自定义，文件上传（common-fileupload）

支持jar:
commons-fileupload-1.3.jar、
commons-io-2.4.jar

/**
 * @title: FileDm.java
 * @develop: YanXiaojia R&D
 * @description: 文件上传实体。
 * @author: YanXiaojia
 * @version: 1.00
 */
public class FileDm {
	
	/**
	 * 文件名称
	 */
	private String fileName ;
	
	/**
	 * 文件类型
	 */
	private String fileType ;
	
	/**
	 * 允许上传的文件类型
	 */
	private String[] fileTypes ;
	
	/**
	 * 文件上传保存路径
	 */
	private String filePath ;
	
	/**
	 * <p>是否验证isMultiPart</p>
	 * 默认不使用, 即 isMultiPart = false.
	 */
	private Boolean isMultiPart = false;
	
	/**
	 * <p>是否使用虚拟目录</p>
	 * 默认不使用, 即 isVirdir = false.
	 */
	private Boolean isVirdir = false ;
	
	/**
	 * <p>缓冲区大小</p>
	 * 默认1M, 即(1024 * 1024 * 1).
	 */
	private Integer sizeThreshold = (1024 * 1024 * 1);
	
	/**
	 * <p>缓冲区目录</p>
	 */
	private File repository ;
	
	/**
	 * <p>是否限制上传文件大小</p>
	 * 默认不限制, 即isLimitSize = false.
	 */
	private Boolean isLimitSize = false;
	
	/**
	 * <p>上传文件最大限制</p>
	 * 默认10M, 即(1024 * 1024 * 10)
	 */
	private Integer sizeMax = (1024 * 1024 * 10);
	
	/**
	 * <p>文件编码</p>
	 * 默认UTF-8,即encoding = "UTF-8".
	 */
	private String encoding = "UTF-8";
	
	/**
	 * 处理文件后缀。
	 * @param fileName
	 */
	public void handleFileType(String fileName){
		this.setFileType(fileName.substring(fileName.lastIndexOf(".") + 1));
		
	}
	
	/**
	 * 是否被限制上传的文件类型
	 * @param fileType
	 * @return true:否	false:是
	 */
	public Boolean isAllowFileType(String fileType){
		for (int i = 0; i < this.getFileTypes().length; i++) {
			if(this.getFileTypes()[i].equals(fileType)){
				return true;
			}
		}
		return false;
	}
	
	/**
	 * 文件全名称（包含文件类型）
	 * @return 文件全名称
	 */
	public String getFileNameAll() {
		return this.getFileName() + "." + this.getFileType();
	}

	public String getFileName() {
		return fileName;
	}

	public void setFileName(String fileName) {
		this.fileName = fileName;
	}

	public String getFileType() {
		return fileType;
	}

	public void setFileType(String fileType) {
		this.fileType = fileType;
	}

	public String[] getFileTypes() {
		return fileTypes;
	}

	public void setFileTypes(String[] fileTypes) {
		this.fileTypes = fileTypes;
	}

	public String getFilePath() {
		return filePath;
	}

	public void setFilePath(String filePath) {
		this.filePath = filePath;
	}

	public Boolean getIsMultiPart() {
		return isMultiPart;
	}

	public void setIsMultiPart(Boolean isMultiPart) {
		this.isMultiPart = isMultiPart;
	}

	public Boolean getIsVirdir(){
		return isVirdir;
	}
	
	public void setIsVirdir(Boolean isVirdir){
		this.isVirdir = isVirdir;
	}

	public Integer getSizeThreshold() {
		if (!this.getIsVirdir()) {
			throw new IllegalStateException("isVirdir not set to true, sizeThreshold not operate.");
		}
		return sizeThreshold;
	}

	public void setSizeThreshold(Integer sizeThreshold) {
		this.sizeThreshold = sizeThreshold;
	}

	public File getRepository() {
		if (!this.getIsVirdir()) {
			throw new IllegalStateException("isVirdir not set to true, repository not operate.");
		}
		return repository;
	}

	public void setRepository(File repository) {
		this.repository = repository;
	}

	public Boolean getIsLimitSize() {
		return isLimitSize;
	}

	public void setIsLimitSize(Boolean isLimitSize) {
		this.isLimitSize = isLimitSize;
	}

	public Integer getSizeMax() {
		if (!this.getIsLimitSize()) {
			throw new IllegalStateException("isLimitSize not set to true, sizeMax not operate.");
		}
		return sizeMax;
	}

	public void setSizeMax(Integer sizeMax) {
		this.sizeMax = sizeMax;
	}

	public String getEncoding() {
		return encoding;
	}

	public void setEncoding(String encoding) {
		this.encoding = encoding;
	}
	
}

/**
 * @title: FileUpload.java
 * @develop: YanXiaojia R&D
 * @description: 文件上传工具。
 * @author: YanXiaojia
 * @version: 1.00
 */
public class FileUpload {

	/**
	 * 文件上传。
	 * @param request
	 * @throws Exception
	 */
	public static FileDm fileUpload(HttpServletRequest request, FileDm fm) throws Exception {
		// 创建基于磁盘文件项目的工厂
		DiskFileItemFactory factory = new DiskFileItemFactory();
		// 缓冲区目录
		factory.setRepository(fm.getRepository());
		// 缓冲区大小
		factory.setSizeThreshold(fm.getSizeThreshold());
		
		// 创建一个新文件上传
		ServletFileUpload upload = new ServletFileUpload(factory);
		// 设置文件编码
		upload.setHeaderEncoding(fm.getEncoding());
		// 设置文件上传大小
		upload.setSizeMax(fm.getSizeMax());
		
		// 检查输入请求是否为multiPart表单数据
		if (fm.getIsMultiPart()) {
			boolean isMultiPart = ServletFileUpload.isMultipartContent(request);
			if (isMultiPart == false) {
				throw new IllegalStateException("The enctype must be multipart/form-data.");
			}
		}
		// 解析请求
		List<FileItem> items = upload.parseRequest(request);
		// 上传项目过程
		Iterator<FileItem> iter = items.iterator();
		Boolean flag = true;
		while (iter.hasNext()) {
			FileItem item = iter.next();
			// 处理文件类型
			fm.handleFileType(item.getName());
			flag = fm.isAllowFileType(fm.getFileType());
			if (!flag) {
				throw new IllegalStateException("Upload file type is restricted.");
			}
			// 处理上传
			File field = new File(fm.getFileNameAll());
			String filePath = getFilePath(fm.getFilePath(),field.getName());
			fm.setFilePath(filePath);
			File file = new File(filePath);
			item.write(file);
		}
		return fm;
	}
	
	public static String getFilePath(String dir, String fileName) {
		String fileSeparator = System.getProperty("file.separator");
		if (!dir.endsWith(fileSeparator)) {
			dir += fileSeparator;
		}
		File file = new File(dir);
		if (!file.isDirectory()) { // 如果文件夹不存在就新建
			file.mkdirs();
		}
		return dir + fileName;

	}
}

/**
 * Servlet事例
 * Servlet implementation class Upload
 */
public class Upload extends HttpServlet {
	private static final long serialVersionUID = 1L;
       

	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		this.doPost(request, response);
	}

	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		FileUpload fileUpload = new FileUpload();
		fileUpload.setFileName(UUID.randomUUID().toString());
		// 允许上传的文件类型。
		fileUpload.setFileTypes(new String[]{"jpg","png","gif"});
		// 文件上传目录
		fileUpload.setFilePath("E:/project/apache.common.fileupload/");
		// 启用虚拟目录
		fileUpload.setIsVirdir(true);
		File ff = new File(request.getSession().getServletContext().getRealPath("/") + "temp/");
		fileUpload.setRepository(ff);
		// 限制文件上传大小
		fileUpload.setIsLimitSize(true);
		
		try {
			fileUpload=FileUploadUtil.fileUpload(request, fileUpload);
		} catch (Exception e) {
			e.printStackTrace();
		}
		request.setAttribute("msg","成功。");
		request.setAttribute("img", ff.toString().replace("\\", "/")+"/" +fileUpload.getFileNameAll());
		request.getRequestDispatcher("/succ.jsp").forward(request, response);
	}

}