1.Excel文件放在src/man/resources/templates下；

2.修改pom.xml文件中的maven打包方式

<build>
   <plugins>
      <plugin>
         <groupId>org.springframework.boot</groupId>
         <artifactId>spring-boot-maven-plugin</artifactId>
      </plugin>
      <plugin>
         <groupId>org.apache.maven.plugins</groupId>
         <version>2.6</version>
         <artifactId>maven-resources-plugin</artifactId>
         <configuration>
            <encoding>UTF-8</encoding>
            <nonFilteredFileExtensions>
               <nonFilteredFileExtension>xlsx</nonFilteredFileExtension>
            </nonFilteredFileExtensions>
         </configuration>
      </plugin>
   </plugins>
</build>

3.创建相应的Controller

import io.swagger.annotations.Api;
import io.swagger.annotations.ApiOperation;
import lombok.extern.slf4j.Slf4j;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import javax.annotation.Resource;
import java.net.URLEncoder;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.*;
import org.apache.commons.io.IOUtils;
import org.springframework.core.io.ResourceLoader;
import java.nio.charset.StandardCharsets;

@RestController
@Api(tags = "下载模板")
@RequestMapping("download")
@Slf4j
public class DownloadController {

    @Resource
    private ResourceLoader resourceLoader;

    @ApiOperation(value = "模板1", httpMethod = "GET")
    @GetMapping("template")
    public void downloadBlacklistTemplate(HttpServletRequest request, HttpServletResponse response){
        InputStream inputStream = null;
        ServletOutputStream servletOutputStream = null;
      try {
            String filename = "template.xlsx";
            String path = "templates/template.xlsx";
            org.springframework.core.io.Resource resource = resourceLoader.getResource("classpath:"+path);

            response.setContentType("application/vnd.ms-excel");
            response.addHeader("Cache-Control", "no-cache, no-store, must-revalidate");
            response.addHeader("charset", "utf-8");
            response.addHeader("Pragma", "no-cache");
            String encodeName = URLEncoder.encode(filename, StandardCharsets.UTF_8.toString());
            response.setHeader("Content-Disposition", "attachment; filename=\"" + encodeName + "\"; filename*=utf-8''" + encodeName);

            inputStream = resource.getInputStream();
            servletOutputStream = response.getOutputStream();
            IOUtils.copy(inputStream, servletOutputStream);
            response.flushBuffer();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                if (servletOutputStream != null) {
                    servletOutputStream.close();
                    servletOutputStream = null;
                }
                if (inputStream != null) {
                    inputStream.close();
                    inputStream = null;
                }
                // 召唤jvm的垃圾回收器
                System.gc();
            } catch (Exception e) {
                e.printStackTrace();
            }
      }
    }
}

4.运行项目