使用Spring框架实现文件上传

使用Spring框架实现文件上传

在Java中实现文件的上传有多种方式,如smartUpload或是使用Strus2,本文与大家分享使用Spring框架中的MultipartFile类来实例文件的上传。

不啰嗦了,直接上干货。先是编写了一个实现文件上传的类FileUploadingUtil,此类中定义了两个对外公开的方法,upload和getFileMap。

前者需要传入一个Map参数,是用户提交的表单中的文件列表,最终返回值的也是一个Map类型对象,其键名为上传的文件名称,键值为文件在服务器上的存储路径;后者主要是用于测试用途,非主要功能,看官可以忽略此方法。

 

package com.emerson.cwms.utils;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Date;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Map.Entry;

import org.springframework.web.multipart.MultipartFile;

/**
 * 文件上传工具类
 * 
 * @author Chris Mao(Zibing)
 *
 */
public class FileUploadingUtil {

	/**
	 * 服务器上的保存路径,在使用到上传功能的Controller中对其进行赋值
	 */
	public static String FILEDIR = null;

	/**
	 * 上传多个文件,返回文件名称和服务器存储路径列表
	 * 
	 * @param files
	 * @return
	 * @throws IOException
	 */
	public static Map<String, String> upload(Map<String, MultipartFile> files) throws IOException {
		File file = new File(FILEDIR);
		if (!file.exists()) {
			file.mkdir();
		}

		Map<String, String> result = new HashMap<String, String>();
		Iterator<Entry<String, MultipartFile>> iter = files.entrySet().iterator();
		while (iter.hasNext()) {
			MultipartFile aFile = iter.next().getValue();
			if (aFile.getSize() != 0 && !"".equals(aFile.getName())) {
				result.put(aFile.getOriginalFilename(), uploadFile(aFile));
			}
		}
		return result;
	}

	/**
	 * 上传单个文件,并返回其在服务器中的存储路径
	 * 
	 * @param aFile
	 * @return
	 * @throws FileNotFoundException
	 * @throws IOException
	 */
	private static String uploadFile(MultipartFile aFile) throws IOException {
		String filePath = initFilePath(aFile.getOriginalFilename());
		try {
			write(aFile.getInputStream(), new FileOutputStream(filePath));
		} catch (FileNotFoundException e) {
			logger.error("上传的文件: " + aFile.getName() + " 不存在!!");
			e.printStackTrace();
		}
		return filePath;
	}

	/**
	 * 写入数据
	 * 
	 * @param in
	 * @param out
	 * @throws IOException
	 */
	private static void write(InputStream in, OutputStream out) throws IOException {
		try {
			byte[] buffer = new byte[1024];
			int bytesRead = -1;
			while ((bytesRead = in.read(buffer)) != -1) {
				out.write(buffer, 0, bytesRead);
			}
			out.flush();
		} finally {
			try {
				in.close();
				out.close();
			} catch (IOException ex) {
			}
		}
	}

	/**
	 * 遍历服务器目录,列举出目录中的所有文件(含子目录)
	 * @return
	 */
	public static Map<String, String> getFileMap() {
		logger.info(FileUploadingUtil.FILEDIR);
		Map<String, String> map = new HashMap<String, String>();
		File[] files = new File(FileUploadingUtil.FILEDIR).listFiles();
		if (files != null) {
			for (File file : files) {
				if (file.isDirectory()) {
					File[] files2 = file.listFiles();
					if (files2 != null) {
						for (File file2 : files2) {
							String name = file2.getName();
							logger.info(file2.getParentFile().getAbsolutePath());
							logger.info(file2.getAbsolutePath());
							map.put(file2.getParentFile().getName() + "/" + name,
									name.substring(name.lastIndexOf("_") + 1));
						}
					}
				}
			}
		}
		return map;
	}

	/**
	 * 返回文件存储路径,为防止重名文件被覆盖,在文件名称中增加了随机数
	 * @param name
	 * @return
	 */
	private static String initFilePath(String name) {
		String dir = getFileDir(name) + "";
		File file = new File(FILEDIR + dir);
		if (!file.exists()) {
			file.mkdir();
		}
		Long num = new Date().getTime();
		Double d = Math.random() * num;
		return (file.getPath() + "/" + num + d.longValue() + "_" + name).replaceAll(" ", "-");
	}

	/**
	 * 
	 * @param name
	 * @return
	 */
	private static int getFileDir(String name) {
		return name.hashCode() & 0xf;
	}
}


Controller代码,使用上述定义的FileUploadingUtil类实现文件上传之功能。

 

 

package com.emerson.cwms.web;

import java.io.IOException;
import java.util.Iterator;
import java.util.Map;
import java.util.Map.Entry;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.multipart.MultipartHttpServletRequest;

import com.emerson.cwms.utils.FileUploadingUtil;

/**
 * 文件上传控制器
 * 
 * @author Chris Mao(Zibing)
 *
 */
@Controller
@RequestMapping(value = "/files")
public class FileController {
	
	@RequestMapping(value = "/", method = RequestMethod.GET)
	public String list(HttpServletRequest request, HttpServletResponse response, Model model) {
		iniFileDir(request);
		
		System.out.println(request.getAttribute("files"));
		model.addAttribute("files", FileUploadingUtil.getFileMap());
		return "files/list";
	}
	
	@RequestMapping(value = "/upload", method = RequestMethod.POST)
	public String doUpload(HttpServletRequest request) {
		iniFileDir(request);
		
		try {
			MultipartHttpServletRequest mRequest = (MultipartHttpServletRequest) request;
			Map<String, String> uploadedFiles = FileUploadingUtil.upload(mRequest.getFileMap());

			Iterator<Entry<String, String>> iter = uploadedFiles.entrySet().iterator();
			while (iter.hasNext()) {
				Entry<String, String> each = iter.next();
				System.out.print("Uploaded File Name = " + each.getKey());
				System.out.println(", Saved Path in Server = " + each.getValue());
			}
		} catch (Exception e) {
			e.printStackTrace();
		}
		return "redirect:/files/";
	}

	private void iniFileDir(HttpServletRequest request) {
		FileUploadingUtil.FILEDIR = request.getSession().getServletContext().getRealPath("/") + "files/";
		if (FileUploadingUtil.FILEDIR == null) {
			FileUploadingUtil.FILEDIR = request.getSession().getServletContext().getRealPath("/") + "files/";
		}
	}
}


注意事项:一定要在pom.xml文件中添加对commons-fileupload的依赖引用,否则代码在运行时会提示找不到FileItemFactory类的错误。

 

依赖引用如下。

 

<dependency>
	<groupId>commons-fileupload</groupId>
	<artifactId>commons-fileupload</artifactId>
	<version>1.3.1</version>
</dependency>



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