1. 最先存储的是Workbook Globals Substream
2. 接着是第一个Sheet Substream
3. Sheet Substream的存储顺序是根据Excel中Sheet的顺序来的

四. 记录Record

• BOFRecord : 记录了Workbook或一个sheet的开始
• EOFRecord : 记录了Workbook或一个sheet的结尾
• STRecord ： 记录了Excel中所有文件大院个的文本值
• .......

1. Identifier：Record的标识符sid，POI读取到sid就知道将流解析成对应的Record
2. size ：记录了当前Record内容占据的大小，单位为字节
3. content：当前Record的内容

@SuppressWarnings("unchecked")
private static final Class<? extends Record>[] recordClasses = new Class[] {  ArrayRecord.class,  AutoFilterInfoRecord.class,  BackupRecord.class,  BlankRecord.class,  BOFRecord.class,  BookBoolRecord.class,  BoolErrRecord.class,  BottomMarginRecord.class,  BoundSheetRecord.class,  CalcCountRecord.class,  CalcModeRecord.class,  CFHeaderRecord.class,  CFHeader12Record.class,  CFRuleRecord.class,  CFRule12Record.class,  ChartRecord.class,  ChartTitleFormatRecord.class,  CodepageRecord.class,  ColumnInfoRecord.class,  ContinueRecord.class,  CountryRecord.class,  CRNCountRecord.class,  CRNRecord.class,  DateWindow1904Record.class,  DBCellRecord.class,  DConRefRecord.class,  DefaultColWidthRecord.class,  DefaultRowHeightRecord.class,  DeltaRecord.class,  DimensionsRecord.class,  DrawingGroupRecord.class,  DrawingRecord.class,  DrawingSelectionRecord.class,  DSFRecord.class,  DVALRecord.class,  DVRecord.class,  EOFRecord.class,  ExtendedFormatRecord.class,  ExternalNameRecord.class,  ExternSheetRecord.class,  ExtSSTRecord.class,  FeatRecord.class,  FeatHdrRecord.class,  FilePassRecord.class,  FileSharingRecord.class,  FnGroupCountRecord.class,  FontRecord.class,  FooterRecord.class,  FormatRecord.class,  FormulaRecord.class,  GridsetRecord.class,  GutsRecord.class,  HCenterRecord.class,  HeaderRecord.class,  HeaderFooterRecord.class,  HideObjRecord.class,  HorizontalPageBreakRecord.class,  HyperlinkRecord.class,  IndexRecord.class,  InterfaceEndRecord.class,  InterfaceHdrRecord.class,  IterationRecord.class,  LabelRecord.class,  LabelSSTRecord.class,  LeftMarginRecord.class,  LegendRecord.class,  MergeCellsRecord.class,  MMSRecord.class,  MulBlankRecord.class,  MulRKRecord.class,  NameRecord.class,  NameCommentRecord.class,  NoteRecord.class,  NumberRecord.class,  ObjectProtectRecord.class,  ObjRecord.class,  PaletteRecord.class,  PaneRecord.class,  PasswordRecord.class,  PasswordRev4Record.class,  PrecisionRecord.class,  PrintGridlinesRecord.class,  PrintHeadersRecord.class,  PrintSetupRecord.class,  ProtectionRev4Record.class,  ProtectRecord.class,  RecalcIdRecord.class,  RefModeRecord.class,  RefreshAllRecord.class,  RightMarginRecord.class,  RKRecord.class,  RowRecord.class,  SaveRecalcRecord.class,  ScenarioProtectRecord.class,  SelectionRecord.class,  SeriesRecord.class,  SeriesTextRecord.class,  SharedFormulaRecord.class,  SSTRecord.class,  StringRecord.class,  StyleRecord.class,  SupBookRecord.class,  TabIdRecord.class,  TableRecord.class,  TableStylesRecord.class,  TextObjectRecord.class,  TopMarginRecord.class,  UncalcedRecord.class,  UseSelFSRecord.class,  UserSViewBegin.class,  UserSViewEnd.class,  ValueRangeRecord.class,  VCenterRecord.class,  VerticalPageBreakRecord.class,  WindowOneRecord.class,  WindowProtectRecord.class,  WindowTwoRecord.class,  WriteAccessRecord.class,  WriteProtectRecord.class,  WSBoolRecord.class,  // chart records  BeginRecord.class,  ChartFRTInfoRecord.class,  ChartStartBlockRecord.class,  ChartEndBlockRecord.class,  // TODO ChartFormatRecord.class,  ChartStartObjectRecord.class,  ChartEndObjectRecord.class,  CatLabRecord.class,  DataFormatRecord.class,  EndRecord.class,  LinkedDataRecord.class,  SeriesToChartGroupRecord.class,  // pivot table records  DataItemRecord.class,  ExtendedPivotTableViewFieldsRecord.class,  PageItemRecord.class,  StreamIDRecord.class,  ViewDefinitionRecord.class,  ViewFieldsRecord.class,  ViewSourceRecord.class,
};  

五. Workbook解析步骤

5.1 BOFRecord / EOFRecord

1.位置：org.apache.poi.hssf.record.BOFRecord、org.apache.poi.hssf.record.EOFRecord

2.BOFRecord表示Workbook或一个sheet的开始，EOFRecord表示Workbook或一个sheet的结尾

3.如图：

5.2 FormatRecord

5.3 ExtendedFormatRecord

1. 单元格样式索引：XFIndex
2. 单元格边框样式：border
3. 单元格水平垂直样式：alignment
4. 单元格填充色：fill

5.4 BoundSheetRecord

5.5 SSTRecord

1.位置：org.apache.poi.hssf.record.SSTRecord

2.SSTRecord中存储了在Excel中文本单元格中的文本值，文本单元格通过索引获取文本值

3.如图

六. WorkSheet解析步骤

6.1 BOFRecord/EOFRecord

6.2 DimensionsRecord

1.位置：org.apache.poi.hssf.record.DimensionsRecord

2.DimensionsRecord存储了一个sheet的行列范围

3.如图

6.3 ColumnInfoRecord

1.位置：org.apache.poi.hssf.record.ColumnInfoRecord

2.ColumnInfoRecord存储了sheet中一列的信息

3.如图：

6.4 RowRecord

6.5 LabelSSTRecord

1. 位置：org.apache.poi.hssf.record.LabelSSTRecord

2. LabelSSTRecord记录了一个sheet中的文本单元格

3. 如图：

BOFRecord.sid,               // HSSFWorkbook、HSSFSheet的开始
EOFRecord.sid,              // HSSFWorkbook、HSSFSheet的结束
BoundSheetRecord.sid,       // BoundSheetRecord记录了sheetName
SSTRecord.sid,              // SSTRecord记录了所有Sheet的文本单元格的文本
DimensionsRecord.sid,       // DimensionsRecord记录了每个Sheet的有效起始结束行列索引
MergeCellsRecord.sid,       // MergeCellsRecord记录了每个Sheet中的合并单元格信息
ExtendedFormatRecord.sid,   // ExtendedFormatRecord记录了扩展的单元格样式
FormatRecord.sid,           // FormatRecord记录单元格样式信息
ColumnInfoRecord.sid,       // ColumnInfoRecord记录了Sheet中列信息，如列是否隐藏
RowRecord.sid,              // RowRecord记录了Sheet中行信息，如行索引，行是否隐藏
BlankRecord.sid,            // Sheet中空单元格，存在单元格样式
BoolErrRecord.sid,          // Sheet中布尔或错误单元格
FormulaRecord.sid,          // Sheet中公式单元格
LabelSSTRecord.sid,         // Sheet中文本单元格
NumberRecord.sid            // Sheet中数值单元格：数字单元格和日期单元格

7.2 org.apache.poi.poifs.filesystem.POIFSFileSystem类

1. 根据fs可以获取到根目录条目DirectoryNode - root entry
2. 根目录root entry根据Entry实体名Workbook获取对应的Entry
3. 根据Workbook Entry创建该实体的输入流DocumentInputStream - ds
4. 解析输入流ds，根据Excel XLS文档格式解析为各种Record
5. 解析到设置监听器的Record，触发监听器时间listener，处理Record

/ xls文件的输入流
FileInputStream fin = newFileInputStream("C:\\Users\\Administrator\\Desktop\\测试.xls");
// 创建一个POIFSFileSystem实例
POIFSFileSystem poifs = newPOIFSFileSystem(fin);
// 从流中获取Excel的WorkBook流
InputStream workBookInputStream = poifs.createDocumentInputStream("Workbook");

7.4 org.apache.poi.hssf.eventusermodel.HSSFRequest