本文实例为大家分享了SpringMVC实现上传下载文件的具体代码，供大家参考，具体内容如下 一、SpringMVC专门提供了CommonsMultipartResolver组件用于文件上传： （1）maxUploadSize 文件最大限制，
本文实例为大家分享了SpringMVC实现上传下载文件的具体代码，供大家参考，具体内容如下
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%>" rel="external nofollow" ><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
<a href="download.html?fileName=08.gif" >下载图片</a><p/>
(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:
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自由互联。