java.lang.IllegalStateException: The maximum numbe

错误：

java.lang.IllegalStateException: The maximum number of cell styles was exceeded. You can define up to 4000 styles in a .xls workbook

        at org.apache.poi.hssf.usermodel.HSSFWorkbook.createCellStyle(HSSFWorkbook.java:1162)

原因是：

Wrong :

for (int i = 0; i < 10000; i++) {

Row row = sheet.createRow(i);

Cell cell = row.createCell((short) 0);

CellStyle style = workbook.createCellStyle();

Font font = workbook.createFont();

font.setBoldweight(Font.BOLDWEIGHT_BOLD);

style.setFont(font);

cell.setCellStyle(style);

}

Correct:

CellStyle style = workbook.createCellStyle();

Font font = workbook.createFont();

font.setBoldweight(Font.BOLDWEIGHT_BOLD);

style.setFont(font);

for (int i = 0; i < 10000; i++) {

Row row = sheet.createRow(i);

Cell cell = row.createCell((short) 0);

cell.setCellStyle(style);

}

Note : LOC of creating fonts is inside the loop , because when you are writing the records to the row.  there is no need of keeping the font creation in loop , better move it outside the loop and try it . Sure popup message will not come in case of large datas populated in the worksheet .