2.4 注解变种-更自由的导出 === 这天老师又把路飞喊道的办公室,要求路飞导出班级学生的整体信息 ```java @Excel(name = "学生姓名", height = 20, width = 30, isImportField = "true_st") private String name; @Excel(name = "学生性别", replace = { "男_1", "女_2" }, suffix = "生", isImportField = "true_st") private int sex; @Excel(name = "出生日期", databaseFormat = "yyyyMMddHHmmss", format = "yyyy-MM-dd", isImportField = "true_st", width = 20) private Date birthday; @Excel(name = "进校日期", databaseFormat = "yyyyMMddHHmmss", format = "yyyy-MM-dd") private Date registrationDate; ``` 路飞飞快的用到上面的学到的知识搞定了,这这时有一个老师把路飞叫去,说想要导出一个不要出生日期的Excel,感觉用户需求很无奈,路飞又造两个一个bean,把这个注解去掉了,来导出 ```java @Excel(name = "学生姓名", height = 20, width = 30, isImportField = "true_st") private String name; @Excel(name = "学生性别", replace = { "男_1", "女_2" }, suffix = "生", isImportField = "true_st") private int sex; @Excel(name = "进校日期", databaseFormat = "yyyyMMddHHmmss", format = "yyyy-MM-dd") private Date registrationDate; ``` 虽然解决了老师的需求,但这个并不是一个完美的解决方案,下面介绍一个更自由的解决方案 注解的导出,规定我们必须把model写好,并且注解写好,每次导出的Excel都是固定的,无法动态控制导出的列,虽然可以通过id来处理一个案例,但是自由度远远不够,这里介绍个变种支持,基本支持注解所有的功能 基于List 的导出,ExcelExportEntity是注解经过处理翻译成的实体类,两者几乎是一对的,所以如果我们要动态自定义导出列,我们只要动态拼装ExcelExportEntity就可以了 下面我们看下这个类 ```java /** * 如果是MAP导出,这个是map的key */ private Object key; private double width = 10; private double height = 10; /** * 图片的类型,1是文件,2是数据库 */ private int exportImageType = 0; /** * 排序顺序 */ private int orderNum = 0; /** * 是否支持换行 */ private boolean isWrap; /** * 是否需要合并 */ private boolean needMerge; /** * 单元格纵向合并 */ private boolean mergeVertical; /** * 合并依赖 */ private int[] mergeRely; /** * 后缀 */ private String suffix; /** * 统计 */ private boolean isStatistics; private String numFormat; private List list; ``` 基本上是和注解对应的, **List list 这个是对应的一对多的导出,相当于集合,其他基本上都是和注解保持一致** 下面给出正常的demo ```java public void test() { try { List entity = new ArrayList(); //构造对象等同于@Excel ExcelExportEntity excelentity = new ExcelExportEntity("姓名", "name"); excelentity.setNeedMerge(true); entity.add(excelentity); entity.add(new ExcelExportEntity("性别", "sex")); excelentity = new ExcelExportEntity(null, "students"); List temp = new ArrayList(); temp.add(new ExcelExportEntity("姓名", "name")); temp.add(new ExcelExportEntity("性别", "sex")); //构造List等同于@ExcelCollection excelentity.setList(temp); entity.add(excelentity); List> list = new ArrayList>(); //把我们构造好的bean对象放到params就可以了 Workbook workbook = ExcelExportUtil.exportExcel(new ExportParams("测试", "测试"), entity, list); FileOutputStream fos = new FileOutputStream("D:/excel/ExcelExportForMap.tt.xls"); workbook.write(fos); fos.close(); } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } } ``` 路飞想到了这个方案,并且用上面做了测试可以完美解决所以他把之前的代码改为了(**代码有删减,基本上都是和注解对应的**) ```java List beanList = new ArrayList(); beanList .add(new ExcelExportEntity(new ExcelExportEntity("学生姓名", "name")); beanList .add(new ExcelExportEntity("学生性别", "sex")); beanList .add(new ExcelExportEntity("进校日期", "registrationDate")); if(needBirthday()){ beanList .add(new ExcelExportEntity("出生日期", "birthday")); } Workbook workbook = ExcelExportUtil.exportExcel(new ExportParams("测试", "测试"), beanList , list); ``` 用同一套代买完美了支持了老师的需求,心满意足的回宿舍了^^