详解SpringMVC使用MultipartFile实现文件的上传

如果需要实现跨服务器上传文件，就是将我们本地的文件上传到资源服务器上，比较好的办法就是通过ftp上传。这里是结合SpringMVC+ftp的形式上传的。我们需要先懂得如何配置springMVC，然后在配置ftp，最后再结合MultipartFile上传文件。

springMVC上传需要几个关键jar包，spring以及关联包可以自己配置，这里主要说明关键的jar包

1：spring-web-3.2.9.RELEASE.jar (spring的关键jar包，版本可以自己选择)

2：commons-io-2.2.jar (项目中用来处理IO的一些工具类包)

配置文件

SpringMVC是用MultipartFile来进行文件上传的，因此我们先要配置MultipartResolver，用于处理表单中的file

<!-- 上传文件解释器 -->
  <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
    <property name="defaultEncoding" value="utf-8" />
    <property name="maxUploadSize" value="10485760" />
    <property name="maxInMemorySize" value="4096" />
    <property name="resolveLazily" value="true" />
  </bean> 

其中属性详解：

defaultEncoding配置请求的编码格式，默认为iso-8859-1

maxUploadSize配置文件的最大单位，单位为字节

maxInMemorySize配置上传文件的缓存 ，单位为字节

resolveLazily属性启用是为了推迟文件解析，以便在UploadAction 中捕获文件大小异常

页面配置

在页面的form中加上enctype="multipart/form-data"

<form id="" name="" method="post" action="" enctype="multipart/form-data">  

表单标签中设置enctype="multipart/form-data"来确保匿名上载文件的正确编码。

是设置表单的MIME编码。默认情况，这个编码格式是application/x-www-form-urlencoded，不能用于文件上传；只有使用了multipart/form-data，才能完整的传递文件数据，进行下面的操作。enctype="multipart/form-data"是上传二进制数据。form里面的input的值以2进制的方式传过去，所以request就得不到值了。

编写上传控制类

编写一个上传方法，这里没有返回结果，需要跳转页面或者返回其他值可以将void改为String、Map<String,Object>等值，再return返回结果。

    /**
 * 上传
 * @param request
 * @return
 */
@ResponseBody
@RequestMapping(value = "/upload", method = {RequestMethod.GET, RequestMethod.POST})
public void upload(HttpServletRequest request) {
  MultipartHttpServletRequest multipartRequest=(MultipartHttpServletRequest)request;
  MultipartFile file = multipartRequest.getFile("file");//file是页面input的name名
  String basePath = "文件路径"
  try {
    MultipartResolver resolver = new CommonsMultipartResolver(request.getSession().getServletContext());
      if (resolver.isMultipart(request)) {
      String fileStoredPath = "文件夹路径";
      //随机生成文件名
      String randomName = StringUtil.getRandomFileName();
      String uploadFileName = file.getOriginalFilename();
      if (StringUtils.isNotBlank(uploadFileName)) {
        //截取文件格式名
        String suffix = uploadFileName.substring(uploadFileName.indexOf("."));
        //重新拼装文件名
        String newFileName = randomName + suffix;
        String savePath = basePath + "/" + newFileName;
        File saveFile = new File(savePath);
        File parentFile = saveFile.getParentFile();
        if (saveFile.exists()) {
          saveFile.delete();
        } else {
          if (!parentFile.exists()) {
            parentFile.mkdirs();
          }
        }
        //复制文件到指定路径
        FileUtils.copyInputStreamToFile(file.getInputStream(), saveFile);
        //上传文件到服务器
        FTPClientUtil.upload(saveFile, fileStoredPath);
      }
    }
  } catch (Exception e) {
    e.printStackTrace();
  }
}

FTP客户端上传工具

package com.yuanding.common.util; 

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.SocketException;
import java.util.HashMap;
import java.util.Map;
import java.util.Properties; 

import org.apache.commons.lang.StringUtils;
import org.apache.commons.net.ftp.FTP;
import org.apache.commons.net.ftp.FTPClient;
import org.apache.commons.net.ftp.FTPReply;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory; 

/**
 * FTP客户端工具
 */
public class FTPClientUtil { 

  /**
   * 日志
   */
  private static final Logger LOGGER = LoggerFactory.getLogger(FTPClientUtil.class); 

  /**
   * FTP server configuration--IP key,value is type of String
   */
  public static final String SERVER_IP = "SERVER_IP"; 

  /**
   * FTP server configuration--Port key,value is type of Integer
   */
  public static final String SERVER_PORT = "SERVER_PORT"; 

  /**
   * FTP server configuration--ANONYMOUS Log in key, value is type of Boolean
   */
  public static final String IS_ANONYMOUS = "IS_ANONYMOUS"; 

  /**
   * user name of anonymous log in
   */
  public static final String ANONYMOUS_USER_NAME = "anonymous"; 

  /**
   * password of anonymous log in
   */
  public static final String ANONYMOUS_PASSWORD = ""; 

  /**
   * FTP server configuration--log in user name, value is type of String
   */
  public static final String USER_NAME = "USER_NAME"; 

  /**
   * FTP server configuration--log in password, value is type of String
   */
  public static final String PASSWORD = "PASSWORD"; 

  /**
   * FTP server configuration--PASV key, value is type of Boolean
   */
  public static final String IS_PASV = "IS_PASV"; 

  /**
   * FTP server configuration--working directory key, value is type of String While logging in, the current directory
   * is the user's home directory, the workingDirectory must be set based on it. Besides, the workingDirectory must
   * exist, it can not be created automatically. If not exist, file will be uploaded in the user's home directory. If
   * not assigned, "/" is used.
   */
  public static final String WORKING_DIRECTORY = "WORKING_DIRECTORY"; 

  public static Map<String, Object> serverCfg = new HashMap<String, Object>(); 

  static Properties prop; 

  static{
    LOGGER.info("开始加载ftp.properties文件!");
    prop = new Properties();
    try {
      InputStream fps = FTPClientUtil.class.getResourceAsStream("/ftp.properties");
      prop.load(fps);
      fps.close();
    } catch (Exception e) {
      LOGGER.error("读取ftp.properties文件异常!",e);
    }
    serverCfg.put(FTPClientUtil.SERVER_IP, values("SERVER_IP"));
    serverCfg.put(FTPClientUtil.SERVER_PORT, Integer.parseInt(values("SERVER_PORT")));
    serverCfg.put(FTPClientUtil.USER_NAME, values("USER_NAME"));
    serverCfg.put(FTPClientUtil.PASSWORD, values("PASSWORD"));
    LOGGER.info(String.valueOf(serverCfg));
  } 

  /**
   * Upload a file to FTP server.
   *
   * @param serverCfg : FTP server configuration
   * @param filePathToUpload : path of the file to upload
   * @param fileStoredName : the name to give the remote stored file, null, "" and other blank word will be replaced
   *      by the file name to upload
   * @throws IOException
   * @throws SocketException
   */
  public static final void upload(Map<String, Object> serverCfg, String filePathToUpload, String fileStoredName)
      throws SocketException, IOException {
    upload(serverCfg, new File(filePathToUpload), fileStoredName);
  } 

  /**
   * Upload a file to FTP server.
   *
   * @param serverCfg : FTP server configuration
   * @param fileToUpload : file to upload
   * @param fileStoredName : the name to give the remote stored file, null, "" and other blank word will be replaced
   *      by the file name to upload
   * @throws IOException
   * @throws SocketException
   */
  public static final void upload(Map<String, Object> serverCfg, File fileToUpload, String fileStoredName)
      throws SocketException, IOException {
    if (!fileToUpload.exists()) {
      throw new IllegalArgumentException("File to upload does not exists：" + fileToUpload.getAbsolutePath 

());
    }
    if (!fileToUpload.isFile()) {
      throw new IllegalArgumentException("File to upload is not a file:" + fileToUpload.getAbsolutePath());
    }
    if (StringUtils.isBlank((String) serverCfg.get(SERVER_IP))) {
      throw new IllegalArgumentException("SERVER_IP must be contained in the FTP server configuration.");
    }
    transferFile(true, serverCfg, fileToUpload, fileStoredName, null, null);
  } 

  /**
   * Download a file from FTP server
   *
   * @param serverCfg : FTP server configuration
   * @param fileNameToDownload : file name to be downloaded
   * @param fileStoredPath : stored path of the downloaded file in local
   * @throws SocketException
   * @throws IOException
   */
  public static final void download(Map<String, Object> serverCfg, String fileNameToDownload, String fileStoredPath)
      throws SocketException, IOException {
    if (StringUtils.isBlank(fileNameToDownload)) {
      throw new IllegalArgumentException("File name to be downloaded can not be blank.");
    }
    if (StringUtils.isBlank(fileStoredPath)) {
      throw new IllegalArgumentException("Stored path of the downloaded file in local can not be blank.");
    }
    if (StringUtils.isBlank((String) serverCfg.get(SERVER_IP))) {
      throw new IllegalArgumentException("SERVER_IP must be contained in the FTP server configuration.");
    }
    transferFile(false, serverCfg, null, null, fileNameToDownload, fileStoredPath);
  } 

  private static final void transferFile(boolean isUpload, Map<String, Object> serverCfg, File fileToUpload,
      String serverFileStoredName, String fileNameToDownload, String localFileStoredPath) throws  

SocketException,
      IOException {
    String host = (String) serverCfg.get(SERVER_IP);
    Integer port = (Integer) serverCfg.get(SERVER_PORT);
    Boolean isAnonymous = (Boolean) serverCfg.get(IS_ANONYMOUS);
    String username = (String) serverCfg.get(USER_NAME);
    String password = (String) serverCfg.get(PASSWORD);
    Boolean isPASV = (Boolean) serverCfg.get(IS_PASV);
    String workingDirectory = (String) serverCfg.get(WORKING_DIRECTORY);
    FTPClient ftpClient = new FTPClient();
    InputStream fileIn = null;
    OutputStream fileOut = null;
    try {
      if (port == null) {
        LOGGER.debug("Connect to FTP server on " + host + ":" + FTP.DEFAULT_PORT);
        ftpClient.connect(host);
      } else {
        LOGGER.debug("Connect to FTP server on " + host + ":" + port);
        ftpClient.connect(host, port);
      }
      int reply = ftpClient.getReplyCode();
      if (!FTPReply.isPositiveCompletion(reply)) {
        LOGGER.error("FTP server refuses connection");
        return;
      } 

      if (isAnonymous != null && isAnonymous) {
        username = ANONYMOUS_USER_NAME;
        password = ANONYMOUS_PASSWORD;
      }
      LOGGER.debug("Log in FTP server with username = " + username + ", password = " + password);
      if (!ftpClient.login(username, password)) {
        LOGGER.error("Fail to log in FTP server with username = " + username + ", password = " +  

password);
        ftpClient.logout();
        return;
      } 

      // Here we will use the BINARY mode as the transfer file type,
      // ASCII mode is not supportted.
      LOGGER.debug("Set type of the file, which is to upload, to BINARY.");
      ftpClient.setFileType(FTP.BINARY_FILE_TYPE); 

      if (isPASV != null && isPASV) {
        LOGGER.debug("Use the PASV mode to transfer file.");
        ftpClient.enterLocalPassiveMode();
      } else {
        LOGGER.debug("Use the ACTIVE mode to transfer file.");
        ftpClient.enterLocalActiveMode();
      } 

      if (StringUtils.isBlank(workingDirectory)) {
        workingDirectory = "/";
      } 

      LOGGER.debug("Change current working directory to " + workingDirectory);
      changeWorkingDirectory(ftpClient,workingDirectory); 

      if (isUpload) { // upload
        if (StringUtils.isBlank(serverFileStoredName)) {
          serverFileStoredName = fileToUpload.getName();
        }
        fileIn = new FileInputStream(fileToUpload);
        LOGGER.debug("Upload file : " + fileToUpload.getAbsolutePath() + " to FTP server with name : "
            + serverFileStoredName);
        if (!ftpClient.storeFile(serverFileStoredName, fileIn)) {
          LOGGER.error("Fail to upload file, " + ftpClient.getReplyString());
        } else {
          LOGGER.debug("Success to upload file.");
        }
      } else { // download
        // make sure the file directory exists
        File fileStored = new File(localFileStoredPath);
        if (!fileStored.getParentFile().exists()) {
          fileStored.getParentFile().mkdirs();
        }
        fileOut = new FileOutputStream(fileStored);
        LOGGER.debug("Download file : " + fileNameToDownload + " from FTP server to local : "
            + localFileStoredPath);
        if (!ftpClient.retrieveFile(fileNameToDownload, fileOut)) {
          LOGGER.error("Fail to download file, " + ftpClient.getReplyString());
        } else {
          LOGGER.debug("Success to download file.");
        }
      } 

      ftpClient.noop(); 

      ftpClient.logout(); 

    } finally {
      if (ftpClient.isConnected()) {
        try {
          ftpClient.disconnect();
        } catch (IOException f) {
        }
      }
      if (fileIn != null) {
        try {
          fileIn.close();
        } catch (IOException e) {
        }
      }
      if (fileOut != null) {
        try {
          fileOut.close();
        } catch (IOException e) {
        }
      }
    }
  } 

  private static final boolean changeWorkingDirectory(FTPClient ftpClient, String workingDirectory) throws IOException{
    if(!ftpClient.changeWorkingDirectory(workingDirectory)){
      String [] paths = workingDirectory.split("/");
      for(int i=0 ;i<paths.length ;i++){
        if(!"".equals(paths[i])){
          if(!ftpClient.changeWorkingDirectory(paths[i])){
            ftpClient.makeDirectory(paths[i]);
            ftpClient.changeWorkingDirectory(paths[i]);
          }
        }
      }
    }
    return true;
  } 

  public static final void upload(Map<String, Object> serverCfg, String filePathToUpload, String fileStoredPath, String  

fileStoredName)
      throws SocketException, IOException {
    upload(serverCfg, new File(filePathToUpload), fileStoredPath, fileStoredName);
  } 

  public static final void upload(Map<String, Object> serverCfg, File fileToUpload, String fileStoredPath, String  

fileStoredName)
      throws SocketException, IOException {
    if(fileStoredPath!=null && !"".equals(fileStoredPath)){
      serverCfg.put(WORKING_DIRECTORY, fileStoredPath);
    }
    upload(serverCfg, fileToUpload, fileStoredName);
  } 

  public static final void upload(String filePathToUpload, String fileStoredPath)throws SocketException, IOException {
    upload(serverCfg, filePathToUpload, fileStoredPath, "");
  } 

  public static final void upload(File fileToUpload, String fileStoredPath)throws SocketException, IOException {
    upload(serverCfg, fileToUpload, fileStoredPath, "");
  } 

  public static String values(String key) {
    String value = prop.getProperty(key);
    if (value != null) {
      return value;
    } else {
      return null;
    }
  } 

}

ftp.properties

#服务器地址
SERVER_IP=192.168.1.1 

#服务器端口
SERVER_PORT=21 

#帐号名
USER_NAME=userftp 

#密码
#PASSWORD=passwordftp 

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持我们。