SpringBoot加Poi仿照EasyPoi实现Excel导出

POI提供API给Java程序对Microsoft Office格式档案读和写的功能，详细功能可以直接查阅API,因为使用EasyPoi过程中总是缺少依赖，没有搞明白到底是什么坑，索性自己写一个简单工具类，来实现无论传入任何对象集合，都能够实现导出Excel的功能，没有看EasyPoi的源码， 只是在功能上模仿一下。

首先导入基本依赖，除了SpringBoot基本依赖依赖，导入Poi的依赖

<!-- https://mvnrepository.com/artifact/org.apache.poi/poi -->
        <dependency>
            <groupId>org.apache.poi</groupId>
            <artifactId>poi</artifactId>
            <version>3.17</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.apache.poi/poi-ooxml -->
        <dependency>
            <groupId>org.apache.poi</groupId>
            <artifactId>poi-ooxml</artifactId>
            <version>3.17</version>
        </dependency>

编写自定义注解

@Retention(RetentionPolicy.RUNTIME)
public @interface Excel {
    
    //Excel列名称
    String name() default "";
  
    //Excel列数
    int orderNum() default ;

}

编写javaBean,所有需要导出的属性都使用Excel注解

public class Person{

   private String id;

   @Excel(name = "用户姓名")
    private String userName;

    @Excel(name = "电话",orderNum = )
    private String phone;

   @Excel(name = "邮箱",orderNum = )
    private String email;

   @Excel(name = "地址",orderNum = )
    private  String address;

   public  void setId(String id){

    this.id=id;
    } 

    public String getId(){
       return id;
    }

   public  void setUserName(String userName){

    this.userName=userName;
    } 

    public String getUserName(){
       return userName;
    }

    public  void setphone(String phone){

      this.phone=phone;
    } 

    public String getphone(){
       return phone;
    }

   public  void setEmail(String email){

    this.email=email;
    } 

    public String getEmail(){
       return email;
    }

    public  void setAddress(String address){

    this.address=address;
    } 

    public String getAddress(){
       return address;
    }

}

编写工具类

public class PoiUtils {

    /**
     *
     * 功能描述:
     * 需要导出的属性要加Excel注解，实现Excel导出功能
     * @param: [list, fileName, sheetName, response, clazz]
     * @return: void
     * @auther: wang
     * @date: 2019/1/18 15:31
     */
    public Static <T> void export(Collection<T> collection, String fileName, String sheetName, HttpServletResponse response, Class<?> clazz) throws IOException, IntrospectionException, InvocationTargetException, IllegalAccessException {

        HSSFWorkbook workbook = new HSSFWorkbook();
        //创建一个Excel表单,参数为sheet的名字
        HSSFSheet sheet = workbook.createSheet(sheetName);
        //创建表头
        setTitle(workbook, sheet, clazz);
        //新增数据行，并且设置单元格数据
        int rowNum = ;
        for (T t : collection) {
            HSSFRow row = sheet.createRow(rowNum);
            Field[] fields = clazz.getDeclaredFields();
            for (Field field : fields) {
                if (field.isAnnotationPresent(Excel.class)) {
                    PropertyDescriptor pd = new PropertyDescriptor(field.getName(),
                            clazz);
                    Method getMethod = pd.getReadMethod();//获得get方法
                    Excel excel = field.getAnnotation(Excel.class);
                    row.createCell(excel.orderNum()).setCellValue(String.valueOf(getMethod.invoke(t)));

                }

            }
            rowNum++;
        }
        //清空response
        response.reset();
        // 告诉浏览器用什么软件可以打开此文件
        response.setHeader("content-Type", "application/vnd.ms-excel");
        // 下载文件的默认名称
        response.setHeader("Content-Disposition", "attachment;filename=" + URLEncoder.encode(fileName + ".xls", "utf-8"));
        OutputStream os;
        //可以将生成Excel默认下载到某个目录下
        //os = new BufferedOutputStream(new FileOutputStream("D:\\bmj\\target\\bmj128-0.0.1\\" + fileName));
        //也可以通过response得到输出流，写到输出流中，在页面中进行下载
        os = new BufferedOutputStream(response.getOutputStream());
        //将excel写入到输出流中
        workbook.write(os);
        os.flush();
        os.close();

    }

    /***
     * 设置表头
     * @param workbook
     * @param sheet
     */
    private static void setTitle(HSSFWorkbook workbook, HSSFSheet sheet, Class clazz) {
        HSSFRow row = sheet.createRow();
        Field[] fields = clazz.getDeclaredFields();
        //设置为居中加粗
        HSSFCellStyle style = workbook.createCellStyle();
        HSSFFont font = workbook.createFont();
        //设置字体
        font.setFontName("宋体");
        //设置粗体
        font.setBold(true);
        //设置字号
        font.setFontHeightInPoints((short) );
        //设置颜色
        font.setColor(IndexedColors.BLACK.index);
        style.setFont(font);
        HSSFCell cell;
        for (Field field : fields) {
            if (field.isAnnotationPresent(Excel.class)) {
                Excel excel = field.getAnnotation(Excel.class);
                cell = row.createCell(excel.orderNum());
                cell.setCellValue(excel.name());
                cell.setCellStyle(style);
                sheet.setColumnWidth(excel.orderNum(), *);
            }
        }

    }

}

页面调用，页面采用的是EasyUI框架

      <div style="padding:5px;background:#fafafa;width:100%;">
            <a href="javascript:void(0)" class="easyui-linkbutton" plain="true" iconCls="icon-undo"  onclick="downLoadExcel()">导出日志</a>
      </div>

可以按照页面给增加筛选条件，根据筛选条件下载

   function downLoadExcel(){

        var url=base+'/api/xx?xx='+$("#xx").val()+'&xx='+$("#xx").val()+'&xx='+$("#xx").val();
        window.location.href = url;

    }

编写Controller

@RestController
@RequestMapping(value = "/api/xx")
public class PersonController {

    private static final Logger LOG = LoggerFactory.getLogger(PersonController .class);
    @Resource(name = "personService")
    private PersonService personService;

    @RequestMapping("/export")
    public void export(PersonQuery personQuery, HttpServletResponse response) {

        List<Person> personList = personService.selectAll(personQuery);

        try {
            PoiUtils.export(auditLogList, "审计日志", "审计日志", response,AuditLog.class);
        } catch (IOException | IntrospectionException | InvocationTargetException | IllegalAccessException e) {
           LOG.error("审计日志错误{}",e);
        }

    }

}

页面如下

点击导出日志，显示如下

目前仅仅是针对单个sheet的操作，也没有像合并单元格这种复杂操作，需要继续完善。