//获取ColumnHeader拦
JRDesignBand columnHeaderBand = (JRDesignBand)jasperDesign.getColumnHeader();
JRDesignBand detailBand = (JRDesignBand )jasperDesign.getDetailSection().getBands()[0];
JRElement[] es_header = columnHeaderBand.getElements();
JRDesignStaticText columnHeaderField = (JRDesignStaticText)columnHeaderBand.getElementByKey("aa");
JRDesignTextField detailField= (JRDesignTextField )detailBand.getElementByKey("ss");
columnHeaderBand.removeElement(columnHeaderField);
detailBand.removeElement(detailField);//得到对象之后 将其从xml的文件中移除
columnHeaderField 和detailField都为空，导致删除和添加列报错，getElementByKey获取的Key是列的字段名吗？现在获取字段名出现null，有哪位遇到过，求解决
