type="file" class="form-control" id="addUploadFile" name="addUploadFile" onchange="checkResourceSize(this)">                            </div>                        </div>                        <div class="form-group">                            <label for="constantTypeName" class="col-sm-3 control-label">资源简介</label>                            <div class="col-sm-9">                                <textarea  class="form-control" id="addResourceBrief"                                    name="addResourceBrief"></textarea>                            </div>                        </div>                        <div class="form-group">                            <div class="col-sm-4 col-sm-offset-8" style="text-align: right">                                <button type="button" id="saveResourceBtn"                                    class="btn btn-primary" onclick="addResource()">保存</button>                                <button type="button" class="btn btn-default"                                    data-dismiss="modal">关闭</button>                            </div>                        </div>                        <div id="modalResourceTip"></div>                    </form>

• js代码：

function addResource() {    if($('#addResourceName').val()==''){            $("#modalResourceTip").append("<div id=\"resourceAlert\" class=\"alert alert-danger\"><a href=\"#\" class=\"close\" data-dismiss=\"alert\">&times;</a>资源名不能为空</div>");             setTimeout(function(){                   $("#resourceAlert").remove()                        },2000);             return false;          }    if( $('#addUploadFile').val().trim() ==""){            $("#modalResourceTip").append("<div id=\"resourceAlert\" class=\"alert alert-danger\"><a href=\"#\" class=\"close\" data-dismiss=\"alert\">&times;</a>请选择上传需要上传的资料</div>");             setTimeout(function(){                   $("#resourceAlert").remove()                        },2000);             return false;          }        if( $('#addResourceBrief').val().trim() ==""){            $("#modalResourceTip").append("<div id=\"resourceAlert\" class=\"alert alert-danger\"><a href=\"#\" class=\"close\" data-dismiss=\"alert\">&times;</a>请填写资源简介</div>");             setTimeout(function(){                   $("#resourceAlert").remove()                        },2000);             return false;          }    $("#addResourceForm").ajaxSubmit({          url: "../../resource/upLoadFile",          type: "post",          enctype: 'multipart/form-data',          // iframe: true,          dataType:'json',          success: function (data)          {              if(data.status=="2000"){                  $("#addResourceModal").modal('hide');//显示form模态框                  getData(1, 10);//重新加载数据              }else{                  $("#modalResourceTip").append("<div id=\"resourceAlert\" class=\"alert alert-danger\"><a href=\"#\" class=\"close\" data-dismiss=\"alert\">&times;</a>上传资源失败了，"+data.errorMessage+"</div>");                 setTimeout(function(){                    $("#resourceAlert").remove();                          },2000);              }          },          error: function (data)          {              $("#modalResourceTip").append("<div id=\"resourceAlert\" class=\"alert alert-danger\"><a href=\"#\" class=\"close\" data-dismiss=\"alert\">&times;</a>上传资源失败了，服务器出现了问题，请稍后重试</div>");             setTimeout(function(){                   $("#resourceAlert").remove();                       },2000);          }        })}/*** 检查文件大小* @param ele* @returns*/function checkResourceSize(ele){if((ele.files[0].size / 1024/1024).toFixed(2)>30){        $("#saveResourceBtn").attr("disabled","disabled");        $("#modalResourceTip").append("<div id=\"resourceAlert\" class=\"alert alert-danger\"><a href=\"#\" class=\"close\" data-dismiss=\"alert\">&times;</a>上传文件的大小不能超过30M</div>");         return false;      }else{        $("#saveResourceBtn").removeAttr("disabled");//将按钮可用           setTimeout(function(){               $("#resourceAlert").remove()                    },1000);    }}

这样上传文件就完成了！！

演示图片：

就上传到指定的路径下了

下载

Java后台：

/**     * 下载     * @param request     * @param response     * @return     * @throws Exception     */    @RequestMapping("downLoad")    @ResponseBody    public ResponseEntity downLoad(HttpServletRequest  request,HttpServletResponse response) throws Exception{           FileInputStream fis =null;           BufferedInputStream bis =null;        try {             //通过资源ID获取实体类          Resource retResource=resourceService.findResourceById(Integer.parseInt(request.getParameter("resourceId")));          File file = new File(retResource.getResourceAddress());          String path=retResource.getResourceAddress();//获取文件路径          String fileName=path.substring(path.lastIndexOf("\\")+1);//截取文件名          if(file.exists())          {           response.setContentType("application/octet-stream");           response.addHeader("Content-Disposition","attachment;filename="+new String(fileName.getBytes("utf-8"),"iso-8859-1"));           response.setHeader("Content-Length", String.valueOf(file.length()));           byte[] buffer = new byte[1024];            fis = new FileInputStream(file);            bis = new BufferedInputStream(fis);            OutputStream os =response.getOutputStream();            int i =bis.read(buffer);            while (i!=-1) {             os.write(buffer, 0, i);             i=bis.read(buffer);            }          }  else{              return ResponseEntity.status(ResponseVoConstant.BADREQUEST).                        data(null).errorMessage(MessageUtil.getMessageValue("DOWNLOAD_FIAL"));             }           } catch (Exception e) {              return ResponseEntity.status(ResponseVoConstant.BADREQUEST).                        data(null).errorMessage(MessageUtil.getMessageValue("DOWNLOAD_FIAL"));                 }finally {             bis.close();             fis.close();           }            return ResponseEntity.status(ResponseVoConstant.OK).                    data(null).errorMessage(MessageUtil.getMessageValue("DOWNLOAD_SUCCESS"));     }    /**     * 通过资源ID检查文件是否存在     * @param resource     * @param request     * @return     * @throws Exception      */    @RequestMapping("checkFileByResourceId")    @ResponseBody    public ResponseEntity checkFileByResourceId(@RequestBody Resource resource,HttpServletRequest request) throws Exception{        Resource retResource=resourceService.findResourceById(resource.getResourceId());        File file = new File(retResource.getResourceAddress());          if(file.exists()){//判断文件是否存在            return ResponseEntity.status(ResponseVoConstant.OK).                        data(null).errorMessage(MessageUtil.getMessageValue("FILE_EXIST"));            }          else {            return ResponseEntity.status(ResponseVoConstant.BADREQUEST).                        data(null).errorMessage(MessageUtil.getMessageValue("FILE_NO_EXIST"));          }    }

前台代码

• HTML

    <form id="updateResourceForm" method="post" class="form-horizontal">                        <div id="downloadResourceTip"></div>                        <div class="form-group">                            <div class="col-sm-4 col-sm-offset-8" style="text-align: right">                                <button type="button" id="downloadResourceBtn"                                    class="btn btn-primary" onclick="">下载</button>                                <button type="button" class="btn btn-default"                                    data-dismiss="modal">关闭</button>                            </div>                        </div>                    </form>

• js代码

/*** 下载资源* @param resourceId* @returns*/function downloadResource(resourceId) {  $("#downloadForm").remove();//移除之前下载时产生的form,防止冗余  var form=$("<form id='downloadForm'>");//定义一个form表单    form.attr("style","display:none");    form.attr("target","");    form.attr("method","post");    form.attr("action","../../resource/downLoad");    var inputResourceId=$("<input>");    inputResourceId.attr("type","text");    inputResourceId.attr("name","resourceId");    inputResourceId.attr("value",resourceId);    $("body").append(form);//将表单放置在web中    form.append(inputResourceId);    form.submit();//表单提交   }//确认资源能否下载function  checkResourceStatus(resourceId) {    $("#downloadResourceAlert").remove();    $("#downloadResourceBtn").removeAttr("disabled");//将按钮可用     $("#downloadResourceBtn").removeAttr("onclick");//移除下载事件    $.ajax({        url : '../../resource/checkFileByResourceId',         type: "POST",        contentType:'application/json',        data : JSON.stringify({            "resourceId":resourceId        }),        success : function(result) {            if(result.status=="2000"){                 $("#downloadResourceTip").append("<div id=\"downloadResourceAlert\" class=\"alert alert-success\"><a href=\"#\" class=\"close\" data-dismiss=\"alert\">&times;</a>资源正常，可以正常下载</div>");                 $("#downloadResourceBtn").attr("onclick","downloadResource("+resourceId+")");            }else{                 $("#downloadResourceTip").append("<div id=\"downloadResourceAlert\" class=\"alert alert-danger\"><a href=\"#\" class=\"close\" data-dismiss=\"alert\">&times;</a>"+result.errorMessage+"</div>");                  $("#downloadResourceBtn").attr("disabled","disabled");            }        },        error : function() {             $("#downloadResourceTip").append("<div id=\"downloadResourceAlert\" class=\"alert alert-danger\"><a href=\"#\" class=\"close\" data-dismiss=\"alert\">&times;</a>服务器出现了问题，暂时无法下载，请稍后重试</div>");                $("#downloadResourceBtn").attr("disabled","disabled");        }    });

这样下载就完成了，可以把刚刚上传的文件下载下来：

演示