前文说到springMVC映射普通表单的开发方法，接下来讨论如何使用springmvc上传单个文件。
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springmvc对form表单的支持已经很成熟，仅仅两步：
/**
* @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);
}
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接下来验证结果是否正确：
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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：
/**
* @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);
}
}
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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 ！！
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源码下载：ssmFU.zip
原文：http://h-king.iteye.com/blog/2268976