請高手們指點。感激不盡，在線等

各位大俠幫個忙，我在用POI導Excel資料時，碰到如下問題
An error occurred at line: 11 in the jsp file: /inexcel.jsp
Generated servlet error:
C:\Program Files\Apache Software Foundation\Tomcat 5.0\work\Catalina\220.249.255.188\payment\org\apache\jsp\inexcel_jsp.java:93: inconvertible types
found   : double
required: java.lang.Double
                      cell_value = ((Double)cell.getNumericCellValue()).toString()   ;
                                                                    ^
1 error org.apache.jasper.compiler.DefaultErrorHandler.javacError(DefaultErrorHandler.java:84)
org.apache.jasper.compiler.ErrorDispatcher.javacError(ErrorDispatcher.java:332)
org.apache.jasper.compiler.Compiler.generateClass(Compiler.java:412)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:472)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:451)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:439)
org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:511)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:295)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:292)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:236)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
請高手們指點。感激不盡，在線等主要出錯的代碼如下
switch(cell.getCellType())   //判断类型 
                 {   
                   case   HSSFCell.CELL_TYPE_NUMERIC:    
                      cell_value = ((Double)cell.getNumericCellValue()).toString()   ;
                      break;   
                   case  HSSFCell.CELL_TYPE_STRING:   
                     cell_value = cell.getStringCellValue();   
                      break;   
                  //case   HSSFCell.CELL_TYPE_FORMULA:   
                  //cell_value   =   cell.getCellFormula();   
                  //break;   
                      default: 
                  cell_value= " <font   color=red></font> "; 
                 }   //end   switch