springmvc和servlet下的文件上传和下载（存文件目录和存数据库Blob两种方式）

时间：2021-03-21 12:54:14

项目中涉及了文件的上传和下载，以前在struts2下做过，今天又用springmvc做了一遍，发现springmvc封装的特别好，基本不用几行代码就完成了，下面把代码贴出来：


FileUpAndDown.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"%>
<html>
<head>
<title>using commons Upload to upload file</title>
</head>
<script type="text/javascript">
function downFile(){
var fileId = document.getElementById("fileId").value;
location.href="fileDownload?fileId=" + fileId;
}
</script>
<style>
* {
font-family: "宋体";
font-size: 14px
}
</style>
<body>
<p align="center">文件上传下载</p>
<form id="form1" name="form1" method="post" action="fileUpload" enctype="multipart/form-data">
<table border="0" align="center">
<tr>
<td>上传文件：</td>
<td><input name="file" type="file" size="20"></td>
</tr>
<tr>
<td></td>
<td><input type="submit" value="提交"> <input type="reset" name="reset" value="重置"></td>
</tr>
</table>
</form>
<div align="center">
<input type="text" id="fileId"><input type="button" value="根据Id下载文件" onclick="javascript:downFile()">
</div>
</body>
</html>

FileUpAndDownController.java 

@RequestMapping(value = "/fileUpload")
public String upload(
@RequestParam(value = "file", required = false) MultipartFile file,
HttpServletRequest request, ModelMap model) throws IOException {

/*
// 方式一:保存文件目录
try {
String path = request.getSession().getServletContext().getRealPath("/");// 文件保存目录，也可自定为绝对路径
String fileName = file.getOriginalFilename();// getOriginalFilename和getName是不一样的哦
System.out.println(path);
File targetFile = new File(path, fileName);
if (!targetFile.exists()) {
targetFile.mkdirs();
}
file.transferTo(targetFile);
model.addAttribute("upload.message", request.getContextPath() + "/upload/" + fileName);
} catch (Exception e) {
e.printStackTrace();
}
 */
// 方式二:保存入库
Map<String, Object> insertMap = new HashMap<String, Object>();
insertMap.put("byt", file.getBytes());
insertMap.put("fileName", file.getOriginalFilename());

int flag = fileUpAndDownMapper.saveFileInfo(insertMap);
if(flag > 0)
model.addAttribute("upload.message", "success");
else
model.addAttribute("upload.message", "failure");
return "/core/param/businessparam/uploadResult";
}

FileUpAndDownMapper.xml(对应的数据库为db2，保存blob类型) 

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper
namespace="com.xx.persistence.FileUpAndDownMapper">

<resultMap id="fileBean" type="com.xx.web.FileUpAndDown">
<id column="ID" property="id" jdbcType="INTEGER" />
<result column="FILENAME" property="fileName" jdbcType="VARCHAR" />
    <result column="TESTA" property="testa" javaType="byte[]" jdbcType="BLOB" typeHandler="org.apache.ibatis.type.BlobTypeHandler" />
    <result column="FILESTREAM" property="fileStream" javaType="byte[]" jdbcType="BLOB" typeHandler="org.apache.ibatis.type.BlobTypeHandler" />
</resultMap>  

<insert id="saveFileInfo" parameterType="java.util.HashMap">
INSERT INTO BLOBTEST(FILENAME, FILESTREAM)
VALUES(#{fileName}, #{byt, javaType=byte[], jdbcType=BLOB, typeHandler=org.apache.ibatis.type.BlobTypeHandler})
</insert>

    <select id="getFileByPk" resultMap="fileBean" parameterType="int">
      SELECT * FROM BLOBTEST WHERE ID=${value}
     </select>
</mapper>

uploadResult.jsp 

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>

<title>uploadResult</title>

<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
</head>
<body>
<a href="fileManagePage">上传文件</a> ${requestScope['upload.message'] }
</body>
</html>

以上为springmvc下上传文件的Demo，其中很关键的一步是，spring的配置文件中要加入文件上传的支持： 

<!-- 支持上传文件 -->
<bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver"/>

文件的保存做了两种方式，一种是直接存服务器的文件目录；另一种是把文件流存入数据库blob字段内（项目的特需要求）

下面是文件下载的代码：

@ResponseBody
@RequestMapping(value = "/fileDownload")
public void fileDownload(HttpServletRequest request,
HttpServletResponse response) throws IOException {
String fileId = request.getParameter("fileId");
FileUpAndDown file = fileUpAndDownMapper.getFileByPk(Integer.parseInt(fileId));
byte[] fileStream = file.getFileStream();
String fileName = file.getFileName();

// 以流的形式下载文件
response.setContentType("application/octet-stream");
response.setHeader("Content-Disposition", "attachment; filename=\"" + new String(fileName.getBytes("gb2312"), "ISO8859-1" ) + "\"");
OutputStream toClient = new BufferedOutputStream(response.getOutputStream());
toClient.write(fileStream);
toClient.flush();
toClient.close();
}

springmvc下文件上传下载很简单明了吧？不必像servlet下那么多的代码。












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