spring boot 使用POI读取Excel文件
Excel文件目录
Excel模板文件存了resourse目录下，如下图：
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<dependency>
<groupId>org.apache.poi</groupId>
<artifactId>poi</artifactId>
<version>3.16</version>
</dependency>
<dependency>
<groupId>org.apache.poi</groupId>
<artifactId>poi-ooxml</artifactId>
<version>3.16</version>
</dependency>
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重要说明
如果是xls格式，使用HSSFWorkbook，HSSFSheet，HSSFRow来进行相关操作
如果是xlsx格式，使用XSSFWorkbook，XSSFSheet，XSSFRow来进行相关操作
读取Excel文件
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// 定义一个数据格式化对象
XSSFWorkbook wb = null;
try {
//excel模板路径
File cfgFile = ResourceUtils.getFile(ResourceUtils.CLASSPATH_URL_PREFIX + "static/ExcelTemplate/ContradictionMatrix.xlsx");
InputStream in = new FileInputStream(cfgFile);
//读取excel模板
wb = new XSSFWorkbook(in);
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
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获取sheet表格及读写单元格内容
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//获取sheet表格，及读取单元格内容
XSSFSheet sheet = null;
try{
sheet = wb.getSheetAt(0);
//先将获取的单元格设置为String类型，下面使用getStringCellValue获取单元格内容
//如果不设置为String类型，如果单元格是数字，则报如下异常
//java.lang.IllegalStateException: Cannot get a STRING value from a NUMERIC cell
sheet.getRow(2).getCell(2).setCellType(CellType.STRING);
//读取单元格内容
String cellValue = sheet.getRow(2).getCell(2).getStringCellValue();
//添加一行
XSSFRow row = sheet.createRow(1); //第2行开始写数据
row.setHeight((short)400); //设置行高
//向单元格写数据
row.createCell(1).setCellValue("名称");
}
catch (Exception e){
e.printStackTrace();
}
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合并单元格
使用下面的语句合并单元格：
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sheet.addMergedRegion(new CellRangeAddress(0,2,15,18));
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看一下CellRangeAddress的构造函数：
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/**
* Creates new cell range. Indexes are zero-based.
*
* @param firstRow Index of first row
* @param lastRow Index of last row (inclusive), must be equal to or larger than {@code firstRow}
* @param firstCol Index of first column
* @param lastCol Index of last column (inclusive), must be equal to or larger than {@code firstCol}
*/
public CellRangeAddress(int firstRow, int lastRow, int firstCol, int lastCol) {
super(firstRow, lastRow, firstCol, lastCol);
if (lastRow < firstRow || lastCol < firstCol)
throw new IllegalArgumentException("lastRow < firstRow || lastCol < firstCol");
}
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SpringBoot解析Excel
现在很多web应用中，导入excel导出excel很常见，这篇文章就讲讲导入excel文件。
以批量导入课程为例
首先加入需要的jar包
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<!--解析excel-->
<dependency>
<groupId>org.apache.poi</groupId>
<artifactId>poi</artifactId>
<version>RELEASE</version>
</dependency>
<dependency>
<groupId>org.apache.poi</groupId>
<artifactId>poi-ooxml</artifactId>
<version>RELEASE</version>
</dependency>
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数据库中创建一个表course
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DROP TABLE IF EXISTS `course`;
CREATE TABLE `course` (
`course_id` int(10) NOT NULL AUTO_INCREMENT COMMENT '课程id',
`course_code` varchar(100) CHARACTER SET utf8 COLLATE utf8_bin NOT NULL COMMENT '课程代码',
`course_name` varchar(255) CHARACTER SET utf8 COLLATE utf8_bin NOT NULL COMMENT '课程名称',
`teacher_id` varchar(100) CHARACTER SET utf8 COLLATE utf8_bin NOT NULL COMMENT '教师id',
`course_time` date NOT NULL DEFAULT '1996-01-01' COMMENT '开课时间',
`class_room` varchar(255) CHARACTER SET utf8 COLLATE utf8_bin NOT NULL COMMENT '开课地点',
`course_week` int(5) UNSIGNED NOT NULL DEFAULT 0 COMMENT '课程学时',
`course_type` varchar(100) CHARACTER SET utf8 COLLATE utf8_bin NOT NULL DEFAULT '必修课' COMMENT '课程类型',
`college_id` int(11) UNSIGNED NOT NULL COMMENT '所属院系id',
`score` int(5) UNSIGNED NOT NULL DEFAULT 0 COMMENT '学分',
`is_on` tinyint(2) UNSIGNED NOT NULL DEFAULT 0 COMMENT '是否开启了选课，默认0未开启',
PRIMARY KEY (`course_id`) USING BTREE
) ENGINE = InnoDB AUTO_INCREMENT = 7 CHARACTER SET = utf8mb4 COLLATE = utf8mb4_general_ci COMMENT = '课程表' ROW_FORMAT = Dynamic;
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新建一个ExcelUtil.java
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/**
* excel工具类
*/
public class ExcelUtils {
private static Logger logger = LoggerFactory.getLogger(ExcelUtils.class);
/**
* 课程excel
* @param in
* @param fileName
* @return
* @throws Exception
*/
public static List getCourseListByExcel(InputStream in, String fileName) throws Exception {
List list = new ArrayList<>();
// 创建excel工作簿
Workbook work = getWorkbook(in, fileName);
if (null == work) {
throw new Exception("创建Excel工作薄为空！");
}
Sheet sheet = null;
Row row = null;
Cell cell = null;
for (int i = 0; i < work.getNumberOfSheets(); i++) {
sheet = work.getSheetAt(i);
if(sheet == null) {
continue;
}
// 滤过第一行标题
for (int j = sheet.getFirstRowNum(); j <= sheet.getLastRowNum(); j++) {
row = sheet.getRow(j);
if (row == null || row.getFirstCellNum() == j) {
continue;
}
List<Object> li = new ArrayList<>();
for (int y = row.getFirstCellNum(); y < row.getLastCellNum(); y++) {
cell = row.getCell(y);
// 日期类型转换
if(y == 3) {
//cell.setCellType(CellType.STRING);
double s1 = cell.getNumericCellValue();
Date date = HSSFDateUtil.getJavaDate(s1);
li.add(date);
continue;
}
li.add(cell);
}
list.add(li);
}
}
work.close();
return list;
}
/**
* 判断文件格式
* @param in
* @param fileName
* @return
*/
private static Workbook getWorkbook(InputStream in, String fileName) throws Exception {
Workbook book = null;
String filetype = fileName.substring(fileName.lastIndexOf("."));
if(".xls".equals(filetype)) {
book = new HSSFWorkbook(in);
} else if (".xlsx".equals(filetype)) {
book = new XSSFWorkbook(in);
} else {
throw new Exception("请上传excel文件！");
}
return book;
}
}
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这里主要注意一下上面的日期转换，在excel中的日期，通过Java读出来之后，变成了26 四月 2019这样的形式，而数据库中我们的字段类型为date，所以总是插入失败。
上面我的写法直接是知道那个字段是Date类型，所以直接使用y==3，这样写可复用性很差。
接下来直接看和数据库交互的逻辑代码
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/**
* 通过excel文件，批量增加课程
* @param request
* @return
* @throws Exception
*/
@PostMapping("/upload/course")
public String uploadCourseExcel(HttpServletRequest request) {
MultipartHttpServletRequest multipartHttpServletRequest = (MultipartHttpServletRequest) request;
MultipartFile file = multipartHttpServletRequest.getFile("courseFile");
if(file.isEmpty()) {
return "redirect:/admin/course/list";
}
try {
InputStream inputStream = file.getInputStream();
List<List<Object>> list = ExcelUtils.getCourseListByExcel(inputStream, file.getOriginalFilename());
inputStream.close();
for (int i = 0; i < list.size(); i++) {
List<Object> courseList = list.get(i);
Course course = new Course();
course.setCourseCode(courseList.get(0).toString());
course.setCourseName(courseList.get(1).toString());
// 通过教师姓名查教师id
String teacherId = teacherService.getTeacByName(courseList.get(2).toString());
// 教师信息错误，直接跳过这条记录
if(teacherId == null) {
continue;
}
course.setTeacherId(teacherId);
// 格式化时间
Date date = new SimpleDateFormat("EEE MMM dd HH:mm:ss zzz yyyy", Locale.US).parse(courseList.get(3).toString());
course.setCourseTime(new SimpleDateFormat("yyyy-MM-dd").parse(new SimpleDateFormat("yyyy-MM-dd").format(date)));
course.setClassRoom(courseList.get(4).toString());
course.setCourseWeek(Integer.parseInt(new DecimalFormat("0").format(Double.parseDouble(courseList.get(5).toString()))));
course.setCourseType(courseList.get(6).toString());
// 通过院系名称查询院系id
Integer collegeId = collegeService.getCollegeByName(courseList.get(7).toString());
// 院系有误，直接跳过这条记录
if(collegeId == null || collegeId == 0) {
continue;
}
course.setCollegeId(collegeId);
course.setScore(Integer.parseInt(new DecimalFormat("0").format(Double.parseDouble(courseList.get(8).toString()))));
// 默认不开启选课
course.setIsOn(0);
logger.error("course = " + course);
// 判断课程是否重复(同一门课程可以有多个教师教师course_code, course_name, teacher_id联合)
Integer courseId = null;
courseId = courseService.getCourseByThree(course);
// 存在重复的
if(courseId != null) {
// 跳过不添加
continue;
}
// 执行插入操作
courseService.addCourse(course);
}
} catch (Exception e) {
return "redirect:/admin/course/list";
}
return "redirect:/admin/course/list";
}
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可以看到，我又对时间类型进行了处理，才能最终插入数据库
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// 格式化时间
Date date = new SimpleDateFormat("EEE MMM dd HH:mm:ss zzz yyyy", Locale.US).parse(courseList.get(3).toString());
course.setCourseTime(new SimpleDateFormat("yyyy-MM-dd").parse(new SimpleDateFormat("yyyy-MM-dd").format(date)));
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同时，在excel中的整数类型，取出来之后就会变成Double类型比如5变成5.0，所以我对此也进行了处理
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course.setCourseWeek(Integer.parseInt(new DecimalFormat("0").format(Double.parseDouble(courseList.get(5).toString()))));
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最后调用代码进行插入操作。
看看前端代码
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<button class="btn btn-default col-md-2" style="margin-top: 20px">
<a data-toggle="modal" href="#uploadExcel" rel="external nofollow" role="button" style="color: black; text-decoration: none">
批量添加<sapn class="glyphicon glyphicon-plus"/>
</a>
</button>
<!--批量添加模态框-->
<div class="modal fade" tabindex="-1" role="dialog" id="uploadExcel">
<div class="modal-dialog" role="document">
<div class="modal-content">
<form class="form-horizontal" role="form" th:action="@{/admin/upload/course}"
enctype="multipart/form-data" method="post">
<div class="modal-body">
请选择文件:<input type="file" name="courseFile">
</div>
<div class="modal-footer">
<button type="button" class="btn btn-default" data-dismiss="modal">关闭</button>
<button type="submit" class="btn btn-success">添加</button>
</div>
</form>
</div>
</div>
</div>
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这里我通过button唤醒一个模态框来添加
最后测试结果
以上为个人经验，希望能给大家一个参考，也希望大家多多支持服务器之家。
原文链接：https://www.cnblogs.com/codecat/p/10948120.html