分享一个操作文件/文件夹的工具类，实现给客户端导出文件

import org.apache.commons.io.IOUtils;

import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.File;
import java.io.FileInputStream;
import java.util.ArrayList;
import java.util.List;

public class FileOperateUtil {

	//删除文件夹
	//param folderPath 文件夹完整绝对路径

	     public static void delFolder(String folderPath) {
	     try {
	        delAllFile(folderPath); //删除完里面所有内容
	        String filePath = folderPath;
	        filePath = filePath.toString();
	        java.io.File myFilePath = new java.io.File(filePath);
	        myFilePath.delete(); //删除空文件夹
	     } catch (Exception e) {
	       e.printStackTrace(); 
	     }
	}

	//删除指定文件夹下所有文件
	//param path 文件夹完整绝对路径
	   public static boolean delAllFile(String path) {
	       boolean flag = false;
	       File file = new File(path);
	       if (!file.exists()) {
	         return flag;
	       }
	       if (!file.isDirectory()) {
	         return flag;
	       }
	       String[] tempList = file.list();
	       File temp = null;
	       for (int i = 0; i < tempList.length; i++) {
	          if (path.endsWith(File.separator)) {
	             temp = new File(path + tempList[i]);
	          } else {
	              temp = new File(path + File.separator + tempList[i]);
	          }
	          if (temp.isFile()) {
	             temp.delete();
	          }
	          if (temp.isDirectory()) {
	             delAllFile(path + "/" + tempList[i]);//先删除文件夹里面的文件
	             delFolder(path + "/" + tempList[i]);//再删除空文件夹
	             flag = true;
	          }
	       }
	       return flag;
	     }
	   
	   
	   /**
	    * 遍历文件夹中的所有文件放入list集合
	    * 
	    * 
	    */
	   public static List<File> traverFolder(String path) {
		   
		   ArrayList<File> arrayList = new ArrayList<File>();
		   
	        File file = new File(path);
	        if (file.exists()) {
	            File[] files = file.listFiles();
	            if (files.length == 0) {
	                System.out.println("文件夹是空的!");
	                return null;
	            } else {
	                for (File file2 : files) {
	                    if (file2.isDirectory()) {
	                        System.out.println("文件夹:" + file2.getAbsolutePath());
	                        traverFolder(file2.getAbsolutePath());
	                    } else {
	                    	arrayList.add(new File(file2.getAbsolutePath()));
	                    }
	                }
	                return arrayList;
	            }
	        } else {
	            System.out.println("文件不存在!");
	            return null;
	        }
	    }

	/**
	 * 给客户端导出文件
	 * @param path
	 * @param fileName
	 * @param request
	 * @param response
	 */
	public static void fileOutput(String path, String fileName, HttpServletRequest request, HttpServletResponse response){
		try{
			//根据文件名获取 MIME 类型
			String contentType = request.getServletContext().getMimeType(path);
			fileName = new String(fileName.getBytes("UTF-8"),"iso-8859-1");
			String contentDisposition = "attachment;filename="+fileName;
			// 输入流
			FileInputStream input = new FileInputStream(path);
			// 设置头
			response.setHeader("Content-Type",contentType);
			response.setHeader("Content-Disposition",contentDisposition);
			// 获取绑定了客户端的流
			ServletOutputStream output = response.getOutputStream();
			// 把输入流中的数据写入到输出流中
			IOUtils.copy(input,output);
			input.close();
		}catch (Exception e){
			e.printStackTrace();
		}
	}

}