SpringMVC02之CRUD和文件上传下载

末蓝、 2024-04-07 16:11 32阅读 0赞

**目录**

1.CRUD

CRUD是4个单词的首字母，CRUD分别指增加（Create）、读取查询（Retrieve）、更新（Update）和删除（Delete）这4个单词的首字母。

2. springmvc的文件上传

2.1 添加文件上传相关依赖

2.2 配置文件上传解析器(CommonsMultipartResolver)

2.3 表单提交方式为method="post" enctype="multipart/form-data"

2.4 文件项用spring提供的MultipartFile进行接收

2.5 上传文件

2.6 下载文件

3.文件上传三要素

4.代码

--------------------

## 1.CRUD ##

**CRUD是4个单词的首字母，CRUD分别指增加（Create）、读取查询（Retrieve）、更新（Update）和删除（Delete）这4个单词的首字母。**

> **（1）C：Create（增加） 对应 create table table1;**
> 
> **（2）R：Retrieve（查询）对应 select \* from table1;**
> 
> **（3）U：Update（更新） 对应 update table1 set col1=value1 where id=value2;**
> 
> **（4）D：Delete（删除）对应 delete from table1 where id=value1;**

##  2. springmvc的文件上传 ##

**2.1 添加文件上传相关依赖**

<dependency>
         <groupId>commons-fileupload</groupId>
         <artifactId>commons-fileupload</artifactId>
         <version>1.3.3</version>
    </dependency>

**2.2 配置文件上传解析器(CommonsMultipartResolver)**

**2.3 表单提交方式为method="post" enctype="multipart/form-data"**

**2.4 文件项用spring提供的MultipartFile进行接收**

**2.5 上传文件**

>  **注：springmvc文件上传关键代码  
> File targetFile = ....;  
> MultipartFile mf = ....;  
> String fileName = mf.getOriginalFilename();  
> mf.transferTo(targetFile);**

**2.6 下载文件**

@RequestMapping(value="/download")
    public ResponseEntity<byte[]> download(@RequestParam String fileId){
    
       //先根据文件id查询对应图片信息
    
       //下载关键代码
       File file=new File(bookFile.getUrl());
       HttpHeaders headers = new HttpHeaders();//http头信息
       String downloadFileName = new String(fileName.getBytes("UTF-8"),"iso-8859-1");//设置编码
       headers.setContentDispositionFormData("attachment", downloadFileName);
       headers.setContentType(MediaType.APPLICATION_OCTET_STREAM);
       //MediaType:互联网媒介类型  contentType：具体请求中的媒体类型信息
       return new ResponseEntity<byte[]>(FileUtils.readFileToByteArray(file),headers, HttpStatus.OK);
    
    }

## 3.文件上传三要素 ##

> **(1)表单的提交方式必须是POST请求  
> (2)表单中必须有一个文件上传项:<input type=“file” name=“upload”/>，文件上传项必须有name属性和值；  
> (3)表单的enctype属性的值必须是multipart/form-data**

## 4.代码 ##

**下面是数据库表：**

create table t_book_file
    (
      file_id varchar(32) primary key comment '文件ID',
      real_name varchar(50) not null comment '文件名称',
      content_type varchar(50) not null comment '文件类型',
      url varchar(256) not null comment '文件路径'
    );

**下面就是代码了：**

**BookFile.java**

package com.zking.ssm.model;
    
    public class BookFile {
        private String fileId;
        private String realName;
        private String contentType;
        private String url;
    
        public BookFile(String fileId, String realName, String contentType, String url) {
            this.fileId = fileId;
            this.realName = realName;
            this.contentType = contentType;
            this.url = url;
        }
    
        public BookFile() {
            super();
        }
    
        public String getFileId() {
            return fileId;
        }
    
        public void setFileId(String fileId) {
            this.fileId = fileId;
        }
    
        public String getRealName() {
            return realName;
        }
    
        public void setRealName(String realName) {
            this.realName = realName;
        }
    
        public String getContentType() {
            return contentType;
        }
    
        public void setContentType(String contentType) {
            this.contentType = contentType;
        }
    
        public String getUrl() {
            return url;
        }
    
        public void setUrl(String url) {
            this.url = url;
        }
    }

**BookFileMapper.java**

package com.zking.ssm.mapper;
    import com.zking.ssm.model.BookFile;
    import org.springframework.stereotype.Repository;
    
    @Repository
    public interface BookFileMapper {
        int deleteByPrimaryKey(String fileId);
        int insert(BookFile record);
        int insertSelective(BookFile record);
        BookFile selectByPrimaryKey(String fileId);
        int updateByPrimaryKeySelective(BookFile record);
        int updateByPrimaryKey(BookFile record);
    }

**BookFileVo**

package com.zking.ssm.vo;
    import com.zking.ssm.model.BookFile;
    import lombok.Data;
    import org.springframework.web.multipart.MultipartFile;
    
    @Data
    public class BookFileVo extends BookFile {
        //书本ID
        private Integer bookId;
        //文件对象
        private MultipartFile bFile;
    }

**IBookFileService**

package com.zking.ssm.service;
    import com.zking.ssm.model.BookFile;
    import com.zking.ssm.vo.BookFileVo;
    import org.springframework.stereotype.Repository;
    
    public interface IBookFileService {
        int addBookFile(BookFileVo bookFileVo);
        BookFile selectOne(String fileId);
    }

**BookFileServiceImpl**

package com.zking.ssm.service.impl;
    import com.zking.ssm.mapper.BookFileMapper;
    import com.zking.ssm.mapper.BookMapper;
    import com.zking.ssm.model.Book;
    import com.zking.ssm.model.BookFile;
    import com.zking.ssm.service.IBookFileService;
    import com.zking.ssm.vo.BookFileVo;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.stereotype.Service;
    import org.springframework.transaction.annotation.Transactional;
    import java.util.UUID;
    
    @Service
    public class BookFileServiceImpl implements IBookFileService {
    
        @Autowired
        private BookFileMapper bookFileMapper;
    
        @Autowired
        private BookMapper bookMapper;
    
        @Transactional
        @Override
        public int addBookFile(BookFileVo bookFileVo) {
        //生成上传图片的FileID
        String fileID= UUID.randomUUID().toString().replace("-","");
        //新增书本图片信息t_book_file
        bookFileVo.setFileId(fileID);
        bookFileMapper.insert(bookFileVo);
        //根据书本ID修改书本的Book_image
        Book book=new Book();
        book.setBookId(bookFileVo.getBookId());
        book.setBookImage(fileID);
        bookMapper.updateBookImageById(book);
            return 1;
        }
    
        @Override
        public BookFile selectOne(String fileId) {
            return bookFileMapper.selectByPrimaryKey(fileId);
        }
    }

**BookFileController**

package com.zking.ssm.controller;
    import com.zking.ssm.model.BookFile;
    import com.zking.ssm.service.IBookFileService;
    import com.zking.ssm.service.IBookService;
    import com.zking.ssm.vo.BookFileVo;
    import org.apache.commons.io.FileUtils;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.http.HttpHeaders;
    import org.springframework.http.HttpStatus;
    import org.springframework.http.MediaType;
    import org.springframework.http.ResponseEntity;
    import org.springframework.stereotype.Controller;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RequestParam;
    import org.springframework.web.multipart.MultipartFile;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import java.io.File;
    import java.io.IOException;
    
    @Controller
    @RequestMapping("/bookFile")
    public class BookFileController {
    
        public static final String DETAIL_PATH="D:/Y1/SSM/ssm/target/ssm/uploads/";
    
        @Autowired
        private IBookService bookService;
        
        @Autowired
        private IBookFileService bookFileService;
    
        //文件上传与下载宗旨：文件从哪里来，放哪里去！！！
        /**
         * 上传：文件从客户端来，上传服务器指定位置
         */
        @RequestMapping("/upload")
        public String upload(BookFileVo bookFileVo, HttpServletRequest req){
            try {
                MultipartFile bFile = bookFileVo.getBFile();
                //图片保存路径（相对路径），例如：/uploads/1.jpg
                String filePath=DETAIL_PATH+bFile.getOriginalFilename();
                //将相对路径转换成绝对路径，例如：D:/uploads/1.jpg
                String absolutePath = this.transfor(req, filePath);
                //思路：
                //1.将客户端的图片保存到服务器上指定的位置
                bFile.transferTo(new File(absolutePath));
    
                //2.在t_book_file表添加一条图片记录信息
                //3.根据书本ID更新书本信息表中的book_image
                bookFileVo.setRealName(bFile.getOriginalFilename());
                bookFileVo.setContentType(bFile.getContentType());
                bookFileVo.setUrl(filePath);
                bookFileService.addBookFile(bookFileVo);
            } catch (Exception e) {
                e.printStackTrace();
            }
            return "redirect:/book/qureyBookPager";
        }
    
        /**
         * 下载：将服务器上指定的文件下载到客户端中
         */
        @RequestMapping(value="/download")
        public ResponseEntity<byte[]> download(HttpServletRequest req,@RequestParam String fileId){
    
            try {
                //先根据文件id查询对应图片信息
                BookFile bookFile = bookFileService.selectOne(fileId);
                //将相对路径转换成绝对路径
                String filePath=this.transfor(req,bookFile.getUrl());
                //下载关键代码
                File file=new File(filePath);
                HttpHeaders headers = new HttpHeaders();//http头信息
                String downloadFileName = new String(bookFile.getRealName().getBytes("UTF-8"),"iso-8859-1");//设置编码
                headers.setContentDispositionFormData("attachment", downloadFileName);
                headers.setContentType(MediaType.APPLICATION_OCTET_STREAM);
                //MediaType:互联网媒介类型  contentType：具体请求中的媒体类型信息
                return new ResponseEntity<byte[]>(FileUtils.readFileToByteArray(file),headers, HttpStatus.OK);
            } catch (Exception e) {
                e.printStackTrace();
            }
    return null;
        }
    
        /**
         * 将相对路径转换成绝对路径
         * @param req
         * @param relativePath
         * @return
         */
        private String transfor(HttpServletRequest req,String relativePath){
            return req.getServletContext().getRealPath(relativePath);
        }
    }

**index.jsp**

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
    <%@taglib prefix="shiro" uri="http://shiro.apache.org/tags" %>
    <html>
    <head>
        <%@include file="/common/head.jsp"%>
    </head>
    <>
    <h1>Hello SpringMvc!!!</h1><br>
    <div style="position: absolute;top: 10px;right: 10px"><a onclick="return confirm('确定退出吗')" href="${ctx}/user/logout">安全退出</a></div>
    <shiro:hasRole name="管理员">
        <a href="${ctx}/book/toBookList">跳转到书本列表页</a>
        <a href="${ctx}/page/book/addBook">跳转到书本新增页</a><br/>
    </shiro:hasRole>
    </body>
    </html>

**bookList.jsp**

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
    <%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
    <html>
    <head>
       <%@include file="/common/head.jsp"%>
    </head>
    <body>
    <h1>书本列表</h1>
    <form action="${ctx}/book/qureyBookPager" method="post">
       <label>书本名称：</label> <input type="text" name="bookName"/>
       <input type="submit" value="查询">
    </form>
    <a href="${ctx}/page/book/addBook">书本新增</a>
    <table width="100%" border="1" cellspacing="0" cellpadding="0">
       <tr>
          <th>书本编号</th>
          <th>书本名称</th>
          <th>书本图片</th>
          <th>书本价格</th>
          <th>书本类型</th>
          <th>操作</th>
       </tr>
       <c:forEach items="${books}" var="b">
          <tr>
             <td>${b.bookId}</td>
             <td>${b.bookName}</td>
             <td>
                <c:if test="${empty b.bookImage}">
                   未上传图片
                </c:if>
                <c:if test="${not empty b.bookImage}">
                   <img src="${ctx}/bookFile/download?fileId=${b.bookImage}" width="150px"/>
                </c:if>
             </td>
             <td>${b.bookPrice}</td>
             <td>${b.bookType}</td>
             <td>
                <a href="${ctx}/book/getOne?bookId=${b.bookId}&type=detail">详情</a>
                <a href="${ctx}/book/getOne?bookId=${b.bookId}&type=edit">编辑</a>
                <a onclick="return confirm('确认删除？');" href="${ctx}/book/delBook?bookId=${b.bookId}">删除</a>
                <c:if test="${empty b.bookImage}">
                   <a href="${ctx}/page/book/uploadBook?bookId=${b.bookId}">文件上传</a>
                </c:if>
                <c:if test="${not empty b.bookImage}">
                   <a href="${ctx}/bookFile/download?fileId=${b.bookImage}">文件下载</a>
                </c:if>
             </td>
          </tr>
       </c:forEach>
    </table>
    ${pageBean}
    </body>
    </html>

**我就没有把所有的代码放上来了，其他的增删改页面和我之前那些差不多，相信大家也都会了，下面是那个界面图，很简洁的一个页面，也就是i给大家做个示例，所以不要太纠结哈，功能能用就行哈！！！**

![d208681725e04379b4508da66260c9f6.png][]

###  以上就是今天要讲的CRUD和文件上传下载，谢谢赏读！！！ ###

### ![900c5365051b47e8855534caa8c624b0.gif][] ###

[d208681725e04379b4508da66260c9f6.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/07/aec0387e389e4896a5a14571809df765.png
[900c5365051b47e8855534caa8c624b0.gif]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/07/5f975517b5d84030bab339653511273a.gif