SpringMVC上传下载文件

最新推荐文章于 2023-09-29 23:17:56 发布

原创最新推荐文章于 2023-09-29 23:17:56 发布 · 824 阅读

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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

   <!-- (2)配置 MultipartResolver 实现文件上传  
	              注意：id="multipartResolver"是固定写法
	   -->
	   <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
	     <!-- 字符编码 -->
	    <property name="defaultEncoding" value="utf-8"/>
	    <!-- max size 10M -->
	    <property name="maxUploadSize" value="10485760000"/>
	    <!--内存中最大 4K  -->
	    <property name="maxInMemorySize" value="4096"/>
	   </bean>

二、SpringMVC文件上传引入jar包

必须在配置Pom.xml文件

<!-- fileupload start -->
		<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>

		<!-- end -->

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"

<body>
	<div style="margin: 0 auto; margin-top: 100px; background:snow">
		<form method="post" action="upload1.html" name="form1"
			enctype="multipart/form-data">
			<p>
				  照片：<input type="file" name="imagefile">
				<input type="submit" value="上传" name="button1"> <br>
			</p>
		</form>
	</div>

(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

选择图片路径:

单击上传：

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"

<body>
	<div style="margin: 0 auto; margin-top: 100px; background:snow">
		<form method="post" action="upload2.html" name="form1"
			enctype="multipart/form-data">
			<p>
				  照片1：<input type="file" name="imagefile1"><p/>
				  照片2：<input type="file" name="imagefile2"><p/>
				<input type="submit" value="上传" name="button1"> <br>
			</p>
		</form>
	</div>
</body>

(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

	    <!--(1) spring 视图解析器 -->
	   <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

单击上传：

查看上传到服务器的图片

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

保存或打开如下: