SpringBoot上传下载

额外加入的依赖

<dependency>
      <groupId>commons-io</groupId>
      <artifactId>commons-io</artifactId>
      <version>2.4</version>
    </dependency>

上传

上传页面：注意上传域的name属性要和controller参数名一致，enctype属性

<form method="POST" enctype="multipart/form-data" action="fileUpLoad.action">
    <p>
      文件：<input type="file" name="file" />
    </p>
    <p>
      <input type="submit" value="上传" />
    </p>
  </form>

上传参数控制

package com.example.demo.config;

import javax.servlet.MultipartConfigElement;

import org.springframework.boot.web.servlet.MultipartConfigFactory;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
/**
 * 配置上传
 * @author 柴火
 *
 */
@Configuration
public class FileUpLoadConfig {
  
  @Bean
  public MultipartConfigElement multipartConfigElement() {
    MultipartConfigFactory factory = new MultipartConfigFactory(); 
     设置文件大小限制,超了，页面会抛出异常信息，这时候就需要进行异常信息的处理了;
    factory.setMaxFileSize("128KB"); // KB,MB 
    /// 设置总上传数据总大小
    factory.setMaxRequestSize("256KB"); 
    // Sets the directory location where files will be stored. 设置上传路径
    //factory.setLocation("路径地址");
    return factory.createMultipartConfig();
  }
}

controller代码（2种上传方式）

package com.example.demo.controller;

import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.multipart.MultipartFile;

@Controller
public class UpLoadController {

  @RequestMapping("/fileUpLoad.action")
  @ResponseBody
  public String upLoadFile(MultipartFile file) throws IllegalStateException, IOException {
    BufferedOutputStream stream = null;
    if (!file.isEmpty()) {

      
      String path = "E:/stsWorkSpace/SpringBoot_Test/src/main/resources/upload";
      File newFile=new File(path+"/"+file.getOriginalFilename());
      if(!newFile.exists()){
        newFile.createNewFile();
      }
      BufferedOutputStream out = new BufferedOutputStream(new FileOutputStream(newFile)); 
      out.write(file.getBytes()); 
      out.flush(); 
      out.close(); 
      
      

      return "上传成功";
    }
    return "上传失败";
  }

}

package com.example.demo.controller;

import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.multipart.MultipartFile;

@Controller
public class UpLoadController {

  @RequestMapping("/fileUpLoad.action")
  @ResponseBody
  public String upLoadFile(MultipartFile file) throws IllegalStateException, IOException {
    BufferedOutputStream stream = null;
    if (!file.isEmpty()) {

      
      // 打印文件的名称
      System.out.println("FileName:" + file.getOriginalFilename());
      // 确定上传文件的位置
      String path = "E:/stsWorkSpace/SpringBoot_Test/src/main/resources/upload";
      
      File newFile = new File(path, file.getOriginalFilename());
      //如果不存在，创建一哥副本
      if (!newFile.exists()) {
        newFile.createNewFile();
    
      }
        
      //将io上传到副本中
      file.transferTo(newFile);
                  

      return "上传成功";
    }
    return "上传失败";
  }

}

下载

package com.example.demo.controller;

import java.io.File;

import org.apache.commons.io.FileUtils;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
public class DownLoadController {
  
  @RequestMapping("/fileDownLoad.action")
  public ResponseEntity<byte[]> textFileDownload() throws Exception {
  
    String path = "E:/WorkSpace1/SpringMVC_001/WebContent/WEB-INF/fileupload/1.jpg";
    File file = new File(path);
    HttpHeaders headers = new HttpHeaders();
    // String fileName=new
    // String("你好.xlsx".getBytes("UTF-8"),"iso-8859-1");//为了解决中文名称乱码问题
    String fileName = new String(file.getName().getBytes("UTF-8"), "iso-8859-1");// 为了解决中文名称乱码问题
    headers.setContentDispositionFormData("attachment", fileName);
    headers.setContentType(MediaType.APPLICATION_OCTET_STREAM);
    return new ResponseEntity<byte[]>(FileUtils.readFileToByteArray(file), headers, HttpStatus.CREATED);
    
    
  }

}