myBatis + SpringMVC上传、下载文件

 

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

<form action="<c:url value='addAction.do' />" method="post" enctype="multipart/form-data">		
	<table>
		<tr>
			<td width="100" align="right">照片：</td>
			<td><input type="file" name="studentPhoto"/></td>
		</tr>
	</table>
	<input type="submit">
</form>

 

 

 

1.2 action方法

/**
 * 新增 - 提交
 */
@RequestMapping(value = "addAction.do")
public String add_action(ModelMap model, StudentForm form) {

}

 

 

 

1.3 StudentForm类

package liming.student.manager.web.model;

import org.springframework.web.multipart.MultipartFile;

public class StudentForm extends GeneralForm {

	private String studentName;
	private int studentSex;
	private String studentBirthday;
	private MultipartFile studentPhoto;

}

 

 

 

 

1.4 创建PHOTO_TBL

CREATE TABLE PHOTO_TBL
(
   PHOTO_ID     VARCHAR(100) PRIMARY KEY,
   PHOTO_DATA   LONGBLOB,
   FILE_NAME    VARCHAR(10)
);

 

 

 

1.5  PhotoMapper接口

@Repository
@Transactional
public interface PhotoMapper {

	public void createPhoto(PhotoEntity entity);

	public int deletePhotoByPhotoId(String photoId);

	public int updatePhotoDate(@Param("photoId") String photoId, @Param("photoDate") byte[] photoDate);

	public PhotoEntity getPhotoEntityByPhotoId(String photoId);

}

 

 

 

 

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。

 

<?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="liming.student.manager.data.PhotoMapper">
	<resultMap type="liming.student.manager.data.model.PhotoEntity" id="photoMapper_resultMap_photoEntity">
		<id property="photoId"			column="PHOTO_ID" 		javaType="String" jdbcType="VARCHAR" />
		<result property="photoData"	column="PHOTO_DATA" 	javaType="byte[]" jdbcType="BLOB" typeHandler="org.apache.ibatis.type.BlobTypeHandler" />
		<result property="fileName" 	column="FILE_NAME" 		javaType="String" jdbcType="VARCHAR" />
	</resultMap>
	
	<insert id="createPhoto" parameterType="liming.student.manager.data.model.PhotoEntity">
		<selectKey keyProperty="photoId" resultType="String" order="BEFORE">
			select nextval('photo')
		</selectKey>
		INSERT INTO PHOTO_TBL(PHOTO_ID,
						      PHOTO_DATA,
						      FILE_NAME)
		VALUES(#{photoId, jdbcType=VARCHAR},
			   #{photoData, javaType=byte[], jdbcType=BLOB, typeHandler=org.apache.ibatis.type.BlobTypeHandler},
			   #{fileName, jdbcType=VARCHAR})
	</insert>
	
	<delete id="deletePhotoByPhotoId">
		DELETE FROM PHOTO_TBL
		      WHERE PHOTO_ID = #{photoId, jdbcType=VARCHAR}
	</delete>
	
	<update id="updatephotoData" >
		UPDATE PHOTO_TBL 
		   SET PHOTO_DATA = #{photoData, javaType=byte[], jdbcType=BLOB, typeHandler=org.apache.ibatis.type.BlobTypeHandler},
		       FILE_NAME = #{fileName, jdbcType=VARCHAR}
		 WHERE PHOTO_ID = #{photoId, jdbcType=VARCHAR}
	</update>
		
	<select id="getPhotoEntityByPhotoId" resultMap="photoMapper_resultMap_photoEntity">
		SELECT PHOTO_ID,
		       PHOTO_DATA,
		       FILE_NAME
		  FROM PHOTO_TBL
		 WHERE PHOTO_ID = #{photoId, jdbcType=VARCHAR}
	</select>
</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。

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

 

 

 

2. 将文件到服务器上

private static final String uploadFilePath = "d:\\temp_upload_file\\";

/**
 * 新增 - 提交 – 只保存文件到服务器上
 */
@RequestMapping(value = "addAction.do")
public String add_action(ModelMap model, StudentForm form) {
try {
		MultipartFile uploadFile = form.getStudentPhoto();
		String filename = uploadFile.getOriginalFilename();
		InputStream is = uploadFile.getInputStream();
		// 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
		File tempFile = new File(uploadFilePath + filename);
		if (tempFile.exists()) {
			boolean delResult = tempFile.delete();
			System.out.println("删除已存在的文件：" + delResult);
		}
		// 开始保存文件到服务器
		if (!filename.equals("")) {
			FileOutputStream fos = new FileOutputStream(uploadFilePath + filename);
			byte[] buffer = new byte[8192]; // 每次读8K字节
			int count = 0;
			// 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
			while ((count = is.read(buffer)) > 0) {
				fos.write(buffer, 0, count); // 向服务端文件写入字节流
			}
			fos.close(); // 关闭FileOutputStream对象
			is.close(); // InputStream对象
		}
	} catch (FileNotFoundException e) {
		e.printStackTrace();
	} catch (IOException e) {
		e.printStackTrace();
	}
}

 

 

 

3. 将文件上传到数据库中

/**
 * 新增 - 提交 – 保存文件到数据库
 */
@RequestMapping(value = "addAction.do")
public String add_action(ModelMap model, StudentForm form) {
	InputStream is = form.getStudentPhoto().getInputStream();
	byte[] studentPhotoData = new byte[(int) form.getStudentPhoto().getSize()];
	is.read(studentPhotoData);
	String fileName = form.getStudentPhoto().getOriginalFilename();
	PhotoEntity photoEntity = new PhotoEntity();
	photoEntity.setPhotoData(studentPhotoData);
	photoEntity.setFileName(fileName);
	this.photoMapper.createPhoto(photoEntity);
}

 

 

 

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

 

@RequestMapping(value = "downPhotoById")
public void downPhotoByStudentId(String id, final HttpServletResponse response){
	PhotoEntity entity = this.photoMapper.getPhotoEntityByPhotoId(id);
	byte[] data = entity.getPhotoData();
	String fileName = entity.getFileName()== null ? "照片.png" : entity.getFileName();
	fileName = URLEncoder.encode(fileName, "UTF-8");
	response.reset();
	response.setHeader("Content-Disposition", "attachment; filename=\"" + fileName + "\"");
	response.addHeader("Content-Length", "" + data.length);
	response.setContentType("application/octet-stream;charset=UTF-8");
	OutputStream outputStream = new BufferedOutputStream(response.getOutputStream());
	outputStream.write(data);
	outputStream.flush();
	outputStream.close();
}

 

<a href="<%=request.getContextPath() %>/downPhotoById.do?id=8000001">下载照片</a>

 

 

 

5. 显示byte图片文件

@RequestMapping(value = "getPhotoById")
public void getPhotoById (String id, final HttpServletResponse response){
	PhotoEntity entity = this.photoMapper.getPhotoEntityByPhotoId(id);
	byte[] data = entity.getPhotoData();
	response.setContentType("image/jpeg");
	response.setCharacterEncoding("UTF-8");
	OutputStream outputSream = response.getOutputStream();
	InputStream in = new ByteArrayInputStream(data);
	int len = 0;
	byte[] buf = new byte[1024];
	while ((len = in.read(buf, 0, 1024)) != -1) {
		outputSream.write(buf, 0, len);
	}
	outputSream.close();
}

 

<img src="<%=request.getContextPath() %>/getPhotoById.do?id=8000001"/>

 

 

 

6. 按长宽等比例缩放图片

@RequestMapping(value = "getPhotoId")
public void getPhotoById (String id, int width, int height, final HttpServletResponse response){
	PhotoEntity entity = this.photoMapper.getPhotoEntityByPhotoId(id);
	byte[] data = entity.getPhotoData();
	if (width != 0 && height != 0) {
		data = scaleImage(data, width, height);
	}
	response.setContentType("image/jpeg");
	response.setCharacterEncoding("UTF-8");
	OutputStream outputSream = response.getOutputStream();
	InputStream in = new ByteArrayInputStream(data);
	int len = 0;
	byte[] buf = new byte[1024];
	while ((len = in.read(buf, 0, 1024)) != -1) {
		outputSream.write(buf, 0, len);
	}
	outputSream.close();
}

public static byte[] scaleImage(byte[] data, int width, int height) throws IOException {
	BufferedImage buffered_oldImage = ImageIO.read(new ByteArrayInputStream(data));
	int imageOldWidth = buffered_oldImage.getWidth();
	int imageOldHeight = buffered_oldImage.getHeight();
	double scale_x = (double) width / imageOldWidth;
	double scale_y = (double) height / imageOldHeight;
	double scale_xy = Math.min(scale_x, scale_y);
	int imageNewWidth = (int) (imageOldWidth * scale_xy);
	int imageNewHeight = (int) (imageOldHeight * scale_xy);
	BufferedImage buffered_newImage = new BufferedImage(imageNewWidth, imageNewHeight, BufferedImage.TYPE_INT_RGB);
	buffered_newImage.getGraphics().drawImage(buffered_oldImage.getScaledInstance(imageNewWidth, imageNewHeight, BufferedImage.SCALE_SMOOTH), 0, 0, null);
	buffered_newImage.getGraphics().dispose();
	ByteArrayOutputStream outPutStream = new ByteArrayOutputStream();
	ImageIO.write(buffered_newImage, "jpeg", outPutStream);
	return outPutStream.toByteArray();
}

 

<img src="<%=request.getContextPath() %>/getPhotoById.do?id=8000001&width=300&height=300"/>

 

 

评论

6 楼 zqb666kkk 2013-12-23  

PhotoEntity 呢？

5 楼 zqb666kkk 2013-12-23  

photoEntity.setPhotoData(studentPhotoData); 

你这句话 有问题吧 

实体类里 是   private MultipartFile studentPhoto; 

MultipartFile 类型的
set的时候byte[] 类型
类型不符合 编译都通不过的

4 楼 eye_dxj 2013-10-30  

outputStream.flush();          

3 楼 ddnzero 2013-05-21  

PhotoMapper.xml文件 这个正需要啊 感谢~

2 楼 我是菜鸟1号 2013-03-29  

貌似没看到 PhotoEntity  这个类吧...

1 楼 幸福人生 2011-09-23  

很好，代码直接拷贝就可以，支持一下！