我这里写了一个单个文件上传的例子，但不知道怎么弄成多个上传，而且可以判断文件是否重复。`<%@ page language="java" contentType="text/html; charset=UTF-8" {代码...} <!DOCTYPE html PUBLIC "-//W3C/...

javascript - 怎么把这个改成多文件上传并显示，而且文件不能重复？-PHP Chinese Network Q&A

我这里写了一个单个文件上传的例子，但不知道怎么弄成多个上传，而且可以判断文件是否重复。`<%@ page language="java" contentType="text/html; charset=UTF-8"

pageEncoding="UTF-8"%>

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>

<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Upload File</title>

<link rel="stylesheet" href="/css/Lumen.css"/>
<link rel="stylesheet" href="/css/iview.css"/>
<link rel="stylesheet" href="/css/index.css"/>

<script type="text/javascript" src="/js/jquery-2.1.0.min.js"></script>
<script type="text/javascript" src="/js/bootstrap.min.js"></script>
<script type="text/javascript" src="/js/vue.min.js"></script>
<script type="text/javascript" src="/js/iview.min.js"></script>
<script type="text/javascript" src="/js/jyajax.js"></script>

<script type="text/javascript">  
      
    j = 1;  
    $(document).ready(function(){  
          
        $("#btn_add2").click(function(){  
            document.getElementById("newUpload2").innerHTML+='<p id="p_'+j+'"><input  name="file_'+j+'" type="file"  /><input type="button" value="删除"  onclick="del_2('+j+')"/></p>';  
              j = j + 1;  
        });  
    });  
  
    
      
    function del_2(o){  
         document.getElementById("newUpload2").removeChild(document.getElementById("p_"+o));  
    }  
  
</script>

</head>
<body style="background-color: #7aba7b;">

 
<hr align="left" width="60%" color="#FF0000" size="3">  
<br>  
<br>  
<h1>springMVC包装类上传文件</h1>   
<form name="userForm2" action="/file/upload2" enctype="multipart/form-data" method="post">  
    <p id="newUpload2">  
        <input type="file" name="file">  
    </p>  
    <input type="button" id="btn_add2" value="增加一行"/>  
    <input type="submit" value="上传"/>  
</form>

<br/>

<input type="file" id="file"/>
<button type="button" class="btn btn-primary" @click="testUpload()">Click To Upload</button>

<script type="text/javascript">
var vue=new Vue({
    el:'body',
    data:{
        pager:{
            page:1,
            rows:10,
            totalPage:0,
            totalCount:0,
        },
    },
    methods:{
        initPage:function(){
            
        },
        /* 上传文件 */
        testUpload:function(){
            var file=document.getElementById("file");
            if(file.files.length<=0)return;
            var firstFile=file.files[0];
            var fd=new FormData();
            fd.append('avatar',firstFile);
            this.uploadAjax(fd);
        },
        uploadAjax:function(fd){
            var xhr=new XMLHttpRequest();
            xhr.open("POST","/file/uploadFile",true)
            xhr.onreadystatechange=function(){
              if (xhr.readyState==4 && xhr.status==200){
                  console.log(xhr.responseText);
                  alert("上传成功！");
              }
            };
            xhr.send(fd);
        },
        
    },
    ready:function(){
        this.initPage();
    },
    
});


</script>

</body>
</html>`

@Controller
@RequestMapping("file")
public class FileController {
    private final static String UPLOAD="E:/file/upload/";
    
    @RequestMapping("file")
    public String toFileJsp(){
        return "upLoadFile";
    }
    
    @RequestMapping("upload2")
    public String uploadTwo(HttpServletRequest request,HttpServletResponse response) throws IllegalStateException, IOException {
        //创建一个通用的多部分解析器
        CommonsMultipartResolver multipartResolver=new CommonsMultipartResolver(request.getSession().getServletContext());
        //判断 request 是否有文件上传,即多部分请求
        if(multipartResolver.isMultipart(request)){
            //转换成多部分request
            MultipartResolver resolver = new CommonsMultipartResolver(request.getSession().getServletContext());
            MultipartHttpServletRequest multiRequest = resolver.resolveMultipart(request);
            //MultipartHttpServletRequest multiRequest=(MultipartHttpServletRequest)request;
            //取得request中的所有文件名  
            Iterator<String> iterator=multiRequest.getFileNames();
            while(iterator.hasNext()){
                //记录上传过程起始时的时间，用来计算上传时间
                int startTime=(int)System.currentTimeMillis();
                //取得上传文件
                MultipartFile file=multiRequest.getFile(iterator.next());
                if(file!=null){
                    
                    //取得当前上传文件的文件名称
                    String fileName=file.getOriginalFilename();
                    //如果名称不为“”,说明该文件存在，否则说明该文件不存在 
                    if(fileName.trim() != ""){
                        System.out.println("文件名为："+fileName);
                        //定义上传路径 
                        String path="E:/file/"+fileName;
                        File localFile=new File(path);
                        file.transferTo(localFile);
                    }
                }
                //记录上传该文件后的时间
                int endTime=(int)System.currentTimeMillis();
                System.out.println("所用时间为："+(endTime-startTime));
            }
        }
        return "success";
    }
    
    @RequestMapping(value="uploadFile",method=RequestMethod.POST)
    @ResponseBody
    public Respon uploadFile(HttpServletRequest request){
        
        MultipartResolver resolver = new CommonsMultipartResolver(request.getSession().getServletContext());
        MultipartHttpServletRequest req = resolver.resolveMultipart(request);
        Respon respon=new Respon(Constant.CODE_ERROR,Constant.CODE_ERROR_STRING);
        MultipartFile file=req.getFile("avatar");
        if(file.getSize()>10*1024*1024){
            respon.setMsg("文件不得超过10M");
            return respon;
        }
        String fileName=file.getOriginalFilename();
        if(fileName.lastIndexOf(".")==-1){
            respon.setMsg("文件异常");
            return respon;
        }
        String ext=fileName.substring(fileName.lastIndexOf("."));
        List list=Arrays.asList(new String[]{".png",".jpg",".jpeg",".bmp"});
        if(!list.contains(ext.toLowerCase())){
            respon.setMsg("文件格式不允许");
            return respon;
        }
        //String base=request.getSession().getServletContext().getRealPath("/");
        SimpleDateFormat sdf=new SimpleDateFormat("yyyyMMdd");
        String newName=sdf.format(new Date())+"-"+UUID.randomUUID().toString()+ext;
        //String parentPath=base+UPLOAD;
        String parentPath=UPLOAD;
        File f=new File(parentPath);
        if(!f.exists()){
            f.mkdirs();
        }
        //String fileRealPath=base+UPLOAD+newName;
        String fileRealPath=UPLOAD+newName;
        File f2=new File(fileRealPath);
        if(f2.exists()){
            f2.delete();
        }
        try {
            file.transferTo(f2);
        } catch (IllegalStateException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        String webPath=UPLOAD+newName;
        respon.setCode(Constant.CODE_SUCCESS);
        respon.setMsg(Constant.CODE_SUCCESS_STRING);
        respon.setData(webPath);
        return respon;
    }
}