Spring实现文件上传功能

2024-07-13 10:03:31

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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：

<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></html>

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; @Controllerpublic 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@EnableAutoConfigurationpublic 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. */ @Controllerpublic 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。

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VeVb武林网。

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