springMVC之单文件上传

springmvc对form表单的支持已经很成熟，仅仅两步：

1. 配置支持文件上传的bean：org.springframework.web.multipart.commons.CommonsMultipartResolver
   
     同时设置文件编码、单次提交表单上传文件最大字节数、以及写文件时使用的缓冲区大小
2. 开发处理：handler[org.hy.ssm.web.controller.FormController.uploadOne(MultipartFile)]
    

   /**
    * @Title: uploadOne
    * @Description: 单文件上传
    * @param file
    * @return ModelMap
    */
   @RequestMapping("/uploadOne")
   @ResponseBody
   public ModelMap uploadOne(MultipartFile file) {
       final String UPLOAD_DIR = "/upload/";
       final String KEY_OF_ORIGINAL_FILE_NAME = "origFileName";
       final String KEY_OF_FILE_URL = "fileUrl";
       final String KEY_OF_FILE_SUFFIX = "fileSuffix";
   
       boolean flag = false;
       String message = null;
       Map<String, String> data = Maps.newHashMap();
   
       // 原文件名(通常用于下载展示)
       String originalFilename = file.getOriginalFilename();
       data.put(KEY_OF_ORIGINAL_FILE_NAME, originalFilename);
   
       // 文件类型(后缀)
       String suffix = FileUtil.getSuffix(originalFilename);
       data.put(KEY_OF_FILE_SUFFIX, suffix);
   
       // 目标文件名(通常情况需要重命名, 防止同名文件覆盖)
       String fileName = String.valueOf(System.currentTimeMillis()) + suffix;
       String fileUrl = (UPLOAD_DIR + fileName);
       data.put(KEY_OF_FILE_URL, fileUrl);
   
       try {
           File dest = WebUtil.getFile(fileUrl);
           file.transferTo(dest);
           flag = true;
       } catch (Exception e) {
           flag = false;
           message = "";
           LOGGER.warn(message + " : " + e.getMessage(), e);
       }
   
       return WebUtil.getModelMap(flag, data, message);
   }

    

接下来验证结果是否正确：

 

• 正常验证
  
   
  
   
• 非法验证，文件大小超出。当前测试数据70+MB

  org.springframework.web.multipart.MaxUploadSizeExceededException: Maximum upload size of 32505856 bytes exceeded; nested exception is org.apache.commons.fileupload.FileUploadBase$SizeLimitExceededException: the request was rejected because its size (79882924) exceeds the configured maximum (32505856)
      at org.springframework.web.multipart.commons.CommonsMultipartResolver.parseRequest(CommonsMultipartResolver.java:160)
      at org.springframework.web.multipart.commons.CommonsMultipartResolver.resolveMultipart(CommonsMultipartResolver.java:139)
      at org.springframework.web.servlet.DispatcherServlet.checkMultipart(DispatcherServlet.java:1020)
      at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:883)
      at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:852)
      at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:882)
      at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:789)
      at javax.servlet.http.HttpServlet.service(HttpServlet.java:646)
      at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
      at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
      at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
      at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
      at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
      at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
      at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
      at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
      at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:504)
      at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:170)
      at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
      at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950)
      at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
      at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:421)
      at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1074)
      at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:611)
      at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:316)
      at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
      at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
      at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
      at java.lang.Thread.run(Thread.java:722)
  Caused by: org.apache.commons.fileupload.FileUploadBase$SizeLimitExceededException: the request was rejected because its size (79882924) exceeds the configured maximum (32505856)
      at org.apache.commons.fileupload.FileUploadBase$FileItemIteratorImpl.<init>(FileUploadBase.java:937)
      at org.apache.commons.fileupload.FileUploadBase.getItemIterator(FileUploadBase.java:331)
      at org.apache.commons.fileupload.FileUploadBase.parseRequest(FileUploadBase.java:351)
      at org.apache.commons.fileupload.servlet.ServletFileUpload.parseRequest(ServletFileUpload.java:126)
      at org.springframework.web.multipart.commons.CommonsMultipartResolver.parseRequest(CommonsMultipartResolver.java:156)
      ... 28 more

   由错误也可定位出，#multipartResolver.maxUploadSize 是用来定位单次表单提交时，文件的限定大小

到此，单文件上传已经搞定。是不是很简单呢？当然了还有稍微原始的方法，通过 org.apache.commons.fileupload.servlet.ServletFileUpload 也能实现文件上传的功能，在此不做详解。大致步骤如下：

1. 获取工厂 DiskFileItemFactory
2. 通过工厂获取上传组件 ServletFileUpload
3. 解析请求获取表单项
4. 判断表单项类型
5. 解析表单项

/**
 * @Title: uploadByFileUpload
 * @Description: 使用Commons.FileUpload上传文件
 */
@RequestMapping("/uploadByFileUpload")
public void uploadByFileUpload() {
    final String UPLOAD_DIR = "upload/";
    final String basePath = WebUtil.getBaseFilPath();

    HttpServletRequest request = WebUtil.getRequest();
    try {
        // 防止中文名乱码
        request.setCharacterEncoding("utf-8");

        // 1. 获取工厂 DiskFileItemFactory
        DiskFileItemFactory fileItemFactory = new DiskFileItemFactory();
        // 缓存区目录
        fileItemFactory.setRepository(new File(basePath + "tmp/"));
        // 缓存区大小
        fileItemFactory.setSizeThreshold(1024 * 6);

        // 2. 通过工厂获取上传组件 ServletFileUpload
        ServletFileUpload servletFileUpload = new ServletFileUpload(fileItemFactory);
        // 设置文件的大小为2M
        servletFileUpload.setSizeMax(1024 * 1024 * 2);
        // 防止中文乱码(文件名)
        servletFileUpload.setHeaderEncoding("UTF-8");

        // 3. 解析请求获取表单项
        @SuppressWarnings("unchecked")
        List<FileItem> items = servletFileUpload.parseRequest(request);

        // 4. 判断表单项类型
        for (FileItem item : items) {

            // 5. 解析表单项
            // 表单项名称
            String fieldName = item.getFieldName();
            if (item.isFormField()) {
                // 普通表单项处理
                String name = fieldName;
                String value = item.getString("UTF-8");
                System.out.println(name + ":" + value);

            } else {
                // 文件表单项
                // 获取文件名
                String originalFileName = item.getName();
                String suffix = FileUtil.getSuffix(originalFileName);
                String newFileName = String.valueOf(System.currentTimeMillis());

                // 写入文件
                String fileName = File.separator + newFileName + suffix;
                File newFile = FileUtil.createQuietly(basePath + UPLOAD_DIR + fileName);
                item.write(newFile);
                item.delete();
            }
        }

    } catch (Exception e) {
        LOGGER.warn(e.getMessage(), e);
    }
}

注意：如果使用上面的方式获取上传文件，需要停止 springmvc 的文件解析机制，否则将不能获取数据 ！！

 

源码下载：ssmFU.zip

• ssmFU.zip (130.6 KB)