話不多說，直接上程式碼

資料庫表如下

程式碼結構如下

controller

package com.yuanyuan.smp.controller;

import java.util.List;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.poi.hssf.usermodel.HSSFCell;
import org.apache.poi.hssf.usermodel.HSSFCellStyle;
import org.apache.poi.hssf.usermodel.HSSFRow;
import org.apache.poi.hssf.usermodel.HSSFSheet;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import com.yuanyuan.smp.entity.User;
import com.yuanyuan.smp.service.IUserService;
import com.yuanyuan.smp.utils.FileUtil;

@RestController
public class UserController {
	
	@Autowired
	private IUserService userService;
	
	@RequestMapping("/")
	public String hello() {
		return "hello";
	}
	
	@RequestMapping("/exportExcel")
	public void exportExcel(HttpServletRequest request, HttpServletResponse response) {
		List<User> userList = userService.selectAll();
		// 建立工作簿
		HSSFWorkbook workbook = new HSSFWorkbook();
		// 建立表
		HSSFSheet sheet = workbook.createSheet("使用者資訊");
		// 建立行
		HSSFRow row = sheet.createRow(0);
		// 建立單元格樣式
		HSSFCellStyle cellStyle = workbook.createCellStyle();
		// 表頭
		String[] head = {"姓名", "年齡"};
		HSSFCell cell;
		// 設定表頭
		for(int iHead=0; iHead<head.length; iHead++) {
	    	cell = row.createCell(iHead);
	    	cell.setCellValue(head[iHead]);
	    	cell.setCellStyle(cellStyle);
	    }
		 // 設定表格內容
	    for(int iBody=0; iBody<userList.size(); iBody++) {
	    	row = sheet.createRow(iBody+1);
	    	User u = userList.get(iBody);
	    	String[] userArray = new String[2];
	    	userArray[0]=u.getName();
	    	userArray[1]=u.getAge() + "";
	    	for(int iArray=0; iArray<userArray.length; iArray++) {
	    		row.createCell(iArray).setCellValue(userArray[iArray]);
	        } 	
	    }
	    // 生成Excel檔案
	    FileUtil.createFile(response, workbook); 
	}
	
}
 

實體類

package com.yuanyuan.smp.entity;

import java.io.Serializable;

public class User implements Serializable{
    /**
	 * 
	 */
	private static final long serialVersionUID = 2895782870082326368L;

	private Integer userId;

    private String name;
    
    private Integer age;

    public Integer getUserId() {
        return userId;
    }

    public void setUserId(Integer userId) {
        this.userId = userId;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name == null ? null : name.trim();
    }

	public Integer getAge() {
		return age;
	}

	public void setAge(Integer age) {
		this.age = age;
	}
    
}
 

mapper

package com.yuanyuan.smp.mapper;

import java.util.List;

import com.yuanyuan.smp.entity.User;

public interface UserMapper {

    List<User> selectAll();

}

mapper.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.yuanyuan.smp.mapper.UserMapper" >
  <resultMap id="BaseResultMap" type="com.yuanyuan.smp.entity.User" >
    <id column="user_id" property="userId" jdbcType="INTEGER" />
    <result column="name" property="name" jdbcType="VARCHAR" />
    <result column="age" property="age" jdbcType="INTEGER" />
  </resultMap>
  <sql id="Base_Column_List" >
    user_id, name, age
  </sql>
  <select id="selectAll" resultMap="BaseResultMap" >
    select 
    <include refid="Base_Column_List" />
    from user
  </select>
</mapper>
 

Service

package com.yuanyuan.smp.service;

import java.util.List;

import com.yuanyuan.smp.entity.User;

public interface IUserService {
	
	List<User> selectAll();

}

package com.yuanyuan.smp.service;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import com.yuanyuan.smp.entity.User;
import com.yuanyuan.smp.mapper.UserMapper;

@Service
public class UserService implements IUserService {
	
	@Autowired
	private UserMapper userMapper;

	@Override
	public List<User> selectAll() {
		return userMapper.selectAll();
	}

}

utils

package com.yuanyuan.smp.utils;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;

import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletResponse;

import org.apache.poi.hssf.usermodel.HSSFWorkbook;

public class FileUtil {
	public static void createFile(HttpServletResponse response, HSSFWorkbook workbook) {
		// 設定檔名
	    String fileName ="使用者資訊";
	    try {
	    	// 捕獲記憶體緩衝區的資料，轉換成位元組陣列
	    	ByteArrayOutputStream out = new ByteArrayOutputStream();
	    	workbook.write(out);
	    	// 獲取記憶體緩衝中的資料
	    	byte[] content = out.toByteArray();
	    	// 將位元組陣列轉化為輸入流
	    	InputStream in = new ByteArrayInputStream(content);
	    	//通過呼叫reset（）方法可以重新定位。         	
	    	response.reset();
	        // 如果檔名是英文名不需要加編碼格式，如果是中文名需要新增"iso-8859-1"防止亂碼
	        response.setHeader("Content-Disposition", "attachment; filename=" + new String((fileName + ".xls").getBytes(), "iso-8859-1"));
	        response.addHeader("Content-Length", "" + content.length);
	        response.setContentType("application/vnd.ms-excel;charset=UTF-8");       	
	        ServletOutputStream outputStream = response.getOutputStream();
	        BufferedInputStream bis = new BufferedInputStream(in);
	        BufferedOutputStream bos = new BufferedOutputStream(outputStream);    
	        byte[] buff = new byte[8192];
	        int bytesRead;
	        while (-1 != (bytesRead = bis.read(buff, 0, buff.length))) {
	            bos.write(buff, 0, bytesRead);
	        }
	        bis.close();
	        bos.close();
	        outputStream.flush();
	        outputStream.close();
	    } catch (IOException e) {
	    	e.printStackTrace();
	    }
	}

}

啟動類

package com.yuanyuan.smp;

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

@SpringBootApplication
@MapperScan(basePackages= {"com.yuanyuan.smp.mapper"})
public class SmpApplication {
	
	public static void main(String[] args) {
		SpringApplication.run(SmpApplication.class, args);
	}

}

application.yml

server:
    port: 8088
    context-path: /
    tomcat:
        uri-encoding: UTF-8
spring:
    datasource:
        type: com.alibaba.druid.pool.DruidDataSource
        driverClassName: com.mysql.jdbc.Driver
        url: jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=UTF-8&allowMultiQueries=true
        username: root
        password: root
mybatis:
    mapper-locations: com.yuanyuan.smp.mapper/*.xml

pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.yuanyuan.smp</groupId>
  <artifactId>springboot-mybaits-poi</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  
  <parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>1.5.2.RELEASE</version>
    <relativePath/>
  </parent>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
    <java.version>1.8</java.version>
  </properties>
  
  <dependencies>
        <!-- mybatis -->
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>1.3.0</version>
        </dependency>
        <!-- spring boot jdbc -->
         <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jdbc</artifactId>
        </dependency>
        <!-- spring boot web -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <!-- mysql -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.0.29</version>
        </dependency>
        <dependency>
          <groupId>com.alibaba</groupId>
          <artifactId>fastjson</artifactId>
          <version>1.2.32</version>
        </dependency>
        <dependency>
            <groupId>org.apache.poi</groupId>
            <artifactId>poi</artifactId>
            <version>3.15</version>
        </dependency>
        <dependency>
            <groupId>org.apache.poi</groupId>
               <artifactId>poi-ooxml</artifactId>
               <version>3.15</version>
        </dependency>
    </dependencies>
    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>