一、基本操作见：使用POI导出Excel
二、本次功能需求
给了一个模板，里面有6个sheet页，每页里面都需要填充相应的数据。如图：
三、需求分析
1、分了6个sheet页，每页的数据都不一样，首先代码里要获得它们的数据，然后6个sheet页只能一个个填进去，没法批量操作。
2、如果直接代码创建Excel并画表格样式和数据，那么工程量将会很大，而且会导致代码很乱。我采用的方法是把模板保存到项目里，再通过路径获取到该模板文件，把其内容全部复制到新创建的Excel中，再往里填充数据。
3、注意到第一张图中有总计这一行，我的建议是先在代码中计算出相应的数据，再填充，我也是这样做的。当然，我的第一想法是给它设置函数公式，但是后来我并没有这么做。
4、从第二张图中可以看得出要填充的数据的行是不固定的，除非规定了只填充前几条数据。而在11、12行中的数据是已经有了的，当填充的数据太多，就会覆盖掉那行数据。有两种方法解决，一是把它获取到，先填充数据覆盖掉，再在最后一条数据的下一行把它再填充回去。二是根据数据的总条数通过代码往中间插入空白行。两种方法都可行，我采用了第二种。
四、上代码
public void exportAll() {
OutputStream out = null;
try {
// 获取数据
List<BaseTalentFlowAnalysisGridVo> talentFlows = this.talentFlowQuestionnaireService.listAnalysis();
List<BaseBasicSituationAnalysisGridVo> basicSituations = this.basicSituationService.listAnalysis();
List<BaseTalentInputAnalysisGridVo> talentInputs = this.talentInputService.listAnalysis();
List<BaseTalentDemandAnalysisGridVo> talentDemands = this.talentDemandService.listAnalysis();
List<BaseHighLevelTalentsRosterAnalysisGridVo> talentRosters = this.rosterService.listAnalysis();
Map<String, Object> results = new HashMap<>();
results.put("talentFlows", talentFlows);
results.put("basicSituations", basicSituations);
results.put("talentInputs", talentInputs);
results.put("talentDemands", talentDemands);
results.put("talentRosters", talentRosters);
// 拿到模板文件
String path = ServletActionContext.getServletContext().getRealPath("/");
String filePath = path + "\\resources\\temp\\人才统计报表模板.xls";
FileInputStream tps = new FileInputStream(new File(filePath));
final HSSFWorkbook tpWorkbook = new HSSFWorkbook(tps);
out = response.getOutputStream();
response.reset();
response.setHeader("content-disposition",
"attachment;filename=" + new String(("人才统计报表").getBytes("gb2312"), "ISO8859-1") + ".xls");
response.setContentType("APPLICATION/msexcel");
// 新建一个Excel的工作空间
HSSFWorkbook workbook = new HSSFWorkbook();
// 把模板复制到新建的Excel
workbook = tpWorkbook;
// 填充数据
this.excelService.addData(workbook, results);
// 输出Excel内容，生成Excel文件
workbook.write(out);
} catch (final IOException e) {
LOGGER.error(e);
} catch (final IllegalArgumentException e) {
LOGGER.error(e);
} catch (final Exception e) {
LOGGER.error(e);
} finally {
try {
// 最后记得关闭输出流
response.flushBuffer();
if (out != null) {
out.flush();
out.close();
}
} catch (final IOException e) {
LOGGER.error(e);
}
}
}
/**
* 第二个sheet页：人才流动情况表
*
* @param workbook
* @param talentFlows
*/
private void addTalentFlows(HSSFWorkbook workbook, List<BaseTalentFlowAnalysisGridVo> talentFlows) {
// 获取第二个sheet页
Sheet talentFlowSheet = workbook.getSheetAt(1);
Row talentFlowRow = talentFlowSheet.getRow(0);
// 声明总计的那几个数据
Integer totalLastYearTotal = 0;
Integer totalHighLevelTalent = 0;
Integer totalUndergraduateAndGraduate = 0;
Integer totalCollegeStudents = 0;
Integer totalSocialTalent = 0;
Integer totalMilitaryTransferCadres = 0;
Integer totalReturnees = 0;
Integer totalRetirement = 0;
Integer totalResignation = 0;
Integer totalDismiss = 0;
Integer totalOther = 0;
Integer totalAverageIncrease = 0;
Integer totalAverageReduction = 0;
// 循环数据
for (BaseTalentFlowAnalysisGridVo baseTalentFlowAnalysisGridVo : talentFlows) {
// 循环行
for (int tr = 4; tr < 11; tr++) {
talentFlowRow = talentFlowSheet.getRow(tr);
// 当数据的项目字段和行的第一列内容相等，则把该条数据填入该行
if (talentFlowRow.getCell(0).getStringCellValue()
.equals(baseTalentFlowAnalysisGridVo.getFkProjectName())) {
talentFlowRow.getCell(1).setCellValue(baseTalentFlowAnalysisGridVo.getLastYearTotal());
// 给总计做计算
totalLastYearTotal += baseTalentFlowAnalysisGridVo.getLastYearTotal();
talentFlowRow.getCell(2).setCellValue(baseTalentFlowAnalysisGridVo.getHighLevelTalent());
totalHighLevelTalent += baseTalentFlowAnalysisGridVo.getHighLevelTalent();
talentFlowRow.getCell(3).setCellValue(baseTalentFlowAnalysisGridVo.getUndergraduateAndGraduate());
totalUndergraduateAndGraduate += baseTalentFlowAnalysisGridVo.getUndergraduateAndGraduate();
talentFlowRow.getCell(4).setCellValue(baseTalentFlowAnalysisGridVo.getCollegeStudents());
totalCollegeStudents += baseTalentFlowAnalysisGridVo.getCollegeStudents();
talentFlowRow.getCell(5).setCellValue(baseTalentFlowAnalysisGridVo.getSocialTalent());
totalSocialTalent += baseTalentFlowAnalysisGridVo.getSocialTalent();
talentFlowRow.getCell(6).setCellValue(baseTalentFlowAnalysisGridVo.getMilitaryTransferCadres());
totalMilitaryTransferCadres += baseTalentFlowAnalysisGridVo.getMilitaryTransferCadres();
talentFlowRow.getCell(7).setCellValue(baseTalentFlowAnalysisGridVo.getReturnees());
totalReturnees += baseTalentFlowAnalysisGridVo.getReturnees();
talentFlowRow.getCell(8).setCellValue(baseTalentFlowAnalysisGridVo.getRetirement());
totalRetirement += baseTalentFlowAnalysisGridVo.getRetirement();
talentFlowRow.getCell(9).setCellValue(baseTalentFlowAnalysisGridVo.getResignation());
totalResignation += baseTalentFlowAnalysisGridVo.getResignation();
talentFlowRow.getCell(10).setCellValue(baseTalentFlowAnalysisGridVo.getDismiss());
totalDismiss += baseTalentFlowAnalysisGridVo.getDismiss();
talentFlowRow.getCell(11).setCellValue(baseTalentFlowAnalysisGridVo.getOther());
totalOther += baseTalentFlowAnalysisGridVo.getOther();
talentFlowRow.getCell(12).setCellValue(baseTalentFlowAnalysisGridVo.getAverageIncrease());
totalAverageIncrease += baseTalentFlowAnalysisGridVo.getAverageIncrease();
talentFlowRow.getCell(13).setCellValue(baseTalentFlowAnalysisGridVo.getAverageReduction());
totalAverageReduction += baseTalentFlowAnalysisGridVo.getAverageReduction();
break;
}
}
}
// 给总计行填充数据
talentFlowRow = talentFlowSheet.getRow(11);
talentFlowRow.getCell(1).setCellValue(totalLastYearTotal);
talentFlowRow.getCell(2).setCellValue(totalHighLevelTalent);
talentFlowRow.getCell(3).setCellValue(totalUndergraduateAndGraduate);
talentFlowRow.getCell(4).setCellValue(totalCollegeStudents);
talentFlowRow.getCell(5).setCellValue(totalSocialTalent);
talentFlowRow.getCell(6).setCellValue(totalMilitaryTransferCadres);
talentFlowRow.getCell(7).setCellValue(totalReturnees);
talentFlowRow.getCell(8).setCellValue(totalRetirement);
talentFlowRow.getCell(9).setCellValue(totalResignation);
talentFlowRow.getCell(10).setCellValue(totalDismiss);
talentFlowRow.getCell(11).setCellValue(totalOther);
talentFlowRow.getCell(12).setCellValue(totalAverageIncrease);
talentFlowRow.getCell(13).setCellValue(totalAverageReduction);
}
/**
* 第四个sheet页：人才需求情况调查表
*
* @param workbook
* @param talentFlows
*/
private void addalentDemands(HSSFWorkbook workbook, List<BaseTalentDemandAnalysisGridVo> talentDemands)
throws IllegalArgumentException, IllegalAccessException {
Sheet talentDemandSheet = workbook.getSheetAt(3);
Row talentDemandRow = talentDemandSheet.getRow(4);
// 如果数据大于模板中的行数，插入行并复制第一行数据的格式
if (talentDemands.size() > 5) {
// 插入行，5是模板中已有的行数
talentDemandSheet.shiftRows(5, talentDemandSheet.getLastRowNum(), talentDemands.size() - 5, true, false);
Row sourceRow = talentDemandSheet.getRow(4);
for (int i = 0; i < talentDemands.size() - 5; i++) {
Row newRow = talentDemandSheet.createRow(4 + i + 1);
newRow.setHeight(sourceRow.getHeight());
for (int j = 0; j < sourceRow.getLastCellNum(); j++) {
Cell templateCell = sourceRow.getCell(j);
if (templateCell != null) {
Cell newCell = newRow.createCell(j);
copyCell(templateCell, newCell);
}
}
}
}
// 填充数据
for (int i = 0; i < talentDemands.size(); i++) {
talentDemandRow = talentDemandSheet.getRow(4 + i);
talentDemandRow.getCell(0).setCellValue(talentDemands.get(i).getPositionTitle());
talentDemandRow.getCell(2).setCellValue(talentDemands.get(i).getDemand());
talentDemandRow.getCell(3).setCellValue(talentDemands.get(i).getAge());
talentDemandRow.getCell(4).setCellValue(talentDemands.get(i).getFkAcademicDegreeName());
talentDemandRow.getCell(5).setCellValue(talentDemands.get(i).getTechnicalTitles());
talentDemandRow.getCell(6).setCellValue(talentDemands.get(i).getProfession());
talentDemandRow.getCell(7).setCellValue(talentDemands.get(i).getFkTalentCategoryName());
talentDemandRow.getCell(8).setCellValue(talentDemands.get(i).getFkServiceFormName());
talentDemandRow.getCell(9).setCellValue(talentDemands.get(i).getProvide());
talentDemandRow.getCell(10).setCellValue(talentDemands.get(i).getOtherCases());
talentDemandRow.getCell(11).setCellValue(talentDemands.get(i).getFkIntentionToChooseName());
}
}
五、缺点：一手烂代码，应该给对象设置对应的中文注释，和模板中的列头一样，然后再通过循环填充数据。这样一个个填上去太傻了。
六、通过实验测试，在getCell的时候，如果那是个合并的单元格，那么该单元格的数据存在了左上角，其他的格内容为空。