Spring boot实现文件上传 Spring boot实现文件上传功能

时间:2021-03-31 卡通人物nnn 人气:0

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

1. MultipartResolver也可以实现文件上传功能。参考文章：

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