4.从Request中获取文件数据

import java.io.File;import java.util.ArrayList;import java.util.List;import javax.servlet.http.HttpServletRequest;import org.apache.commons.fileupload.FileItem;import org.apache.commons.fileupload.FileUploadException;import org.apache.commons.fileupload.disk.DiskFileItemFactory;import org.apache.commons.fileupload.servlet.ServletFileUpload;/** * 工具类 -从HttpServletRequest中获取文件数据 *  */public class RequestUtil {    /**     * 从HttpServletRequest中获取所有的文件     *      * @param request     * @return FileItem对象列表     * @throws FileUploadException     */    public static List<FileItem> getFileItemList(HttpServletRequest request) throws FileUploadException {        List<FileItem> fileItemFromRequestList = getDataFromRequest(request);        if (fileItemFromRequestList != null && !fileItemFromRequestList.isEmpty()) {            List<FileItem> fileItemList = new ArrayList<>();            for (FileItem fileItem : fileItemFromRequestList) {                if (!fileItem.isFormField()) { // 文件                    fileItemList.add(fileItem);                }            }            return fileItemList;        }        return null;    }    /**     * 从request中获取FileItem对象列表     *      * @param request     * @return fileItemFromRequestList     * @throws FileUploadException     */    private static List<FileItem> getDataFromRequest(HttpServletRequest request) throws FileUploadException {        String tempPath = request.getServletContext().getRealPath("/temp");        File file = new File(tempPath);        DiskFileItemFactory factory = new DiskFileItemFactory();        factory.setSizeThreshold(1024 * 1024 * 1024);// 设置缓存大小        factory.setRepository(file);// 默认情况下 临时文件不会自动删除        ServletFileUpload servletFileUpload = new ServletFileUpload(factory);        List<FileItem> fileItemFromRequestList = servletFileUpload.parseRequest(request);        file.delete(); // 删除临时文件        return fileItemFromRequestList;    }}