Spring boot实现文件上传功能

本文实例为大家分享了Spring boot实现文件上传的具体代码，供大家参考，具体内容如下

1. 创建一个Maven的web工程，然后配置pom.xml文件，增加依赖：

<dependency>
 <groupId>org.springframework.boot</groupId>
 <artifactId>spring-boot-starter-web</artifactId>
 <version>1.0.2.RELEASE</version>
</dependency> 

2. 在webapp目录下的index.jsp文件中输入一个表单：

<html>
<body>
<form method="POST" enctype="multipart/form-data" action="/upload">
 File to upload: <input type="file" name="file"><br />
 Name: <input type="text" name="name"><br /> <br />
 <input type="submit" value="Upload">
  Press here to upload the file!
</form>
</body>

这个表单就是我们模拟的上传页面

3. 编写处理这个表单的Controller：

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

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.bind.annotation.ResponseBody;
import org.springframework.web.multipart.MultipartFile; 

@Controller
public class FileUploadController { 

 @RequestMapping(value="/upload", method=RequestMethod.GET)
 public @ResponseBody String provideUploadInfo() {
  return "You can upload a file by posting to this same URL.";
 } 

 @RequestMapping(value="/upload", method=RequestMethod.POST)
 public @ResponseBody String handleFileUpload(@RequestParam("name") String name,
   @RequestParam("file") MultipartFile file){
  if (!file.isEmpty()) {
   try {
    byte[] bytes = file.getBytes();
    BufferedOutputStream stream =
      new BufferedOutputStream(new FileOutputStream(new File(name + "-uploaded")));
    stream.write(bytes);
    stream.close();
    return "You successfully uploaded " + name + " into " + name + "-uploaded !";
   } catch (Exception e) {
    return "You failed to upload " + name + " => " + e.getMessage();
   }
  } else {
   return "You failed to upload " + name + " because the file was empty.";
  }
 } 

} 

4. 然后我们对上传的文件做一些限制，同时编写main方法来启动这个web ：

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.boot.context.embedded.MultiPartConfigFactory;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration; 

import javax.servlet.MultipartConfigElement; 

@Configuration
@ComponentScan
@EnableAutoConfiguration
public class Application { 

 @Bean
 public MultipartConfigElement multipartConfigElement() {
  MultiPartConfigFactory factory = new MultiPartConfigFactory();
  factory.setMaxFileSize("128KB");
  factory.setMaxRequestSize("128KB");
  return factory.createMultipartConfig();
 } 

 public static void main(String[] args) {
  SpringApplication.run(Application.class, args);
 }
} 

5. 然后访问http://localhost:8080/upload就可以看到页面了。

上面的例子是实现的是单个文件上传的功能，假定我们现在要实现文件批量上传的功能的话，我们只需要简单的修改一下上面的代码就行，考虑到篇幅的问题，下面只是贴出和上面不同的代码，没有贴出的说明和上面一样。：

1.新增batchUpload.jsp文件

<html>
<body>
<form method="POST" enctype="multipart/form-data"
  action="/batch/upload">
 File to upload: <input type="file" name="file"><br />
 File to upload: <input type="file" name="file"><br />
 <input type="submit" value="Upload"> Press here to upload the file!
</form>
</body>
</html>

2. 新增BatchFileUploadController.java文件：

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.ResponseBody;
import org.springframework.web.multipart.MultipartFile;
import org.springframework.web.multipart.MultipartHttpServletRequest; 

import javax.servlet.http.HttpServletRequest;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.util.List; 

/**
 * Created by wenchao.ren on 2014/4/26.
 */ 

@Controller
public class BatchFileUploadController { 

 @RequestMapping(value="/batch/upload", method= RequestMethod.POST)
 public @ResponseBody
 String handleFileUpload(HttpServletRequest request){
  List<MultipartFile> files = ((MultipartHttpServletRequest)request).getFiles("file");
  for (int i =0; i< files.size(); ++i) {
   MultipartFile file = files.get(i);
   String name = file.getName();
   if (!file.isEmpty()) {
    try {
     byte[] bytes = file.getBytes();
     BufferedOutputStream stream =
       new BufferedOutputStream(new FileOutputStream(new File(name + i)));
     stream.write(bytes);
     stream.close();
    } catch (Exception e) {
     return "You failed to upload " + name + " => " + e.getMessage();
    }
   } else {
    return "You failed to upload " + name + " because the file was empty.";
   }
  }
  return "upload successful";
 }
} 

这样一个简单的批量上传文件的功能就ok了，是不是很简单啊。

注意：上面的代码只是为了演示而已，所以编码风格上采取了随性的方式，不建议大家模仿。

参考资料：MultipartResolver实现文件上传功能

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。

1. MultipartResolver也可以实现文件上传功能。参考文章：