MultipartResolver实现文件上传 MultipartResolver实现文件上传功能

时间:2021-03-31 紫_色人气:0

springMVC默认的解析器里面是没有加入对文件上传的解析的,，使用springmvc对文件上传的解析器来处理文件上传的时需要用springmvc提供的MultipartResolver的申明，又因为CommonsMultipartResolver实现了MultipartResolver接口，所以我们可以在springmvc配置文件中这样配置：

 <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="40960" /> 
  </bean>

首先引入文件上传所需要的包,commons-logging-*.jar commons-io-*.jar commons-fileupload-*.jar

新建一个JSP页面.

<%@ page language="java" contentType="text/html; charset=UTF-8" 
  pageEncoding="UTF-8"%> 
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 
<html> 
<head> 
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 
<title>文件上传</title> 
</head> 
<body> 
  <%--<form action="user/fileUpload" method="post" enctype="multipart/form-data">--%> 
  <form action="user/fileUpload" method="post" enctype="multipart/form-data"> 
    <input type="file" name="fileUpload" /> 
    <input type="submit" value="上传" /> 
  </form> 
</body> 
</html>

springmvc上传文件的形式有很多,这里我介绍两种.

第一种,看Controller

package gd.hz.springmvc.controller; 
 
import java.io.File; 
import java.io.IOException; 
 
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.multipart.commons.CommonsMultipartFile; 
import org.springframework.web.servlet.ModelAndView; 
 
@Controller("userController") 
@RequestMapping("user") 
public class UserController { 
 
  // 处理文件上传一 
  @RequestMapping(value = "fileUpload", method = RequestMethod.POST) 
  public ModelAndView fileUpload( 
      @RequestParam("fileUpload") CommonsMultipartFile file) { 
    // 获取文件类型 
    System.out.println(file.getContentType()); 
    // 获取文件大小 
    System.out.println(file.getSize()); 
    // 获取文件名称 
    System.out.println(file.getOriginalFilename()); 
 
    // 判断文件是否存在 
    if (!file.isEmpty()) { 
      String path = "D:/" + file.getOriginalFilename(); 
      File localFile = new File(path); 
      try { 
        file.transferTo(localFile); 
      } catch (IllegalStateException e) { 
        e.printStackTrace(); 
      } catch (IOException e) { 
        e.printStackTrace(); 
      } 
    } 
    return new ModelAndView("dataSuccess"); 
  } 
}

类CommonsMultipartFile为我们提供了许多对文件处理的方法.例如文件大小,上传文件名称,文件类型,具体用法可以查看spring的文档.transferTo就是将文件输出到指定地方.

文件上传的第二种方法,这种方法比较常用:

package gd.hz.springmvc.controller; 
 
import java.io.File; 
import java.io.IOException; 
import java.util.Iterator; 
 
import javax.servlet.http.HttpServletRequest; 
 
import org.springframework.stereotype.Controller; 
import org.springframework.web.bind.annotation.RequestMapping; 
import org.springframework.web.bind.annotation.RequestMethod; 
import org.springframework.web.multipart.MultipartFile; 
import org.springframework.web.multipart.MultipartHttpServletRequest; 
import org.springframework.web.multipart.commons.CommonsMultipartResolver; 
 
@Controller("userController") 
@RequestMapping("user") 
public class UserController { 
 
  // 处理文件上传二 
  @RequestMapping(value = "fileUpload2", method = RequestMethod.POST) 
  public String fileUpload2(HttpServletRequest request) 
      throws IllegalStateException, IOException { 
    // 设置上下方文 
    CommonsMultipartResolver multipartResolver = new CommonsMultipartResolver( 
        request.getSession().getServletContext()); 
 
    // 检查form是否有enctype="multipart/form-data" 
    if (multipartResolver.isMultipart(request)) { 
      MultipartHttpServletRequest multiRequest = (MultipartHttpServletRequest) request; 
 
      Iterator<String> iter = multiRequest.getFileNames(); 
      while (iter.hasNext()) { 
 
        // 由CommonsMultipartFile继承而来,拥有上面的方法. 
        MultipartFile file = multiRequest.getFile(iter.next()); 
        if (file != null) { 
          String fileName = "demoUpload" + file.getOriginalFilename(); 
          String path = "D:/" + fileName; 
 
          File localFile = new File(path); 
          file.transferTo(localFile); 
        } 
 
      } 
    } 
    return "dataSuccess"; 
  } 
}

MultipartHttpServletRequest提供了更加灵活的方法,可以获取多个文件和文件名,可以遍历获得每个文件.

加载全部内容