ssm文件上传下载比较详细的案例

背景：ssm框架

接下来，我会介绍单文件上传，下载，多文件的上传，下载，使用ajax进行文件的上传下载，和普通的表单提交的文件上传下载。

只要做项目，总是少不了文件的操作，好了废话不多说，直接上代码！

前提：需要在springmvc的配置文件里面加一个文件解析器，这个必须要有！！！

  <!-- 定义文件解释器 -->
     <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
         <!-- 设置默认编码 -->
         <property name="defaultEncoding" value="utf-8"></property>
         <!-- 上传图片最大大小5M-->
         <property name="maxUploadSize" value="5242440"></property>
     </bean>  

随便提下：需要的jar包，我项目使用的maven构建，直接添加的依赖，jar包是下面两个：

　　commons-fileupload-1.3.2.jar
　　commons-io-2.2.jar

一、单文件的文件上传、下载

　　上传：前台

<form  id ="form2" action="load/upload2" enctype="multipart/form-data" method="post">
    <input type = "file" name= 'file' />
    <input type="text" name="name" value="dzf"/>
    <input type="button" id = "button2" value="ajax上传" onclick="fileupload2()">
    <input type ="submit" value="直接上传">
</form> 

 function fileupload2(){
     var formData = new FormData($("#form2")[0]);
     $.ajax({
             url:'load/upload2',
             type:'post',
             data:formData,
             //必须false才会自动加上正确的Content-Type
             contentType: false,
             //必须false才会避开jQuery对 formdata 的默认处理
             //XMLHttpRequest会对 formdata 进行正确的处理
             processData: false,
             success:function(data){
                 alert(data);
             },
             error:function(data){
                 alert(data);
                 alert("后台发生异常");
             },
             cache:false,
             async:true
         });
 }

后台：

 /**
      * 单个文件上传
      * @param request
      * @return
      */
     @RequestMapping(value="/upload2",produces="text/html;charset=utf-8")
     @ResponseBody
     private String upload2(@RequestParam("file")CommonsMultipartFile partFile,HttpServletRequest request) {
         try {
             String path = request.getServletContext().getRealPath("/upload");
             String name = request.getParameter("name");
             log.info("其他的参数{}",name);
             log.info("upload2---------------start---------------------");
             log.info("这个临时文件的路径是[{}]", path);
             String filename = partFile.getOriginalFilename();
             log.info("文件的名字：{}",filename);
             File file = new File(path+"/"+filename);
             InputStream inputStream = partFile.getInputStream();
             FileUtils.copyInputStreamToFile(inputStream, file);
             if(inputStream!=null){
                 inputStream.close();
             }
             return "文件上传成功！";
         } catch (Exception e) {
             e.printStackTrace();
             return "文件上传失败！";
         }
     }

下载：前台

 <form action="load/down1" name="form3" id = "form3" method="post">
     <input type = "submit" value="普通文件下载">
 </form>

后台：

 /**
      * 文件下载
      * 单个文件下载
      * @param request
      * @return
      * @throws IOException
      */
     @RequestMapping("/down1")
     private void down(HttpServletRequest request,HttpServletResponse response) throws IOException {
         String path = request.getServletContext().getRealPath("/upload");
         File file = new File(path);
         File[] files = file.listFiles();
         String name = files[0].getName();//随机获取一个文件，实际中按需编写代码
         System.out.println("文件的名字："+name);
         response.addHeader("content-disposition", "attachment;filename="+name);
         FileUtils.copyFile(files[0], response.getOutputStream());
     }

二、多文件的上传和下载

上传-前台：

 <form  id ="form5" action="load/upload3" enctype="multipart/form-data" method="post">
     <input type = "file" name= 'file' />
     <input type = "file" name= 'file' />
     <input type = "file" name= 'file' />
     <input type="text" name="name" value="dzf"/>
     <input type="button" id = "button2" value="多文件ajax上传" onclick="fileupload3()">
     <input type ="submit" value="多文件直接上传">
 </form> 

 function fileupload3(){
     var formData = new FormData($("#form5")[0]);
         $.ajax({
                 url:'load/upload3',
                 type:'post',
                 data:formData,
                 //必须false才会自动加上正确的Content-Type
                 contentType: false,
                 //必须false才会避开jQuery对 formdata 的默认处理
                 //XMLHttpRequest会对 formdata 进行正确的处理
                 processData: false,
                 success:function(data){
                     alert(data);
                 },
                 error:function(data){
                     alert(data);
                     alert("后台发生异常");
                 },
                 cache:false,
                 async:true
             });
 }

上传-后台：

 /**
      * 多个文件上载
      * @param request
      * @return
      */
     @RequestMapping(value="/upload3",produces="text/html;charset=utf-8")
     @ResponseBody
     private String upload3(@RequestParam("file")CommonsMultipartFile[] partFiles,HttpServletRequest request) {
         InputStream inputStream = null;
         try {
             String path = request.getServletContext().getRealPath("/upload");
             String name = request.getParameter("name");
             log.info("其他的参数{}",name);
             log.info("upload2---------------start---------------------");
             log.info("这个临时文件的路径是[{}]", path);
             for (int i = 0; i < partFiles.length; i++) {
                 String filename = partFiles[i].getOriginalFilename();
                 log.info("文件的名字：{}",filename);
                 File file = new File(path+"/"+filename);
                 inputStream = partFiles[i].getInputStream();
                 FileUtils.copyInputStreamToFile(inputStream, file);
             }
             if(inputStream!=null){
                 inputStream.close();
             }
             return "文件上传成功！";
         } catch (Exception e) {
             e.printStackTrace();
             return "文件上传失败！";
         }
     }

一次性下载多个文件，我们需要把文件放到一个压缩包里去

下载-前台：

 <form action="load/down2" name="form4" id = "form4" method="post">
     <input type = "submit" value="压缩文件下载">
 </form>

下载-后台：

 /**
      * 文件下载，一下次下载多个文件
      * 思路：先将多个文件压缩到一个压缩包里去，然后传到前台
      * @param request
      * @return
      * @throws IOException
      */
     @RequestMapping("/down2")
     private void down2(HttpServletRequest request,HttpServletResponse response) throws IOException {
         String path = request.getServletContext().getRealPath("/upload");
         File file = new File(path);
         File[] files = file.listFiles();
         File zipFile =new File("test.zip");
         if(!zipFile.exists()){
             zipFile.createNewFile();
         }
         String zipName = zipFile.getName();
         log.info("压缩文件的名字：{}",zipName);
         response.addHeader("Content-Disposition", "attachment;filename="+zipName);
         //定义输出类型
 //        response.setContentType("application/zip");
         ZipOutputStream zip = new ZipOutputStream(new FileOutputStream(zipFile));
         BufferedInputStream in  =null;
         log.info("文件的个数{}",files.length);
         for(int i = 0;i<files.length;i++){
             String name = files[i].getName();
             System.out.println("文件的名字："+name);
             ZipEntry zipEntry = new ZipEntry(name);
             zip.putNextEntry(zipEntry);
             in = new BufferedInputStream(new FileInputStream(files[i]));
             int len = 0;
             byte [] btyes = new byte[1024*4];
             while((len=in.read(btyes))!=-1){
                 zip.write(btyes, 0, len);
             }
         }
         zip.flush();
         zip.close();
         in.close();
         FileUtils.copyFile(zipFile, response.getOutputStream());
         if(zipFile.exists()){
             if(zipFile.delete()){
                 log.info("压缩包删成功！！");
             }else{
                 log.info("压缩包产出失败！！");
             }

         }
     }

到此，文件的上传、下载实例代码已经全部结束！