Spring实现文件上传功能

Spring实现文件上传功能

本篇文章，我们要来做一个Spring的文件上传功能：

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

org.springframework.boot

spring-boot-starter-web

1.0.2.RELEASE

2.在webapp目录下的index.jsp文件中输入一个表单：

action="/upload">

File to upload:
Name:

type="text" name="name">

value="Upload"> Press here to upload the file!

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

action="/batch/upload">

File to upload:

File to upload:

Press here to upload the file!

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;

impohttp://rt 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 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。

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