springMvc3+extjs4的上传与下载

　　最近生活过的很充实,人一直在不停的忙碌着学习新东西。这是我最近遇到的问题，我找度娘n了很久，终于找到了解决方案!

　　前台代码:

 1 <script>   
 2  Ext.onReady(function() {
 3 
 4         Ext.create('Ext.form.Panel', {
 5             title : '文件上传',
 6             width : 400,
 7             bodyPadding : 10,
 8             frame : true,
 9             renderTo : document.body,
10             items : [ {
11                 xtype : 'filefield',
12                 name : '文件',
13                 fieldLabel : 'File',
14                 labelWidth : 50,
15                 msgTarget : 'side',
16                 allowBlank : false,
17                 anchor : '100%',
18                 buttonText : '请选择文件...'
19             } ],
20 
21             buttons : [ {
22                 text : '上传',
23                 handler : function() {
24                     var form = this.up('form').getForm();
25                     if (form.isValid()) {
26                         form.submit({
27                             url : '根路径/fileUploadDown/fileUpload',
28                             waitMsg : '正在上传文件中...',
29                             success : function(fp, o) {
30                                 Ext.Msg.alert('上传文件成功!');
31                             }
32                         });
33                     }
34                 }
35             } ]
36         });
37 
38     });
39 </script>

　　后台代码：

  1 /**
  2 *记录返回结果*/
  3  class ExtJSFormResult {
  4 
  5     private boolean success;
  6 
  7     public boolean isSuccess() {
  8         return success;
  9     }
 10 
 11     public void setSuccess(boolean success) {
 12 
 13     }
 14 
 15     public String toString() {
 16         return "{success:" + this.success + "}";
 17     }
 18 }
 19  
 20 
 21 class FileUploadBean {
 22 
 23         private CommonsMultipartFile file;
 24 
 25         public CommonsMultipartFile getFile() {
 26             return file;
 27         }
 28 
 29         public void setFile(CommonsMultipartFile file) {
 30             this.file = file;
 31         }
 32 }
 33 
 34 /**
 35  * 文件的上传与下载
 36  * @author Administrator
 37  *
 38  */
 39 @Controller
 40 @RequestMapping(value = "/fileUploadDown")
 41 public class FileUploadAndDownController {
 42    
 43     private static int countter=1; //定义一个计数器,用于上传文件的重命名
 44     
 45     @Autowired
 46     private ProAnnexDao<ProAnnex> proAnnextDao;
 47     
 48     
 49 
 50     public void setProAnnextDao(ProAnnexDao<ProAnnex> proAnnextDao) {
 51         this.proAnnextDao = proAnnextDao;
 52     }
 53 
 54     @RequestMapping(value="fileUpload",method = RequestMethod.POST)
 55     public @ResponseBody String create(RedirectAttributes redirectAttributes,FileUploadBean uploadItem, 
 56             BindingResult result,HttpSession session){
 57         //获取根路径
 58         String uploadFolderPath = session.getServletContext().getRealPath("/"); 
 59         ExtJSFormResult extjsFormResult = new ExtJSFormResult();
 60         try {
 61             
 62             if (result.hasErrors()) {
 63                 for (ObjectError error : result.getAllErrors()) {
 64                     System.err.println("Error: " + error.getCode() + " - "
 65                             + error.getDefaultMessage());
 66                 }
 67 
 68                 // 设置ExtJS返回 - error
 69                 extjsFormResult.setSuccess(false);
 70 
 71                 return extjsFormResult.toString();
 72             }
 73 
 74             MultipartFile file = uploadItem.getFile();
 75             String fileName = null;
 76             InputStream inputStream = null;
 77             OutputStream outputStream = null;
 78             if(file.getSize()>0){
 79                  System.out.println("File Size:::" + file.getSize());
 80                 if(file.getSize()>5242880){
 81                      System.out.println("File Size:::" + file.getSize());
 82                      extjsFormResult.setSuccess(false);
 83                     return "error";
 84                 }
 85                 
 86               inputStream = file.getInputStream();
 87         
 88               File newFile = new File(uploadFolderPath + "fileUpload/");
 89               //如果文件路径不存在就新建一个
 90               if(!newFile.exists()){
 91                  newFile.mkdirs();
 92               }
 93               //获取文件名
 94               String name=file.getOriginalFilename();
 95               //从数据库中查询存在此类文件名否
 96                Long count=proAnnextDao.isRepeatName(name);
 97                //如果存在一样的文件名,就进行从命名
 98                if (count>0) {
 99                    name=name.substring(0, name.lastIndexOf("."))+"("+(countter++)+")"+name.substring(name.lastIndexOf("."));
100                }
101                
102                fileName = uploadFolderPath + "fileUpload/" + name;
103                outputStream = new FileOutputStream(fileName); 
104                 int readBytes = 0;
105                 byte[] buffer = new byte[10000];
106                 while ((readBytes = inputStream.read(buffer, 0, 10000)) != -1) {
107                         outputStream.write(buffer, 0, readBytes);
108                 }
109                 
110                 outputStream.close();
111                 inputStream.close();
112               
113                 
114             }
115 
116             // 设置ExtJS返回 - sucsess
117             extjsFormResult.setSuccess(true);
118         } catch (Exception e) {
119             
120             e.printStackTrace();
121             // 设置ExtJS返回 - error
122         
123             extjsFormResult.setSuccess(false);
124         }
125         
126 
127         return extjsFormResult.toString();
128     }
129     
130 
131 }

springMvc.xml（此文件名可能跟项目的实际情况有区别）中的配置:

 1     
 2      <!-- 上传文件,限制大小的配置 -->
 3      <bean id="multipartResolver"
 4         class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
 5           <!--resolveLazily属性启用是为了推迟文件解析，以便在Upload中捕获文件大小异常-->
 6         <property name="resolveLazily" value="true"/>
 7         <property name="maxUploadSize" value="5242880" />
 8     </bean>
 9     
10     
11     <!-- 将无法mapping到Controller的path交给default servlet handler处理     -->    
12     <mvc:default-servlet-handler/><!-- 使用默认的servlet来响应静态文件 -->
13     <!-- 文件的上传与下载 -->
14     <mvc:view-controller path="/" view-name="redirect:/fileUploadDown"/>

　　以上的就是上传文件了。

　　那下载呢？

　下载比较简单,代码如下：

 1  @RequestMapping("/downloadFile")  
 2     public  void download(@Valid @ModelAttribute("downLoadName") String downLoadName,
 3             HttpServletResponse response,HttpSession session,BindingResult result,HttpServletRequest request) throws IOException {  
 4         
 5         response.setCharacterEncoding("UTF-8");
 6         request.setCharacterEncoding("UTF-8");
 7         //获取文件的路径
 8         String url=session.getServletContext().getRealPath("/")+"/fileUpload/"+downLoadName;
 9         System.out.println(url);
10         File file=new File(url);
11         
12         InputStream input = FileUtils.openInputStream(file);  
13         byte[] data = IOUtils.toByteArray(input);  
14  
15         //System.out.println("文件名:"+downLoadName);
16         response.reset();  
17       //设置响应的报头信息(中文问题解决办法)
18         response.setHeader("content-disposition","attachment;fileName="+URLEncoder.encode(downLoadName, "UTF-8"));
19         response.addHeader("Content-Length", "" + data.length);  
20         response.setContentType("application/octet-stream; charset=UTF-8");  
21        
22         IOUtils.write(data, response.getOutputStream());  
23         IOUtils.closeQuietly(input);  
24        
25     }

在界面上只要有一个连接地址：如:window.location.href="根路径/fileUploadDown/downfile/downLoadName="+name;这样就可以下载了.... 超连接的写法基本一样,这里就不多说了.