导出数据到Excel，并把单元格内容转为字符串。
java
// 将单元格内容转化为字符串
private static String convertCellValueToString(Cell cell) {
if (null == cell) {
return null;
}
String returnValue = null;
switch (cell.getCellType()) {
case STRING: //字符串
returnValue = cell.getStringCellValue();
break;
case NUMERIC: //数字
double numericCellValue = cell.getNumericCellValue();
boolean isInteger = isInteger(numericCellValue);
if (isInteger) {
DecimalFormat df = new DecimalFormat("0");
returnValue = df.format(numericCellValue);
} else {
returnValue = Double.toString(numericCellValue);
}
break;
case BOOLEAN: //布尔
boolean booleanCellValue = cell.getBooleanCellValue();
returnValue = Boolean.toString(booleanCellValue);
break;
case BLANK: //空值
break;
case FORMULA: //公式
// returnValue = cell.getCellFormula();
try {
returnValue = String.valueOf(cell.getNumericCellValue());
} catch (IllegalStateException e) {
returnValue = String.valueOf(cell.getRichStringCellValue());
}
break;
case ERROR: //故障
break;
default:
break;
}
return returnValue;
}
// 判断是否为整数，是返回true，否则返回false.
public static boolean isInteger(Double num) {
double eqs = 1e-10; //精度范围
return num - Math.floor(num) < eqs;
}