Java（二）：Spring Boot 项目-文件的增删改查下载

Spring Boot 项目-文件的增删改查下载

- 准备
- - docker运行mysql
  - 设置MySQL时区
  - 查看当前MySQL使用的时区
  - MySQL建库建表
- 定义两个实体类
- - 数据表实体类
  - 查询条件实体类
- 工具类
- - `com/example/user/utils/FileUtil.java`
- 用到的SQL语句
- - mapper `user/src/main/resources/mapper/FileTableDao.xml`
- 增/改(上传)
- - controller `com/example/user/controller/FileTableController.java`
  - service `com/example/user/service/impl/FileTableServiceImpl.java`
- 删
- - controller `com/example/user/controller/FileTableController.java`
  - service `com/example/user/service/impl/FileTableServiceImpl.java`
- 查
- - controller `com/example/user/controller/FileTableController.java`
  - service `com/example/user/service/impl/FileTableServiceImpl.java`
- 下载
- - controller `com/example/user/controller/FileTableController.java`
  - service `com/example/user/service/impl/FileTableServiceImpl.java`
- 完整源码
- - 目录结构
  - 源码

准备

docker运行mysql

$ docker run --name local-mysql -p 3306:3306 -v /Users/lee/Documents/AAA-PLee/C-Code/mysql/conf.d:/etc/mysql/conf.d -e MYSQL_ROOT_PASSWORD=123456 -d mysql

设置MySQL时区

添加修改 /mysql/conf.d/xxx.cnf 文件，并重启 MySQL

[mysqld]

default-time_zone = '+8:00'

查看当前MySQL使用的时区

SELECT @@global.time_zone; # +08:00

MySQL建库建表

create database java_app;

create table java_app.file_table
(
    id         varchar(255)                     not null primary key, -- 文件ID
    name       varchar(255)                     not null,             -- 文件真实名称
    extension  varchar(10)                      null,                 -- 文件扩展名
    type       varchar(255)                     null,                 -- 文件类型
    size       int                              not null,             -- 文件大小（单位：字节）
    status     int          default 1           not null,             -- 文件当前状态（0删除，1存在）
    createTime datetime     default NOW()       not null,             -- 文件创建时间
    updateTime datetime                         null                  -- 文件修改时间
);

定义两个实体类

数据表实体类

注意：规定参数时区

com/example/user/entity/FileTable.java

package com.example.user.entity;

import com.fasterxml.jackson.annotation.JsonFormat;

import java.util.Date;
import java.io.Serializable;

/**
 * (FileTable)实体类
 */
public class FileTable implements Serializable {

    private String id;

    private String name;

    private String extension;

    private String type;

    private Integer size;

    private Integer status;

    @JsonFormat(timezone = "GMT+8", pattern = "yyyy-MM-dd HH:mm:ss")
    private Date createTime;

    @JsonFormat(timezone = "GMT+8", pattern = "yyyy-MM-dd HH:mm:ss")
    private Date updateTime;


    public FileTable(String id, String name, String extension, String type, Integer size) {
        this.id = id;
        this.name = name;
        this.extension = extension;
        this.type = type;
        this.size = size;
    }

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getExtension() {
        return extension;
    }

    public void setExtension(String extension) {
        this.extension = extension;
    }

    public String getType() {
        return type;
    }

    public void setType(String type) {
        this.type = type;
    }

    public Integer getSize() {
        return size;
    }

    public void setSize(Integer size) {
        this.size = size;
    }

    public Integer getStatus() {
        return status;
    }

    public void setStatus(Integer status) {
        this.status = status;
    }

    public Date getCreateTime() {
        return createTime;
    }

    public void setCreateTime(Date createTime) {
        this.createTime = createTime;
    }

    public Date getUpdateTime() {
        return updateTime;
    }

    public void setUpdateTime(Date updateTime) {
        this.updateTime = updateTime;
    }

}

查询条件实体类

com/example/user/entity/FileTableCondition.java

package com.example.user.entity;

import java.io.Serializable;
import java.util.Date;

/**
 * 查询条件
 */
public class FileTableCondition implements Serializable {

    private String id;

    private String name;

    private String extension;

    private String type;

    private Integer minSize;

    private Integer maxSize;

    private Integer status;

    private Date startCreateTime;

    private Date endCreateTime;

    private Date startUpdateTime;

    private Date endUpdateTime;

    public FileTableCondition(
            String id, String name, String extension, String type,
            Integer status,
            Integer minSize, Integer maxSize,
            Date startCreateTime, Date endCreateTime,
            Date startUpdateTime, Date endUpdateTime
    ) {
        this.id = id;
        this.name = name;
        this.extension = extension;
        this.type = type;
        this.status = status;
        this.minSize = minSize;
        this.maxSize = maxSize;
        this.startCreateTime = startCreateTime;
        this.endCreateTime = endCreateTime;
        this.startUpdateTime = startUpdateTime;
        this.endUpdateTime = endUpdateTime;
    }
}

工具类

`com/example/user/utils/FileUtil.java`

package com.example.user.utils;

import com.example.user.entity.FileTable;
import org.springframework.core.io.FileSystemResource;
import org.springframework.http.HttpHeaders;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.web.multipart.MultipartFile;

import java.io.File;
import java.io.IOException;
import java.util.UUID;

/**
 * 文件工具类
 */
public class FileUtil {

    // 文件保存路径
    private static final String FILE_PATH = "/Users/lee/Documents/AAA-PLee/C-Code/java-app/UploadFiles/";

    /**
     * 保存文件
     *
     * @param fileId        文件ID
     * @param multipartFile 文件
     * @return 文件信息
     * @throws IOException 错误信息
     */
    public static FileTable saveFile(String fileId, MultipartFile multipartFile) throws IOException {
        // 文件完整名称
        String originalFilename = multipartFile.getOriginalFilename();
        // 断言文件名不为空
        assert originalFilename != null;

        // 随机ID作为文件名
        String id = null == fileId || fileId.isEmpty() ? UUID.randomUUID().toString() : fileId;
        // 文件名
        String name = originalFilename.substring(0, originalFilename.lastIndexOf("."));
        // 文件扩展名
        String extension = originalFilename.substring(originalFilename.lastIndexOf(".") + 1);
        // 文件类型
        String type = multipartFile.getContentType();
        // 文件大小（单位：字节）
        int size = (int) multipartFile.getSize();

        // 目标存储位置
        String path = FILE_PATH + id;
        // 把上传的文件转存到目标目录
        multipartFile.transferTo(new File(path));

        // 实例化文件信息
        return new FileTable(id, name, extension, type, size);
    }

    /**
     * 下载文件
     *
     * @param fileTable 实例对象
     * @return 文件流
     */
    public static ResponseEntity<FileSystemResource> downloadFile(FileTable fileTable) {
        File file = new File(FILE_PATH + fileTable.getId());
        FileSystemResource fileSystemResource = new FileSystemResource(file);

        String fileName = fileTable.getName() + "." + fileTable.getExtension();
        HttpHeaders headers = new HttpHeaders();
        headers.add("Content-Disposition", "attachment; filename=" + fileName);
        headers.add("Pragma", "no-cache");
        headers.add("Cache-Control", "no-cache");
        headers.add("Expires", "0");

        return ResponseEntity
                .ok()
                .headers(headers)
                .contentLength(file.length())
                .contentType(MediaType.parseMediaType(fileTable.getType()))
                .body(fileSystemResource);
    }

}

用到的SQL语句

mapper `user/src/main/resources/mapper/FileTableDao.xml`

注意：Integer和int区别

<?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.example.user.dao.FileTableDao">

    <resultMap type="com.example.user.entity.FileTable" id="FileTableMap">
        <result property="id" column="id" jdbcType="VARCHAR"/>
        <result property="name" column="name" jdbcType="VARCHAR"/>
        <result property="extension" column="extension" jdbcType="VARCHAR"/>
        <result property="type" column="type" jdbcType="VARCHAR"/>
        <result property="size" column="size" jdbcType="INTEGER"/>
        <result property="status" column="status" jdbcType="INTEGER"/>
        <result property="createTime" column="createTime" jdbcType="TIMESTAMP"/>
        <result property="updateTime" column="updateTime" jdbcType="TIMESTAMP"/>
    </resultMap>

    <!--新增一条数据-->
    <insert id="insert" keyProperty="" useGeneratedKeys="true">
        insert into file_table(id, name, extension, type, size)
        values (#{id}, #{name}, #{extension}, #{type}, #{size})
    </insert>

    <!--新增多条数据-->
    <insert id="insertList" parameterType="java.util.List">
        insert into file_table(id, name, extension, type, size)
        values
        <foreach collection="list" item="item" index="index" separator=",">
            (#{item.id}, #{item.name}, #{item.extension}, #{item.type}, #{item.size})
        </foreach>
    </insert>

    <!--通过文件ID删除-->
    <delete id="deleteById">
        update file_table set status = 0, updateTime = NOW() where id = #{id}
    </delete>

    <!--通过文件ID修改数据-->
    <update id="update">
        update file_table
        <set>
            updateTime = NOW(),
            <if test="name != null and name != ''">
                name = #{name},
            </if>
            <if test="extension != null and extension != ''">
                extension = #{extension},
            </if>
            <if test="type != null and type != ''">
                type = #{type},
            </if>
            <if test="size != null and size != ''">
                size = #{size},
            </if>
            <if test="status != null and status != ''">
                status = #{status}
            </if>
        </set>
        where id = #{id}
    </update>

    <!--根据ID查询数据-->
    <select id="queryById" resultMap="FileTableMap">
        select * from file_table
        <where>
            id = #{id}
        </where>
    </select>

    <!--根据ID查询数据-->
    <select id="queryByIds" resultMap="FileTableMap">
        select * from file_table
        <where>
            <foreach collection="list" item="id" index="index">
                <if test="id != null and id != ''">
                    or id = #{id}
                </if>
            </foreach>
        </where>
    </select>

    <!--条件查询数据-->
    <select id="queryByCondition" resultMap="FileTableMap">
        select * from file_table
        <where>
            <if test="id != null and id != ''">
                and id = #{id}
            </if>
            <if test="name != null and name != ''">
                and name = #{name}
            </if>
            <if test="extension != null and extension != ''">
                and extension = #{extension}
            </if>
            <if test="type != null and type != ''">
                and type = #{type}
            </if>
            <if test="status != null">
                and status = #{status}
            </if>
            <if test="minSize != null">
                and size <![CDATA[ >= ]]> #{minSize}
            </if>
            <if test="maxSize != null">
                and size <![CDATA[ <= ]]> #{maxSize}
            </if>
            <if test="startCreateTime != null">
                and DATE_FORMAT(createTime, '%Y-%m-%d') <![CDATA[ >= ]]> DATE_FORMAT(#{startCreateTime}, '%Y-%m-%d')
            </if>
            <if test="endCreateTime != null">
                and DATE_FORMAT(createTime, '%Y-%m-%d') <![CDATA[ <= ]]> DATE_FORMAT(#{endCreateTime}, '%Y-%m-%d')
            </if>
            <if test="startUpdateTime != null">
                and DATE_FORMAT(updateTime, '%Y-%m-%d') <![CDATA[ >= ]]> DATE_FORMAT(#{startUpdateTime}, '%Y-%m-%d')
            </if>
            <if test="endUpdateTime != null">
                and DATE_FORMAT(updateTime, '%Y-%m-%d') <![CDATA[ <= ]]> DATE_FORMAT(#{endUpdateTime}, '%Y-%m-%d')
            </if>
        </where>
    </select>

</mapper>

增/改(上传)

controller `com/example/user/controller/FileTableController.java`

package com.example.user.controller;

import com.example.user.entity.FileTable;
import com.example.user.entity.FileTableCondition;
import com.example.user.service.FileTableService;
import org.springframework.core.io.FileSystemResource;
import org.springframework.format.annotation.DateTimeFormat;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.multipart.MultipartFile;

import javax.annotation.Resource;
import java.io.IOException;
import java.util.Date;
import java.util.List;

/**
 * (FileTable)表控制层
 */
@RestController
@RequestMapping("fileTable")
public class FileTableController {

    /**
     * 服务对象
     */
    @Resource
    private FileTableService fileTableService;

    /**
     * 单/多文件上传 (新增/编辑)
     *
     * @param id             文件ID
     * @param multipartFiles 文件
     * @return 文件信息
     */
    @PostMapping("/upload")
    public ResponseEntity<Object> upload(String id, @RequestParam("file") MultipartFile[] multipartFiles) throws IOException {
        if (null != id && !id.isEmpty() && multipartFiles.length > 0) {
            return ResponseEntity.ok(this.fileTableService.upload(id, multipartFiles[0]));
        } else {
            if (multipartFiles.length > 1) {
                return ResponseEntity.ok(this.fileTableService.upload("", multipartFiles));
            } else {
                return ResponseEntity.ok(this.fileTableService.upload("", multipartFiles[0]));
            }
        }
    }
}

service `com/example/user/service/impl/FileTableServiceImpl.java`

package com.example.user.service.impl;

import com.example.user.dao.FileTableDao;
import com.example.user.entity.FileTable;
import com.example.user.entity.FileTableCondition;
import com.example.user.service.FileTableService;
import com.example.user.utils.FileUtil;
import org.springframework.core.io.FileSystemResource;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Service;
import org.springframework.web.multipart.MultipartFile;

import javax.annotation.Resource;
import java.io.IOException;
import java.util.*;
import java.util.stream.Collectors;

/**
 * (FileTable)表服务实现类
 */
@Service("filesService")
public class FileTableServiceImpl implements FileTableService {

    @Resource
    private FileTableDao fileTableDao;

    /**
     * 单文件上传
     *
     * @param id            文件ID
     * @param multipartFile 文件
     * @return 文件信息
     */
    @Override
    public FileTable upload(String id, MultipartFile multipartFile) throws IOException {
        if (null == id || id.isEmpty()) {
            FileTable fileTable = FileUtil.saveFile("", multipartFile);
            this.fileTableDao.insert(fileTable);
            return this.fileTableDao.queryById(fileTable.getId());
        } else {
            FileTable fileTable = FileUtil.saveFile(id, multipartFile);
            this.fileTableDao.update(fileTable);
            return this.fileTableDao.queryById(fileTable.getId());
        }
    }

    /**
     * 多文件上传
     *
     * @param id             文件ID
     * @param multipartFiles 文件
     * @return 文件信息
     */
    @Override
    public List<FileTable> upload(String id, MultipartFile[] multipartFiles) throws IOException {
        List<FileTable> fileList = new ArrayList<>();
        for (MultipartFile multipartFile : multipartFiles) {
            fileList.add(FileUtil.saveFile("", multipartFile));
        }
        this.fileTableDao.insertList(fileList);
        List<String> ids = fileList.stream().map(FileTable::getId).collect(Collectors.toList());
        return this.fileTableDao.queryByIds(ids);
    }

}

删

controller `com/example/user/controller/FileTableController.java`

package com.example.user.controller;

import com.example.user.entity.FileTable;
import com.example.user.entity.FileTableCondition;
import com.example.user.service.FileTableService;
import org.springframework.core.io.FileSystemResource;
import org.springframework.format.annotation.DateTimeFormat;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.multipart.MultipartFile;

import javax.annotation.Resource;
import java.io.IOException;
import java.util.Date;
import java.util.List;

/**
 * (FileTable)表控制层
 */
@RestController
@RequestMapping("fileTable")
public class FileTableController {

    /**
     * 服务对象
     */
    @Resource
    private FileTableService fileTableService;

    /**
     * 删除数据
     *
     * @param id 文件ID
     * @return 删除是否成功
     */
    @DeleteMapping("{id}")
    public ResponseEntity<Boolean> deleteById(@PathVariable("id") String id) {
        return ResponseEntity.ok(this.fileTableService.deleteById(id));
    }

}

service `com/example/user/service/impl/FileTableServiceImpl.java`

package com.example.user.service.impl;

import com.example.user.dao.FileTableDao;
import com.example.user.entity.FileTable;
import com.example.user.entity.FileTableCondition;
import com.example.user.service.FileTableService;
import com.example.user.utils.FileUtil;
import org.springframework.core.io.FileSystemResource;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Service;
import org.springframework.web.multipart.MultipartFile;

import javax.annotation.Resource;
import java.io.IOException;
import java.util.*;
import java.util.stream.Collectors;

/**
 * (FileTable)表服务实现类
 */
@Service("filesService")
public class FileTableServiceImpl implements FileTableService {

    @Resource
    private FileTableDao fileTableDao;

    /**
     * 通过文件ID删除数据
     *
     * @param id 文件ID
     * @return 是否成功
     */
    @Override
    public boolean deleteById(String id) {
        return this.fileTableDao.deleteById(id) > 0;
    }

}

查

controller `com/example/user/controller/FileTableController.java`

注意：时间格式

package com.example.user.controller;

import com.example.user.entity.FileTable;
import com.example.user.entity.FileTableCondition;
import com.example.user.service.FileTableService;
import org.springframework.core.io.FileSystemResource;
import org.springframework.format.annotation.DateTimeFormat;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.multipart.MultipartFile;

import javax.annotation.Resource;
import java.io.IOException;
import java.util.Date;
import java.util.List;

/**
 * (FileTable)表控制层
 */
@RestController
@RequestMapping("fileTable")
public class FileTableController {

    /**
     * 服务对象
     */
    @Resource
    private FileTableService fileTableService;

    /**
     * 条件查询
     *
     * @param id              文件ID
     * @param name            文件真实名称
     * @param extension       文件扩展名
     * @param type            文件类型
     * @param minSize         最小文件大小（单位：字节）
     * @param maxSize         最大文件大小（单位：字节）
     * @param status          文件当前状态（0删除，1存在）
     * @param startCreateTime 文件创建开始时间
     * @param endCreateTime   文件创建结束时间
     * @param startUpdateTime 文件修改开始时间
     * @param endUpdateTime   文件修改结束时间
     * @return 文件信息
     */
    @GetMapping
    public ResponseEntity<List<FileTable>> queryByCondition(
            @RequestParam(required = false) String id,
            @RequestParam(required = false) String name,
            @RequestParam(required = false) String extension,
            @RequestParam(required = false) String type,
            @RequestParam(required = false) Integer status,
            @RequestParam(required = false) Integer minSize,
            @RequestParam(required = false) Integer maxSize,
            @RequestParam(required = false) @DateTimeFormat(pattern = "yyyy-MM-dd HH:mm:ss") Date startCreateTime,
            @RequestParam(required = false) @DateTimeFormat(pattern = "yyyy-MM-dd HH:mm:ss") Date endCreateTime,
            @RequestParam(required = false) @DateTimeFormat(pattern = "yyyy-MM-dd HH:mm:ss") Date startUpdateTime,
            @RequestParam(required = false) @DateTimeFormat(pattern = "yyyy-MM-dd HH:mm:ss") Date endUpdateTime
    ) {
        FileTableCondition fileTableCondition = new FileTableCondition(
                id, name, extension, type,
                status,
                minSize, maxSize,
                startCreateTime, endCreateTime,
                startUpdateTime, endUpdateTime
        );
        return ResponseEntity.ok(this.fileTableService.queryByCondition(fileTableCondition));
    }

}

service `com/example/user/service/impl/FileTableServiceImpl.java`

package com.example.user.service.impl;

import com.example.user.dao.FileTableDao;
import com.example.user.entity.FileTable;
import com.example.user.entity.FileTableCondition;
import com.example.user.service.FileTableService;
import com.example.user.utils.FileUtil;
import org.springframework.core.io.FileSystemResource;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Service;
import org.springframework.web.multipart.MultipartFile;

import javax.annotation.Resource;
import java.io.IOException;
import java.util.*;
import java.util.stream.Collectors;

/**
 * (FileTable)表服务实现类
 */
@Service("filesService")
public class FileTableServiceImpl implements FileTableService {

    @Resource
    private FileTableDao fileTableDao;

    /**
     * 条件查询
     *
     * @param fileTableCondition 实例对象
     * @return 文件信息
     */
    @Override
    public List<FileTable> queryByCondition(FileTableCondition fileTableCondition) {
        return this.fileTableDao.queryByCondition(fileTableCondition);
    }

}

下载

controller `com/example/user/controller/FileTableController.java`

package com.example.user.controller;

import com.example.user.entity.FileTable;
import com.example.user.entity.FileTableCondition;
import com.example.user.service.FileTableService;
import org.springframework.core.io.FileSystemResource;
import org.springframework.format.annotation.DateTimeFormat;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.multipart.MultipartFile;

import javax.annotation.Resource;
import java.io.IOException;
import java.util.Date;
import java.util.List;

/**
 * (FileTable)表控制层
 */
@RestController
@RequestMapping("fileTable")
public class FileTableController {

    /**
     * 服务对象
     */
    @Resource
    private FileTableService fileTableService;

    @GetMapping("/download/{id}")
    public ResponseEntity<FileSystemResource> download(@PathVariable("id") String id){
        return this.fileTableService.downloadById(id);
    }

}

service `com/example/user/service/impl/FileTableServiceImpl.java`

package com.example.user.service.impl;

import com.example.user.dao.FileTableDao;
import com.example.user.entity.FileTable;
import com.example.user.entity.FileTableCondition;
import com.example.user.service.FileTableService;
import com.example.user.utils.FileUtil;
import org.springframework.core.io.FileSystemResource;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Service;
import org.springframework.web.multipart.MultipartFile;

import javax.annotation.Resource;
import java.io.IOException;
import java.util.*;
import java.util.stream.Collectors;

/**
 * (FileTable)表服务实现类
 */
@Service("filesService")
public class FileTableServiceImpl implements FileTableService {

    @Resource
    private FileTableDao fileTableDao;

    /**
     * 文件下载
     *
     * @param id 文件ID
     * @return 文件流
     */
    @Override
    public ResponseEntity<FileSystemResource> downloadById(String id) {
        FileTable fileTable = this.fileTableDao.queryById(id);
        return FileUtil.downloadFile(fileTable);
    }
}

完整源码

目录结构

在这里插入图片描述

源码

user/src/main/resources/application.yml

server:
  port: 8000

spring:
  application:
    name: user-service
  datasource:
    url: jdbc:mysql://127.0.0.1:3306/java_app
    username: root
    password: 123456
    driver-class-name: com.mysql.cj.jdbc.Driver

mybatis:
  mapper-locations: classpath:**/mapper/*.xml

com/example/user/UserApplication.java

package com.example.user;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.mybatis.spring.annotation.MapperScan;

@SpringBootApplication
@MapperScan(basePackages = "com.example.user.dao")
public class UserApplication {

    public static void main(String[] args) {
        SpringApplication.run(UserApplication.class, args);
    }

}

com/example/user/controller/FileTableController.java

package com.example.user.controller;

import com.example.user.entity.FileTable;
import com.example.user.entity.FileTableCondition;
import com.example.user.service.FileTableService;
import org.springframework.core.io.FileSystemResource;
import org.springframework.format.annotation.DateTimeFormat;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.multipart.MultipartFile;

import javax.annotation.Resource;
import java.io.IOException;
import java.util.Date;
import java.util.List;

/**
 * (FileTable)表控制层
 */
@RestController
@RequestMapping("fileTable")
public class FileTableController {

    /**
     * 服务对象
     */
    @Resource
    private FileTableService fileTableService;

    /**
     * 单/多文件上传 (新增/编辑)
     *
     * @param id             文件ID
     * @param multipartFiles 文件
     * @return 文件信息
     */
    @PostMapping("/upload")
    public ResponseEntity<Object> upload(String id, @RequestParam("file") MultipartFile[] multipartFiles) throws IOException {
        if (null != id && !id.isEmpty() && multipartFiles.length > 0) {
            return ResponseEntity.ok(this.fileTableService.upload(id, multipartFiles[0]));
        } else {
            if (multipartFiles.length > 1) {
                return ResponseEntity.ok(this.fileTableService.upload("", multipartFiles));
            } else {
                return ResponseEntity.ok(this.fileTableService.upload("", multipartFiles[0]));
            }
        }
    }

    /**
     * 删除数据
     *
     * @param id 文件ID
     * @return 删除是否成功
     */
    @DeleteMapping("{id}")
    public ResponseEntity<Boolean> deleteById(@PathVariable("id") String id) {
        return ResponseEntity.ok(this.fileTableService.deleteById(id));
    }

    /**
     * 条件查询
     *
     * @param id              文件ID
     * @param name            文件真实名称
     * @param extension       文件扩展名
     * @param type            文件类型
     * @param minSize         最小文件大小（单位：字节）
     * @param maxSize         最大文件大小（单位：字节）
     * @param status          文件当前状态（0删除，1存在）
     * @param startCreateTime 文件创建开始时间
     * @param endCreateTime   文件创建结束时间
     * @param startUpdateTime 文件修改开始时间
     * @param endUpdateTime   文件修改结束时间
     * @return 文件信息
     */
    @GetMapping
    public ResponseEntity<List<FileTable>> queryByCondition(
            @RequestParam(required = false) String id,
            @RequestParam(required = false) String name,
            @RequestParam(required = false) String extension,
            @RequestParam(required = false) String type,
            @RequestParam(required = false) Integer status,
            @RequestParam(required = false) Integer minSize,
            @RequestParam(required = false) Integer maxSize,
            @RequestParam(required = false) @DateTimeFormat(pattern = "yyyy-MM-dd HH:mm:ss") Date startCreateTime,
            @RequestParam(required = false) @DateTimeFormat(pattern = "yyyy-MM-dd HH:mm:ss") Date endCreateTime,
            @RequestParam(required = false) @DateTimeFormat(pattern = "yyyy-MM-dd HH:mm:ss") Date startUpdateTime,
            @RequestParam(required = false) @DateTimeFormat(pattern = "yyyy-MM-dd HH:mm:ss") Date endUpdateTime
    ) {
        FileTableCondition fileTableCondition = new FileTableCondition(
                id, name, extension, type,
                status,
                minSize, maxSize,
                startCreateTime, endCreateTime,
                startUpdateTime, endUpdateTime
        );
        return ResponseEntity.ok(this.fileTableService.queryByCondition(fileTableCondition));
    }

    @GetMapping("/download/{id}")
    public ResponseEntity<FileSystemResource> download(@PathVariable("id") String id){
        return this.fileTableService.downloadById(id);
    }

}

com/example/user/service/FileTableService.java

package com.example.user.service;

import com.example.user.entity.FileTable;
import com.example.user.entity.FileTableCondition;
import org.springframework.core.io.FileSystemResource;
import org.springframework.http.ResponseEntity;
import org.springframework.web.multipart.MultipartFile;

import java.io.IOException;
import java.util.List;

/**
 * (FileTable)表服务接口
 */
public interface FileTableService {

    /**
     * 单文件上传
     *
     * @param id            文件ID
     * @param multipartFile 文件
     * @return 文件信息
     */
    FileTable upload(String id, MultipartFile multipartFile) throws IOException;

    /**
     * 多文件上传
     *
     * @param id             文件ID
     * @param multipartFiles 文件
     * @return 文件信息
     */
    List<FileTable> upload(String id, MultipartFile[] multipartFiles) throws IOException;

    /**
     * 通过主键删除数据
     *
     * @param id 文件ID
     * @return 是否成功
     */
    boolean deleteById(String id);

    /**
     * 条件查询
     *
     * @param fileTableCondition 实例对象
     * @return 文件信息
     */
    List<FileTable> queryByCondition(FileTableCondition fileTableCondition);


    /**
     * 文件下载
     *
     * @param id 文件ID
     * @return 文件流
     */
    ResponseEntity<FileSystemResource> downloadById(String id);

}

com/example/user/service/impl/FileTableServiceImpl.java

package com.example.user.service.impl;

import com.example.user.dao.FileTableDao;
import com.example.user.entity.FileTable;
import com.example.user.entity.FileTableCondition;
import com.example.user.service.FileTableService;
import com.example.user.utils.FileUtil;
import org.springframework.core.io.FileSystemResource;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Service;
import org.springframework.web.multipart.MultipartFile;

import javax.annotation.Resource;
import java.io.IOException;
import java.util.*;
import java.util.stream.Collectors;

/**
 * (FileTable)表服务实现类
 */
@Service("filesService")
public class FileTableServiceImpl implements FileTableService {

    @Resource
    private FileTableDao fileTableDao;

    /**
     * 单文件上传
     *
     * @param id            文件ID
     * @param multipartFile 文件
     * @return 文件信息
     */
    @Override
    public FileTable upload(String id, MultipartFile multipartFile) throws IOException {
        if (null == id || id.isEmpty()) {
            FileTable fileTable = FileUtil.saveFile("", multipartFile);
            this.fileTableDao.insert(fileTable);
            return this.fileTableDao.queryById(fileTable.getId());
        } else {
            FileTable fileTable = FileUtil.saveFile(id, multipartFile);
            this.fileTableDao.update(fileTable);
            return this.fileTableDao.queryById(fileTable.getId());
        }
    }

    /**
     * 多文件上传
     *
     * @param id             文件ID
     * @param multipartFiles 文件
     * @return 文件信息
     */
    @Override
    public List<FileTable> upload(String id, MultipartFile[] multipartFiles) throws IOException {
        List<FileTable> fileList = new ArrayList<>();
        for (MultipartFile multipartFile : multipartFiles) {
            fileList.add(FileUtil.saveFile("", multipartFile));
        }
        this.fileTableDao.insertList(fileList);
        List<String> ids = fileList.stream().map(FileTable::getId).collect(Collectors.toList());
        return this.fileTableDao.queryByIds(ids);
    }

    /**
     * 通过文件ID删除数据
     *
     * @param id 文件ID
     * @return 是否成功
     */
    @Override
    public boolean deleteById(String id) {
        return this.fileTableDao.deleteById(id) > 0;
    }

    /**
     * 条件查询
     *
     * @param fileTableCondition 实例对象
     * @return 文件信息
     */
    @Override
    public List<FileTable> queryByCondition(FileTableCondition fileTableCondition) {
        return this.fileTableDao.queryByCondition(fileTableCondition);
    }

    /**
     * 文件下载
     *
     * @param id 文件ID
     * @return 文件流
     */
    @Override
    public ResponseEntity<FileSystemResource> downloadById(String id) {
        FileTable fileTable = this.fileTableDao.queryById(id);
        return FileUtil.downloadFile(fileTable);
    }
}

com/example/user/dao/FileTableDao.java

package com.example.user.dao;

import com.example.user.entity.FileTable;
import com.example.user.entity.FileTableCondition;

import java.util.List;

/**
 * (FileTable)表数据库访问层
 */
public interface FileTableDao {

    /**
     * 新增数据
     *
     * @param files 实例对象
     * @return 影响行数
     */
    int insert(FileTable files);

    /**
     * 新增数据
     *
     * @param filesList 实例对象
     * @return 影响行数
     */
    int insertList(List<FileTable> filesList);

    /**
     * 通过主键删除数据
     *
     * @param id 文件ID
     * @return 影响行数
     */
    int deleteById(String id);

    /**
     * 修改数据
     *
     * @param fileTable 实例对象
     * @return 影响行数
     */
    int update(FileTable fileTable);

    /**
     * 按ID查询数据
     *
     * @param id 文件ID
     * @return 对象列表
     */
    FileTable queryById(String id);

    /**
     * 按ID查询数据
     *
     * @param ids 文件ID
     * @return 对象列表
     */
    List<FileTable> queryByIds(List<String> ids);

    /**
     * 按条件查询数据
     *
     * @param fileTableCondition 查询条件
     * @return 对象列表
     */
    List<FileTable> queryByCondition(FileTableCondition fileTableCondition);

}