The maximum number of cell styles was exceeded. You can define up to 4000 styles

POI操作导出Excel中，导出的数据不是很大时，则不会有问题，而数据很多或者比较多时，

就会报以下的错误，是由于cell styles太多create造成，故一般可以把cellstyle设置放到循环外面

报错如下：

Caused by: 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:1144)

at org.apache.poi.hssf.usermodel.HSSFWorkbook.createCellStyle(HSSFWorkbook.java:88)

at com.trendmicro.util.toExcel.ExcelExporter.addWorkbook(ExcelExporter.java:612)

at com.trendmicro.util.toExcel.ExcelExporter.exportToExcel(ExcelExporter.java:112)

at com.trendmicro.util.toExcel.ReportExporter.exportAutomationReport(ReportExporter.java:190)

at com.trendmicro.view.reports.TestCaseAutomationBean.exportAutoReport(TestCaseAutomationBean.java:856)

at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)

at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)

at java.lang.reflect.Method.invoke(Method.java:597)

at org.apache.el.parser.AstValue.invoke(AstValue.java:191)

at org.apache.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:276)

at org.apache.jasper.el.JspMethodExpression.invoke(JspMethodExpression.java:68)

at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:88)

... 33 more