jxl写excel出现得问题

[zhouyan024]

Workbook   wb   =   Workbook.getWorkbook(new   File(strFileName));               
ByteArrayOutputStream   targetFile   =   new   ByteArrayOutputStream();           
WritableWorkbook   wwb   =   Workbook.createWorkbook(targetFile,   wb);             
WritableSheet   wws   =   wwb.getSheet(0);     
for     (int   r=3;r <=26;r++) 
{ 
for     (int   c=4;c <=7;c++)       
{   
WritableCell   wc1   =   wws.getWritableCell(c,r); 
Label   sex   =   (Label)wc1; 
sex.setString( "a "); 
} 
} 

到Label sex = (Label)wc1; 报错，因为模板这个单元格是空的，把这个单元格填上数据就没错了，想知道，单元格为空的时候怎么写

[yeyuxiner]

先判断单元格是否为空，为空的话设个空字符串 "" 试试