spring mvc 文件上传

本文介绍了通过导入架包的方式与使用maven依赖的方式分别使用springmvc框架实现单文件的上传主要逻辑流程，多文件上传留作后续更新。�

一 、 导入架包实现Spring MVC 文件上传到服务器本地

除了spring 架包外还需要org.apache.commons-fileupload-x.x.x.ja包的支持

springmvc.xml 中配置bean

<!-- 处理文件上传 -->
<!-- id="multipartResolver" 属于spring文件装配时的一个属性，名称固定不能改变！！！！ -->
  <bean id="multipartResolver"  
      class="org.springframework.web.multipart.commons.CommonsMultipartResolver" >  
      <property name="defaultEncoding" value="utf-8"/> <!-- 默认编码 (ISO-8859-1)  --> 
      <property name="maxInMemorySize" value="10240"/> <!-- 最大内存大小 (10240) -->  
      <property name="uploadTempDir" value="/upload/"/> <!-- 上传后的目录名 (WebUtils#TEMP_DIR_CONTEXT_ATTRIBUTE)  --> 
      <property name="maxUploadSize" value="-1"/><!--  最大文件大小，-1为无限止(-1) -->  
  </bean>

jsp 界面的处理 特别注意单词的拼写：enctype = "multipart/form-data"

<form action="/RestMyibatisSpring/file/upload" method="post" enctype = "multipart/form-data">
   <!-- <input type = "hidden" name = "method" value ="upload"> -->
   <input type = "text" name = "fileName" >
   <input type = "file" name = "file" >
   <input type = "submit" value = "上传文件">
</form>

设置相应的controller处理

import java.io.File;

import javax.servlet.ServletContext;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.context.ServletContextAware;
import org.springframework.web.multipart.commons.CommonsMultipartFile;

@Controller
@RequestMapping("/file")
public class FileController_Rest implements ServletContextAware{
private ServletContext servletContext;
   
   @Override
   public void setServletContext(ServletContext arg0) {
       this.servletContext = arg0;
   }
   
   @RequestMapping(value="/upload",method = RequestMethod.POST)
   public String uploadFile(String fileName,@RequestParam("file")CommonsMultipartFile file) {
       if (!file.isEmpty()) {
           String path = this.servletContext.getRealPath("/upload");
           String oriFileName = file.getOriginalFilename();
           
           String fileType = oriFileName.substring(oriFileName.lastIndexOf("."));
           String newFileName = fileName + fileType;
           File newFile = new File(path + "/" + newFileName);
           try {
               file.getFileItem().write(newFile);
           } catch (Exception e) {
               e.printStackTrace();
           }
       }
       return "/jsps/upload";
   }
}

二、 maven 使用spring 上传文件到hdfs系统

spring使用文件上传功能处理springmvc的基础包之外还需要两个库
commons-fileupload-1.2.2.jar，commons-io-2.0.1.jar的支持
使用maven的直接导入commons-fileupload依赖就可以了，commons-fileupload会自动下载io依赖包

    <!-- https://mvnrepository.com/artifact/commons-fileupload/commons-fileupload -->
    <dependency>
        <groupId>commons-fileupload</groupId>
        <artifactId>commons-fileupload</artifactId>
        <version>1.3.2</version>
    </dependency>

![enter description here][4]

然后springmvc.xml中要配置spring的相关依赖

    <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
        <property name="defaultEncoding" value="utf-8"/>
    </bean>

jsp界面代码如下

<form id="uploadFile" action="/cd/fileIndex/uploadFile" method="post"  enctype="multipart/form-data">
    <div class=":form-group">
        <label>选择文件</label>
        <input id="file" type="file" name="file" class="form-control"/>
        <input type="hidden" name="parentId" value="<%=rootDir.getFileIndexId()%>"/>
        <input type="hidden" name="parentPath" value="<%=rootDir.getPath()%>"/>
    </div>
</form>

Java代码如下

controller

    @RequestMapping(value="/uploadFile",method=RequestMethod.POST)
    public String uploadFile(@RequestParam(value="file",required=false) MultipartFile file
            ,@SessionAttribute("loginUser") AppUser loginUser,String parentId,String parentPath) 
                    throws IllegalArgumentException, IOException, NoSuchAlgorithmException{
        //接受前台传输过来的文件并保存在hdfs上
        String fileName = file.getOriginalFilename();
        InputStream fStream = file.getInputStream();
        
        Long fileSize = file.getSize();
        
        String pathStr = "/user/root/clouddisk/" + fileName;
        String md5 = HDFSUtil.upLoadFileToHdfs(fStream, pathStr);
        
        return "redirect:/fileIndex/openDirectory?dirId=" + parentId;
    }

HDFSUtil.java

import java.io.IOException;
import java.io.InputStream;
import java.math.BigInteger;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Arrays;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FSDataOutputStream;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;

public class HDFSUtil {
    public static final Configuration CONFIGURATION = new Configuration();

    // 获取FileSystem 对象
    public static FileSystem getFileSystem() {
        try {
            return FileSystem.get(CONFIGURATION);
        } catch (IOException e) {
            e.printStackTrace();
            return null;
        }
    }

    public static String upLoadFileToHdfs(InputStream iStream, String pathStr)
            throws IllegalArgumentException, IOException, NoSuchAlgorithmException {

        FileSystem fileSystem = HDFSUtil.getFileSystem();

        FSDataOutputStream outputStream = fileSystem.create(new Path(pathStr));
        
        byte[] buffer = new byte[1024];
        

        MessageDigest mDigest = MessageDigest.getInstance("MD5");
        int lenth = iStream.read(buffer,0,1024);
        while (lenth > -1) {
            //保证文件不失真
            if (lenth < 1024) {
                byte[] lastBuffer = Arrays.copyOf(buffer, lenth);
                mDigest.update(lastBuffer);
                outputStream.write(lastBuffer);
                
            } else {
                mDigest.update(buffer);
                outputStream.write(buffer);
            }
            lenth = iStream.read(buffer, 0, lenth);
            System.out.println("read" + lenth);
            
        }
        outputStream.hsync();
        outputStream.close();
        iStream.close();
        fileSystem.close();
        BigInteger bigInteger = new BigInteger(1, mDigest.digest());
        return bigInteger.toString(16);
        
    }
}