1、我的项目构造

2、增加依赖

 <dependency>            <groupId>org.springframework.boot</groupId>            <artifactId>spring-boot-starter-data-jdbc</artifactId>        </dependency>        <dependency>            <groupId>org.springframework.boot</groupId>            <artifactId>spring-boot-starter-web</artifactId>        </dependency>        <dependency>            <groupId>org.mybatis.spring.boot</groupId>            <artifactId>mybatis-spring-boot-starter</artifactId>            <version>2.2.0</version>        </dependency>        <dependency>            <groupId>mysql</groupId>            <artifactId>mysql-connector-java</artifactId>            <scope>runtime</scope>        </dependency>        <dependency>            <groupId>org.projectlombok</groupId>            <artifactId>lombok</artifactId>            <optional>true</optional>        </dependency>        <dependency>            <groupId>com.alibaba</groupId>            <artifactId>easyexcel</artifactId>            <version>2.1.1</version>        </dependency>

3、application.properties配置

# 端口号server.port=1313# 数据库配置spring.datasource.url=jdbc:mysql:///数据库名?serverTimezone=GMT%2B8&characterEncoding=utf8# 数据库账号密码spring.datasource.username=账号spring.datasource.password=明码# mybatis配置mybatis.mapper-locations=classpath:/mapper/*.xmllogging.level.com.zj=debug

4、编写pojo层

@Datapublic class User implements Serializable {    private static final long serialVersionUID = 7957422435616014154L;    /**     *  @ExcelProperty(value="",index="",format="yyyy-MM-dd")     *  value   表头名称     *  index   输入的程序     *  format  工夫款式     *  @ColumnWidth为Excel的宽度     *  @DateTimeFormat("yyyy年MM月dd日HH时mm分ss秒")这里用string 去接日期能力格式化。我想接管年月日格局     */    @ExcelProperty(value = "学号",index = 0)    private Integer id;    @ExcelProperty(value = "姓名",index = 1)    private String name;}

5、编写mapper层

@Mapperpublic interface UserMapper {    /**     *  查问数据     * @return     */    List<User> dowloadExcel();}

6、编写UserMapper.xml

<?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.zj.mapper.UserMapper">    <select id="dowloadExcel" resultType="com.zj.pojo.User">        select * from user01;    </select></mapper>

7、编写UserService

public interface UserService {    /**     * 这里应用pom.xml的servlet-api依赖，负责像客户端（浏览器）发送响应     */    void downloadExcel(HttpServletResponse response) throws Exception;}

8、编写实现类

@Servicepublic class UserServiceImpl implements UserService {    @Autowired    private UserMapper userMapper;    @Override    public void downloadExcel(HttpServletResponse response) throws Exception {//      设置款式        String filename = URLEncoder.encode("myExcel", "utf-8");        response.setContentType("application/vnd.ms-excel");        response.setCharacterEncoding("utf-8");        response.setHeader("Content-Disposition","attachment;filename=" + filename + ".xlsx");        /**         * EasyExcel的写文件操作,data()办法用来查询数据库数据返回list         * sheet为excel的工作表表名         */        EasyExcel.write(response.getOutputStream(), User.class).sheet().doWrite(data());    }//  调用所查问的数据写入    private List<User> data() {        List<User> list = userMapper.dowloadExcel();        return list;    }}

9、controller层编写

@RestControllerpublic class UserController {    @Autowired    private UserService userService;    @GetMapping(value = "/downloadExcel")    public void downloadExcel(HttpServletResponse response) throws Exception{        userService.downloadExcel(response);    }}

10、测试

localhost:1313/downloadExcel