java 读excel包括不同版本读取，读合并单元格和读公式

public String readPersonExcel(FileItem item,String reportType,int startRow) {

UPLOADREPORT = null; // 需自定义

String flag = "";
ArrayList<ReportBean> list = new ArrayList<ReportBean>(); // <RoadBean>需自定义
try {
InputStream excelResource = item.getInputStream();

Workbook rwb = WorkbookFactory.create(excelResource);
// 判断文件是什么格式 2003/2007 根据版本不同 处置对象也不同  
Sheet rs = rwb.getSheetAt(0);
// FormulaEvaluator evaluator = rwb.getCreationHelper().createFormulaEvaluator(); 
int rows = rs.getPhysicalNumberOfRows();

// 得到一个sheet中有多少个合并单元格
       int sheetmergerCount = rs.getNumMergedRegions();
for(int i = 0 ; i < sheetmergerCount ; i++){
Row row = rs.getRow(i);
CellRangeAddress ca = rs.getMergedRegion(i);     
int firstColumn = ca.getFirstColumn();     
int lastColumn = ca.getLastColumn();     
int firstRow = ca.getFirstRow();     
int lastRow = ca.getLastRow();  
int cha=lastRow-firstRow;
Row fRow = rs.getRow(firstRow); 
Cell fCell = fRow.getCell(firstColumn);
for(int n=firstRow;n<=lastRow;n++)
{
for(int m=firstColumn;m<=lastColumn;m++)
{
switch (fCell.getCellType()) {                                   
case Cell.CELL_TYPE_FORMULA:   
//str =cell.getCellFormula();   
try {
rs.getRow(n).getCell(m).setCellValue(fCell.getNumericCellValue());//可以算出有公式的
} catch (IllegalStateException e) {
rs.getRow(n).getCell(m).setCellValue(fCell.getRichStringCellValue());
}  
break; 
case Cell.CELL_TYPE_NUMERIC:   
if(HSSFDateUtil.isCellDateFormatted(fCell)){   
rs.getRow(n).getCell(m).setCellValue(fCell.getDateCellValue());
}else{   
rs.getRow(n).getCell(m).setCellValue(fCell.getNumericCellValue());
}  
break;                  
case Cell.CELL_TYPE_STRING:   
rs.getRow(n).getCell(m).setCellValue(fCell.getStringCellValue());
break;                
case Cell.CELL_TYPE_BOOLEAN:   
rs.getRow(n).getCell(m).setCellValue(fCell.getBooleanCellValue());
break;                 
default:   
}
}
}
}

ReportBean bean; // 需自定义
int endRow=rows;

if("57".equals(reportType))
{
if(rows < 20){
bean = new ReportBean();
bean.setExcelTemplate("1");
list.add(bean);
UPLOADREPORT = list; // 需自定义
return flag;
}

for (int i = 4; i < rows; i++) {
Row row = rs.getRow(i);
int cols = row.getPhysicalNumberOfCells();
//判断所读取的excel文件的列数是否与模板一致
if(cols != 16){
bean = new ReportBean();
bean.setExcelTemplate("1");
list.add(bean);
UPLOADREPORT = list; // 需自定义
return flag;
}

bean = new ReportBean(); // 需自定义
for (int j = 0; j < cols; j++) {
Cell cell = row.getCell(j);
DateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
String str = "";

switch (cell.getCellType()) {                                   
case Cell.CELL_TYPE_FORMULA:   
//str =cell.getCellFormula();   
try {
str = String.valueOf(cell.getNumericCellValue());
} catch (IllegalStateException e) {
str = String.valueOf(cell.getRichStringCellValue());
}  
break; 
case Cell.CELL_TYPE_NUMERIC:   
if(HSSFDateUtil.isCellDateFormatted(cell)){   
str =sdf.format(cell.getDateCellValue())+"";   
}else{   
str =cell.getNumericCellValue()+"";    
}  
break;                  
case Cell.CELL_TYPE_STRING:   
str = cell.getStringCellValue()+"";   
break;                
case Cell.CELL_TYPE_BOOLEAN:   
str = cell.getBooleanCellValue()+"";                            
break;                 
default:   
}

switch (j) {
case 0:
bean.setA1(str); 
break;
case 1:
bean.setA2(str);
break;

default:
break;
}
}

list.add(bean);
}
}

} catch (Exception e) {
e.printStackTrace();
}

UPLOADREPORT = list; // 需自定义

return flag;
}