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MyBatis与SpringMVC相结合实现文件上传、下载功能

作者:Alfa

这篇文章主要介绍了MyBatis与SpringMVC相结合实现文件上传、下载功能的相关资料,非常不错,具有参考借鉴价值,需要的朋友可以参考下

环境:maven+SpringMVC + Spring + MyBatis + MySql

本文主要说明如何使用input上传文件到服务器指定目录,或保存到数据库中;如何从数据库下载文件,和显示图像文件并实现缩放。

将文件存储在数据库中,一般是存文件的byte数组,对应的数据库数据类型为blob。

首先要创建数据库,此处使用MySql数据库。

注意:文中给出的代码多为节选重要片段,并不齐全。

1. 前期准备

使用maven创建一个springMVC+spring+mybatis+mysql的项目。

关于如何整合Spring+mybatis+mysql,请见MyBatis简介与配置MyBatis+Spring+MySql:

MyBatis学习 之 一、MyBatis简介与配置MyBaits+Spring+MySql

关于SpringMVC环境的搭建请见:使用Eclipse构建Maven的SpringMVC项目:

使用Eclipse构建Maven的SpringMVC项目

在前台html中,form的enctype为multipart/form-data。注意input、select的name要和StudentForm中成员一一对应。

上传的url为addAction.do,此action方法的参数中使用StudentForm来映射提交的数据。此时就可以获取到提交的文件的数据。然后我们就对文件进行操作。

创建PHOTO_TBL表:PHOTO_DATA字段用于存放文件,类型为MyBatis的longblob;然后写Mapper的Java接口PhotoMapper:包括增删改查;mapper的xml文件:对应JAVA接口的sql语句。

并且需要Spring配置文件添加一个bean的声明。

下面给出html、action、StudentForm的代码片段;创建PHOTO_TBL表的sql、PhotoMapper.java接口代码、PhotoMapper.xml文件代码。

1.1 html的form表单写法

1.<form action="<c:url value='addAction.do' />" method="post" enctype="multipart/form-data"> 
2. <table> 
3. <tr> 
4. <td width="100" align="right">照片:</td> 
5. <td><input type="file" name="studentPhoto"/></td> 
6. </tr> 
7. </table> 
8. <input type="submit"> 
9.</form> 

1.2 action方法

1./** 
2. * 新增 - 提交 
3. */ 
4.@RequestMapping(value = "addAction.do") 
5.public String add_action(ModelMap model, StudentForm form) { 
6. 
7.} 

1.3 StudentForm类

1.package liming.student.manager.web.model; 
2. 
3.import org.springframework.web.multipart.MultipartFile; 
4. 
5.public class StudentForm extends GeneralForm { 
6. 
7. private String studentName; 
8. private int studentSex; 
9. private String studentBirthday; 
10. private MultipartFile studentPhoto; 
11. 
12.} 

1.4 创建PHOTO_TBL

1.CREATE TABLE PHOTO_TBL 
2.( 
3. PHOTO_ID VARCHAR(100) PRIMARY KEY, 
4. PHOTO_DATA LONGBLOB, 
5. FILE_NAME VARCHAR(10) 
6.); 

1.5 PhotoMapper接口

1.@Repository 
2.@Transactional 
3.public interface PhotoMapper { 
4. 
5. public void createPhoto(PhotoEntity entity); 
6. 
7. public int deletePhotoByPhotoId(String photoId); 
8. 
9. public int updatePhotoDate(@Param("photoId") String photoId, @Param("photoDate") byte[] photoDate); 
10. 
11. public PhotoEntity getPhotoEntityByPhotoId(String photoId); 
12. 
13.} 

1.6 PhotoMapper.xml文件

包括增、删、改、查。其中新增中的photoId使用的是mysql自定义函数自动生成主键。在操作blob时需要制定typeHandler为"org.apache.ibatis.type.BlobTypeHandler。insert、update时参数后面需要指定,resultMap中需要指定。

1.<?xml version="1.0" encoding="UTF-8" ?> 
2.<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd"> 
3.<mapper namespace="liming.student.manager.data.PhotoMapper"> 
4. <resultMap type="liming.student.manager.data.model.PhotoEntity" id="photoMapper_resultMap_photoEntity"> 
5. <id property="photoId" column="PHOTO_ID" javaType="String" jdbcType="VARCHAR" /> 
6. <result property="photoData" column="PHOTO_DATA" javaType="byte[]" jdbcType="BLOB" typeHandler="org.apache.ibatis.type.BlobTypeHandler" /> 
7. <result property="fileName" column="FILE_NAME" javaType="String" jdbcType="VARCHAR" /> 
8. </resultMap> 
9. 
10. <insert id="createPhoto" parameterType="liming.student.manager.data.model.PhotoEntity"> 
11. <selectKey keyProperty="photoId" resultType="String" order="BEFORE"> 
12. select nextval('photo') 
13. </selectKey> 
14. INSERT INTO PHOTO_TBL(PHOTO_ID, 
15. PHOTO_DATA, 
16. FILE_NAME) 
17. VALUES(#{photoId, jdbcType=VARCHAR}, 
18. #{photoData, javaType=byte[], jdbcType=BLOB, typeHandler=org.apache.ibatis.type.BlobTypeHandler}, 
19. #{fileName, jdbcType=VARCHAR}) 
20. </insert> 
21. 
22. <delete id="deletePhotoByPhotoId"> 
23. DELETE FROM PHOTO_TBL 
24. WHERE PHOTO_ID = #{photoId, jdbcType=VARCHAR} 
25. </delete> 
26. 
27. <update id="updatephotoData" > 
28. UPDATE PHOTO_TBL 
29. SET PHOTO_DATA = #{photoData, javaType=byte[], jdbcType=BLOB, typeHandler=org.apache.ibatis.type.BlobTypeHandler}, 
30. FILE_NAME = #{fileName, jdbcType=VARCHAR} 
31. WHERE PHOTO_ID = #{photoId, jdbcType=VARCHAR} 
32. </update> 
33. 
34. <select id="getPhotoEntityByPhotoId" resultMap="photoMapper_resultMap_photoEntity"> 
35. SELECT PHOTO_ID, 
36. PHOTO_DATA, 
37. FILE_NAME 
38. FROM PHOTO_TBL 
39. WHERE PHOTO_ID = #{photoId, jdbcType=VARCHAR} 
40. </select> 
41.</mapper> 

1.7 spring配置文件

需要Spring配置文件添加一个org.springframework.web.multipart.commons.CommonsMultipartResolver的bean的声明。

1.<bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver"> 
2. <property name="maxUploadSize" value="1073741824" /> 
3.</bean> 

2. 将文件到服务器上

1.private static final String uploadFilePath = "d:\\temp_upload_file\\"; 
2. 
3./** 
4. * 新增 - 提交 – 只保存文件到服务器上 
5. */ 
6.@RequestMapping(value = "addAction.do") 
7.public String add_action(ModelMap model, StudentForm form) { 
8.try { 
9. MultipartFile uploadFile = form.getStudentPhoto(); 
10. String filename = uploadFile.getOriginalFilename(); 
11. InputStream is = uploadFile.getInputStream(); 
12. // 如果服务器已经存在和上传文件同名的文件,则输出提示信息 
13. File tempFile = new File(uploadFilePath + filename); 
14. if (tempFile.exists()) { 
15. boolean delResult = tempFile.delete(); 
16. System.out.println("删除已存在的文件:" + delResult); 
17. } 
18. // 开始保存文件到服务器 
19. if (!filename.equals("")) { 
20. FileOutputStream fos = new FileOutputStream(uploadFilePath + filename); 
21. byte[] buffer = new byte[8192]; // 每次读8K字节 
22. int count = 0; 
23. // 开始读取上传文件的字节,并将其输出到服务端的上传文件输出流中 
24. while ((count = is.read(buffer)) > 0) { 
25. fos.write(buffer, 0, count); // 向服务端文件写入字节流 
26. } 
27. fos.close(); // 关闭FileOutputStream对象 
28. is.close(); // InputStream对象 
29. } 
30. } catch (FileNotFoundException e) { 
31. e.printStackTrace(); 
32. } catch (IOException e) { 
33. e.printStackTrace(); 
34. } 
35.} 

3. 将文件上传到数据库中

1./** 
2. * 新增 - 提交 – 保存文件到数据库 
3. */ 
4.@RequestMapping(value = "addAction.do") 
5.public String add_action(ModelMap model, StudentForm form) { 
6. InputStream is = form.getStudentPhoto().getInputStream(); 
7. byte[] studentPhotoData = new byte[(int) form.getStudentPhoto().getSize()]; 
8. is.read(studentPhotoData); 
9. String fileName = form.getStudentPhoto().getOriginalFilename(); 
10. PhotoEntity photoEntity = new PhotoEntity(); 
11. photoEntity.setPhotoData(studentPhotoData); 
12. photoEntity.setFileName(fileName); 
13. this.photoMapper.createPhoto(photoEntity); 
14.} 

4.下载文件

下载文件需要将byte数组还原成文件。

首先使用mybatis将数据库中的byte数组查出来,指定文件名(包括格式)。然后使用OutputStream将文件输入

1.@RequestMapping(value = "downPhotoById") 
2.public void downPhotoByStudentId(String id, final HttpServletResponse response){ 
3. PhotoEntity entity = this.photoMapper.getPhotoEntityByPhotoId(id); 
4. byte[] data = entity.getPhotoData(); 
5. String fileName = entity.getFileName()== null ? "照片.png" : entity.getFileName(); 
6. fileName = URLEncoder.encode(fileName, "UTF-8"); 
7. response.reset(); 
8. response.setHeader("Content-Disposition", "attachment; filename=\"" + fileName + "\""); 
9. response.addHeader("Content-Length", "" + data.length); 
10. response.setContentType("application/octet-stream;charset=UTF-8"); 
11. OutputStream outputStream = new BufferedOutputStream(response.getOutputStream()); 
12. outputStream.write(data); 
13. outputStream.flush(); 
14. outputStream.close(); 
15.} 
<a href="<%=request.getContextPath() %>/downPhotoById.do?id=8000001">下载照片</a> 

5. 显示byte图片文件

1.@RequestMapping(value = "getPhotoById") 
2.public void getPhotoById (String id, final HttpServletResponse response){ 
3. PhotoEntity entity = this.photoMapper.getPhotoEntityByPhotoId(id); 
4. byte[] data = entity.getPhotoData(); 
5. response.setContentType("image/jpeg"); 
6. response.setCharacterEncoding("UTF-8"); 
7. OutputStream outputSream = response.getOutputStream(); 
8. InputStream in = new ByteArrayInputStream(data); 
9. int len = 0; 
10. byte[] buf = new byte[1024]; 
11. while ((len = in.read(buf, 0, 1024)) != -1) { 
12. outputSream.write(buf, 0, len); 
13. } 
14. outputSream.close(); 
15.} 
<img src="<%=request.getContextPath() %>/getPhotoById.do?id=8000001"/> 

6. 按长宽等比例缩放图片

1.@RequestMapping(value = "getPhotoId") 
2.public void getPhotoById (String id, int width, int height, final HttpServletResponse response){ 
3. PhotoEntity entity = this.photoMapper.getPhotoEntityByPhotoId(id); 
4. byte[] data = entity.getPhotoData(); 
5. if (width != 0 && height != 0) { 
6. data = scaleImage(data, width, height); 
7. } 
8. response.setContentType("image/jpeg"); 
9. response.setCharacterEncoding("UTF-8"); 
10. OutputStream outputSream = response.getOutputStream(); 
11. InputStream in = new ByteArrayInputStream(data); 
12. int len = 0; 
13. byte[] buf = new byte[1024]; 
14. while ((len = in.read(buf, 0, 1024)) != -1) { 
15. outputSream.write(buf, 0, len); 
16. } 
17. outputSream.close(); 
18.} 
19. 
20.public static byte[] scaleImage(byte[] data, int width, int height) throws IOException { 
21. BufferedImage buffered_oldImage = ImageIO.read(new ByteArrayInputStream(data)); 
22. int imageOldWidth = buffered_oldImage.getWidth(); 
23. int imageOldHeight = buffered_oldImage.getHeight(); 
24. double scale_x = (double) width / imageOldWidth; 
25. double scale_y = (double) height / imageOldHeight; 
26. double scale_xy = Math.min(scale_x, scale_y); 
27. int imageNewWidth = (int) (imageOldWidth * scale_xy); 
28. int imageNewHeight = (int) (imageOldHeight * scale_xy); 
29. BufferedImage buffered_newImage = new BufferedImage(imageNewWidth, imageNewHeight, BufferedImage.TYPE_INT_RGB); 
30. buffered_newImage.getGraphics().drawImage(buffered_oldImage.getScaledInstance(imageNewWidth, imageNewHeight, BufferedImage.SCALE_SMOOTH), 0, 0, null); 
31. buffered_newImage.getGraphics().dispose(); 
32. ByteArrayOutputStream outPutStream = new ByteArrayOutputStream(); 
33. ImageIO.write(buffered_newImage, "jpeg", outPutStream); 
34. return outPutStream.toByteArray(); 
35.} 
<img src="<%=request.getContextPath() %>/getPhotoById.do?id=8000001&width=300&height=300"/> 

以上所述是小编给大家介绍的MyBatis与SpringMVC相结合实现文件上传、下载功能,希望对大家有所帮助,如果大家有任何疑问请给我留言,小编会及时回复大家的。在此也非常感谢大家对脚本之家网站的支持!

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