SpringMVC上传下载文件

叁歲伎倆 2023-10-17 08:04 70阅读 0赞

**一、SpringMVC专门提供了CommonsMultipartResolver组件用于文件上传：**

（1）maxUploadSize文件最大限制，单位是byte

（2）maxInMemorySize低于这个大小的文件暂存内存中

（3）defaultEncoding默认编码utf-8

**必须在spring-mvc.xml文件**

<bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
    	     
    	    <property name="defaultEncoding" value="utf-8"/>
    	    
    	    <property name="maxUploadSize" value="10485760000"/>
    	    
    	    <property name="maxInMemorySize" value="4096"/>
    	   </bean>

**二、SpringMVC文件上传引入jar包**

**![Center][]**

**必须在配置Pom.xml文件**

<dependency>
    			<groupId>commons-fileupload</groupId>
    			<artifactId>commons-fileupload</artifactId>
    			<version>1.3.1</version>
    		</dependency>
    
    		<dependency>
    			<groupId>commons-io</groupId>
    			<artifactId>commons-io</artifactId>
    			<version>2.4</version>
    		</dependency>

**三、实现【单个文件】上传**

（1）JSP页面必须放在WEB-INF下 upload1.jsp 必须添加enctype="multipart/form-data"

(2) 写控制类 UploadController.java

@Controller
    public class UploadController {
    
    	@RequestMapping("upload1")
    	public String getUpload(@RequestParam("imagefile") MultipartFile imagefile,
    			HttpServletRequest request) {
    		// 获取上传的服务器路径
    		String pathString = request.getSession().getServletContext().getRealPath("/upload/");
    		// 获取文件
    		String fileName = imagefile.getOriginalFilename();
    		
    		System.out.println(fileName);
    
    		// 判断上传的路径是否存在
    		File file = new File(pathString);
    		if (!file.exists()) {
    			file.mkdirs();
    		}
    
    		System.out.println("上传路径=" + pathString +"/"+ fileName);
    		// 文件不存在
    		File targetFile = new File(pathString +"/"+ fileName);
    		if (!targetFile.exists()) {
    			try {
    				targetFile.createNewFile();
    			} catch (IOException e) {
    				// TODO Auto-generated catch block
    				e.printStackTrace();
    			}
    		}
    
    		try {
    			// 上传
    			imagefile.transferTo(targetFile);
    		} catch (IllegalStateException e) {
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		} catch (IOException e) {
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		}
    
    		//注意：/springmvc5/WEB-INF/jsp/http:/localhost:8888/springmvc5/upload/1.gif.jsp
    		//返回文件，必须是重定向文件
    		return "redirect:http://localhost:8888/springmvc5/upload/" + fileName;
    
    	} }

(3)效果

![Center 1][]

选择图片路径:

![Center 2][]

单击上传：

![Center 3][]

**四、实现【多个文件】上传**

**（1）JSP页面(必须放在WEB-INF下) upload2.jsp  必须添加enctype="multipart/form-data"**

(2) 写控制类 UploadController.java

@RequestMapping("upload2")
    	public String getUpload2(HttpServletRequest request) {
    
    		// 多文件上传
    		MultipartHttpServletRequest multipartRequest = (MultipartHttpServletRequest) request;
    		// 获得多个文件
    		Map<String, MultipartFile> map = multipartRequest.getFileMap();
    
    		// 获取上传的服务器路径
    		String pathString = request.getSession().getServletContext().getRealPath("/upload/");
    		// 判断上传的路径是否存在
    		File file1 = new File(pathString);
    		if (!file1.exists()) {
    			file1.mkdirs();
    		}
    
    		// 获取文件
    		List<String> list = new ArrayList<String>();
    
    		// 遍历数据
    		for (MultipartFile file : map.values()) {
    			String fileName = file.getOriginalFilename();
    			System.out.println("上传路径=" + pathString +"/"+ fileName);
    			// 文件不存在
    			File targetFile = new File(pathString  +"/"+ fileName);
    			if (!targetFile.exists()) {
    				try {
    					targetFile.createNewFile();
    				} catch (IOException e) {
    					// TODO Auto-generated catch block
    					e.printStackTrace();
    				}
    			}
    
    			try {
    				// 上传
    				file.transferTo(targetFile);
    
    				// 保存路径
    				list.add("http://localhost:8888/springmvc5/upload/" + fileName);
    			} catch (IllegalStateException e) {
    				// TODO Auto-generated catch block
    				e.printStackTrace();
    			} catch (IOException e) {
    				// TODO Auto-generated catch block
    				e.printStackTrace();
    			}
    
    		}
    		// 保存每个上传的路径
    		request.setAttribute("files", list);
    		
    		return "showUpload";   //跳转到showUpload.jsp页面哦！
    
    	}

注意：return "showUpload";是具体显示的页面;必须配置视图解析器在spring-mvc.xml文件中

<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"
    	   p:prefix="/WEB-INF/jsp/"  p:suffix=".jsp"></bean>

(3)JSP页面: showUpload.jsp

<div style="margin: 0 auto; margin-top: 100px; background:snow">
    	  <%
    	    List<String> list =(List<String>) request.getAttribute("files");
    	    
    	    for(String str:list){
    	  
    	   %>
    	      <a href="<%=str%>"><img src="<%=str%>" alt=""/></a>
    	   
    	   <%} %>
    	</div>

(4)效果

![Center 4][]

单击上传：

![Center 5][]

**查看上传到服务器的图片**

![Center 6][]

**五、下载图片**

**（1）JSP页面 login.jsp**

**(2)控制类DownController**

@Controller
    public class DownController {
    
    	@RequestMapping("/download")
    	public String download(@RequestParam String fileName,
    			HttpServletRequest request, HttpServletResponse response) {
    
    		// 设置响应编码
    		response.setContentType("text/html;charset=utf-8");
    
    		// 设置请求编码
    		try {
    			request.setCharacterEncoding("utf-8");
    		} catch (UnsupportedEncodingException e) {
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		}
    
    		// 字节流
    		BufferedInputStream bis=null;
    		BufferedOutputStream bos=null;
    
    		// 获取服务器的路径
    		String path = request.getSession().getServletContext().getRealPath("/upload/");
    
    		// 下载的路径
    		String downPath = path +"/"+ fileName;
    
    		try {
    			// 文件大小
    			long fileSize = new File(downPath).length();
    			
    			//设置内容类型
    			response.setContentType("application/x-msdownload");
    			//设置头信息
    			response.setHeader("Content-disposition", "attachment; filename="+new String(fileName.getBytes("utf-8"),"ISO8859-1"));
    			response.setHeader("Content-Length",String.valueOf(fileSize));
    			//字节流
    			bis = new BufferedInputStream(new FileInputStream(downPath));
    			bos= new BufferedOutputStream(response.getOutputStream());
    			//字节数组
    			byte[] by = new byte[2048];
    			
    			//
    			int length=0;
    			
    			//读取
    			while((length=bis.read(by,0,by.length))!=-1){
    				//写入
    				bos.write(by, 0, length);
    				
    			}
    			
    		} catch (Exception e) {
    			// TODO: handle exception
    			e.printStackTrace();
    		}finally{
    			//关闭连接
    			 if(bis!=null){
    				 try {
    					bis.close();
    				} catch (IOException e) {
    					// TODO Auto-generated catch block
    					e.printStackTrace();
    				}
    			 }
    			 if(bos!=null){
    				 try {
    					 bos.close();
    				 } catch (IOException e) {
    					 // TODO Auto-generated catch block
    					 e.printStackTrace();
    				 }
    			 }
    		}
    
    		return null;
    
    	}
    }

(3)效果

**![Center 7][]**

**保存或打开如下:**

**![Center 8][]**

[Center]: https://img-blog.csdn.net/20160721104034204?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQv/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/Center
[Center 1]: https://img-blog.csdn.net/20160721105010177?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQv/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/Center
[Center 2]: https://img-blog.csdn.net/20160721105053334?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQv/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/Center
[Center 3]: https://img-blog.csdn.net/20160721105114336?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQv/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/Center
[Center 4]: https://img-blog.csdn.net/20160721105919800?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQv/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/Center
[Center 5]: https://img-blog.csdn.net/20160721105948379?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQv/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/Center
[Center 6]: https://img-blog.csdn.net/20160721110115041?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQv/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/Center
[Center 7]: https://img-blog.csdn.net/20160721111238702?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQv/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/Center
[Center 8]: https://img-blog.csdn.net/20160721111246796?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQv/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/Center