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29. Spring boot 文件上传(多文件上传)【从零开始学Spring Boot】

2016-12-29 09:26 501 查看
文件上传主要分以下几个步骤

(1)新建maven
Java project;
(2)在pom.xml加入相应依赖;
(3)新建一个表单页面(这里使用thymeleaf);
(4)编写controller;
(5)测试
(6)对上传的文件做一些限制;
(7)多文件上传实现
(1)新建maven
Java project


新建一个名称为spring-boot-fileuploadmaven java项目;

 

(2)在pom.xml加入相应依赖;

加入相应的maven依赖,具体看以下解释:

<!--
              springboot父节点依赖,
             引入这个之后相关的引入就不需要添加version配置,
              springboot会自动选择最合适的版本进行添加。
        -->
      
<parent>
             
<groupId>org.springframework.boot</groupId>
             
<artifactId>spring-boot-starter-parent</artifactId>
             
<version>1.3.3.RELEASE</version>
      
</parent>
 <dependencies>
         
<!-- spring boot web支持:mvc,aop... -->
             
<dependency>
                    
<groupId>org.springframework.boot</groupId>
                    
<artifactId>spring-boot-starter-web</artifactId>
             
</dependency>
             
<!-- thmleaf模板依赖. -->
             
<dependency>
               
<groupId>org.springframework.boot</groupId>
               
<artifactId>spring-boot-starter-thymeleaf</artifactId>
             
</dependency>
 </dependencies>
    
<build>
             
<plugins>
                    
<!-- 编译版本; -->
                    
<plugin>
                           
<artifactId>maven-compiler-plugin</artifactId>
                           
<configuration>
                                  <source>1.8</source>
                                  <target>1.8</target>
                           
</configuration>
                    
</plugin>
             
</plugins>
       </build>
 

(3)新建一个表单页面(这里使用thymeleaf)

在src/main/resouces新建templates(如果看过博主之前的文章,应该知道,templates是spring boot存放模板文件的路径),在templates下新建一个file.html:

 

<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml"xmlns:th="http://www.thymeleaf.org"
     xmlns:sec="http://www.thymeleaf.org/thymeleaf-extras-springsecurity3">
   <head>
       <title>Hello World!</title>
   </head>
   <body>
      <form method="POST"
enctype
="multipart/form-data"action="/upload"> 
              <p>文件:<input type="file" name="file"/></p>
          <p><input type="submit" value="上传" /></p>
      </form>
   </body>
</html>
 

(4)编写controller;

       编写controller进行测试,这里主要实现两个方法:其一就是提供访问的/file路径;其二就是提供post上传的/upload方法,具体看代码实现:

package com.kfit;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
 
importorg.springframework.stereotype.Controller;
importorg.springframework.web.bind.annotation.RequestMapping;
importorg.springframework.web.bind.annotation.RequestParam;
importorg.springframework.web.bind.annotation.ResponseBody;
importorg.springframework.web.multipart.MultipartFile;
 
@Controller
publicclass FileUploadController {
      
      
//访问路径为:http://127.0.0.1:8080/file
      
@RequestMapping("/file")
       public String file(){
              return"/file";
       }
      
      
/**
        *文件上传具体实现方法;
        *@param file
        *@return
        */
      
@RequestMapping("/upload")
      
@ResponseBody
       public StringhandleFileUpload(@RequestParam("file")MultipartFilefile){
              if(!file.isEmpty()){
                    
try
{
                           
/*
                             *这段代码执行完毕之后,图片上传到了工程的跟路径;
                             *大家自己扩散下思维,如果我们想把图片上传到 d:/files大家是否能实现呢?
                             *等等;
                             *这里只是简单一个例子,请自行参考,融入到实际中可能需要大家自己做一些思考,比如:
                             * 1、文件路径;
                             * 2、文件名;
                             * 3、文件格式;
                             * 4、文件大小的限制;
                             */
                            BufferedOutputStreamout =newBufferedOutputStream(new
FileOutputStream(new File(file.getOriginalFilename())));
                           
out.write(file.getBytes());
                           
out.flush();
                           
out.close();
                     }catch(FileNotFoundExceptione) {
                           
e.printStackTrace();
                           
return
"上传失败,"+e.getMessage();
                     }catch (IOExceptione) {
                           
e.printStackTrace();
                           
return
"上传失败,"+e.getMessage();
                     }
                    
return
"上传成功";
              }else{
                    
return
"上传失败,因为文件是空的.";
              }
       }
}
 

(5)编写App.java然后测试

       App.java没什么代码,就是Spring Boot的启动配置,具体如下:

package com.kfit;
 
importorg.springframework.boot.SpringApplication;
importorg.springframework.boot.autoconfigure.SpringBootApplication;
 
/**
 * Hello world!
 *
 */
//其中@SpringBootApplication申明让spring boot自动给程序进行必要的配置,等价于以默认属性使用@Configuration,@EnableAutoConfiguration和@ComponentScan
@SpringBootApplication
publicclass App {
       publicstatic
void
main(String[]args) {
              SpringApplication.run(App.class,args);
       }
}
 

然后你就可以访问:http://127.0.0.1:8080/file进行测试了,文件上传的路径是在工程的跟路径下,请刷新查看,其它的请查看代码中的注释进行自行思考。

 

(6)对上传的文件做一些限制;

 

       对文件做一些限制是有必要的,在App.java进行编码配置:

@Bean 
   public MultipartConfigElement multipartConfigElement() { 
        MultipartConfigFactoryfactory =
newMultipartConfigFactory();
       
//// 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 wherefiles will be stored.
       
//factory.setLocation("路径地址");
        returnfactory.createMultipartConfig(); 

    } 
 

(7)多文件上传实现

       多文件对于前段页面比较简单,具体代码实现:

在src/resouces/templates/mutifile.html

<!DOCTYPEhtml>
<htmlxmlns="http://www.w3.org/1999/xhtml"xmlns:th="http://www.thymeleaf.org"
     
xmlns:sec="http://www.thymeleaf.org/thymeleaf-extras-springsecurity3">
   <head>
       
<title>Hello World!</title>
   </head>
   <body>
      <formmethod="POST"enctype="multipart/form-data"action="/batch/upload"> 
             <p>文件1:<inputtype="file"name="file"/></p>
             <p>文件2:<inputtype="file"name="file"/></p>
             <p>文件3:<inputtype="file"name="file"/></p>
          
<p><inputtype="submit"value="上传"/></p>
      </form>
   </body>
</html>
com.kfit.FileUploadController中新增两个方法:

/**
        *多文件具体上传时间,主要是使用了MultipartHttpServletRequest和MultipartFile
        *@param request
        *@return
        */
      
@RequestMapping(value="/batch/upload", method=RequestMethod.POST
   public@ResponseBody 

   String handleFileUpload(HttpServletRequestrequest){ 
        List<MultipartFile>
files =((MultipartHttpServletRequest)request).getFiles("file"); 
        MultipartFile
file = null;
        BufferedOutputStream
stream = null;
        for (inti =0;
i< files.size(); ++i) { 
           
file = files.get(i); 
            if (!file.isEmpty()) { 
                try
                    byte[]bytes =
file.getBytes(); 
                   
stream = 
                           
new
BufferedOutputStream(new FileOutputStream(new File(file.getOriginalFilename()))); 
                   
stream.write(bytes); 
                   
stream.close(); 
                } catch (Exceptione) { 
                      
stream =  null;
                    return"You failed to upload " +
i + " =>" +
e.getMessage(); 
                } 
            } else
                return"You failed to upload " +
i + " becausethe file was empty."; 

            } 
        } 
        return"upload successful"; 

    } 
 

访问路径:http://127.0.0.1:8080/mutifile进行测试。
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