poi的excel导出
这个导出依赖于模板文件，可便捷设置表头样式。 也可以不使用模板，直接创建。
1.引入poi依赖
<dependency><groupId>org.apache.poi</groupId><artifactId>poi</artifactId><version>4.1.2</version>
</dependency>
2.准备模板文件
3.编写导出代码
测试代码直接导出到本地，如需要在浏览器中导出将输出流交给浏览器即可
public class GenerateExcel {public static void main(String[] args) throws IOException {GenerateExcelXlsx();}static void GenerateExcelXlsx() throws IOException {List<Student> students = new Student().stuAll();InputStream inputStream = GenerateExcel.class.getClassLoader().getResourceAsStream("static/测试填充excel.xlsx");XSSFWorkbook workbook = new XSSFWorkbook(inputStream);// 获取第一个sheetSheet sheet = workbook.getSheetAt(0);int index = 2;for (Student item : students) {Row row = sheet.createRow(index);row.createCell(0).setCellValue(item.getName());row.createCell(1).setCellValue(item.getSex().toString());row.createCell(2).setCellValue(item.getAge());index += 1;}FileOutputStream outputStream = new FileOutputStream("C:\\Users\\pyb\\Desktop\\a.xlsx");workbook.write(outputStream);outputStream.flush();outputStream.close();}static class Student{private String name;private Integer age;private Character sex;public Student() {}public Student(String name, Character sex, Integer age) {this.name = name;this.sex = sex;this.age = age;}List<Student> stuAll(){ArrayList<Student> list = new ArrayList<>();for (int i = 0; i < 5; i++) {Student student = new Student("张三" + i, '男' ,18 );list.add(student);}return list;}public String getName() {return name;}public Integer getAge() {return age;}public Character getSex() {return sex;}}}
4.运行后效果图
5.不依赖模板直接导出
这种方式表头内容需要自己手动写，
public class GenerateExcel {public static void main(String[] args) throws IOException {GenerateExcelXlsx2();}static void GenerateExcelXlsx2() throws IOException {List<Student> students = new Student().stuAll();XSSFWorkbook workbook = new XSSFWorkbook();// 创建一个sheet，这里面形参是内部名称，不可见Sheet sheet = workbook.createSheet();// 设置为第几个sheet，并设置用户可见名称workbook.setSheetName(0,"测试sheet");int index = 0;for (Student item : students) {Row row = sheet.createRow(index);row.createCell(0).setCellValue(item.getName());row.createCell(1).setCellValue(item.getSex().toString());row.createCell(2).setCellValue(item.getAge());index += 1;}FileOutputStream outputStream = new FileOutputStream("C:\\Users\\pyb\\Desktop\\b.xlsx");workbook.write(outputStream);outputStream.flush();outputStream.close();}static class Student{private String name;private Integer age;private Character sex;public Student() {}public Student(String name, Character sex, Integer age) {this.name = name;this.sex = sex;this.age = age;}List<Student> stuAll(){ArrayList<Student> list = new ArrayList<>();for (int i = 0; i < 5; i++) {Student student = new Student("张三" + i, '男' ,18 );list.add(student);}return list;}public String getName() {return name;}public Integer getAge() {return age;}public Character getSex() {return sex;}}}
应用模板表格中的格式
一般应用与固定位置填充完毕的计算，动态的没测试过
数据塞入完毕后加入以下代码
// 计算公式
FormulaEvaluator evaluator = workbook.getCreationHelper().createFormulaEvaluator();
evaluator.evaluateAll();总结
获取某行或者某列时候，尽量用创建方式，除非确定行和列都能被获取到（行列不做操作、修改格式的情况下内容是空，会报空指针）
