kevinfu2 · February 14, 2020 13:00 · Dec 6, 2013 · Dec 5, 2013
diff --git a/mergeExcel.java b/mergeExcel.java
@@ -0,0 +1,97 @@
+  public static void mergeExcelFiles(File file, List<FileInputStream> list) throws IOException {
+    HSSFWorkbook book = new HSSFWorkbook();
+    HSSFSheet sheet = book.createSheet(file.getName());
+
+    for (FileInputStream fin : list) {
+      HSSFWorkbook b = new HSSFWorkbook(fin);
+      for (int i = 0; i < b.getNumberOfSheets(); i++) {
+        copySheets(book, sheet, b.getSheetAt(i));
+      }
+    }
+
+    try {
+      writeFile(book, file);
+    } catch (Exception e) {
+      // TODO Auto-generated catch block
+      e.printStackTrace();
+    }
+  }
+
+  protected static void writeFile(HSSFWorkbook book, File file) throws Exception {
+    FileOutputStream out = new FileOutputStream(file);
+    book.write(out);
+    out.close();
+  }
+
+  private static void copySheets(HSSFWorkbook newWorkbook, HSSFSheet newSheet, HSSFSheet sheet){     
+    copySheets(newWorkbook, newSheet, sheet, true);
+  }     
+
+  private static void copySheets(HSSFWorkbook newWorkbook, HSSFSheet newSheet, HSSFSheet sheet, boolean copyStyle){     
+    int newRownumber = newSheet.getLastRowNum() + 1;
+    int maxColumnNum = 0;     
+    Map<Integer, HSSFCellStyle> styleMap = (copyStyle) ? new HashMap<Integer, HSSFCellStyle>() : null;    
+
+    for (int i = sheet.getFirstRowNum(); i <= sheet.getLastRowNum(); i++) {     
+      HSSFRow srcRow = sheet.getRow(i);     
+      HSSFRow destRow = newSheet.createRow(i + newRownumber);     
+      if (srcRow != null) {     
+        copyRow(newWorkbook, sheet, newSheet, srcRow, destRow, styleMap);     
+        if (srcRow.getLastCellNum() > maxColumnNum) {     
+            maxColumnNum = srcRow.getLastCellNum();     
+        }     
+      }     
+    }     
+    for (int i = 0; i <= maxColumnNum; i++) {     
+      newSheet.setColumnWidth(i, sheet.getColumnWidth(i));     
+    }     
+  }     
+
+  public static void copyRow(HSSFWorkbook newWorkbook, HSSFSheet srcSheet, HSSFSheet destSheet, HSSFRow srcRow, HSSFRow destRow, Map<Integer, HSSFCellStyle> styleMap) {     
+    destRow.setHeight(srcRow.getHeight());
+    for (int j = srcRow.getFirstCellNum(); j <= srcRow.getLastCellNum(); j++) {     
+      HSSFCell oldCell = srcRow.getCell(j);
+      HSSFCell newCell = destRow.getCell(j);
+      if (oldCell != null) {     
+        if (newCell == null) {     
+          newCell = destRow.createCell(j);     
+        }     
+        copyCell(newWorkbook, oldCell, newCell, styleMap);
+      }     
+    }                
+  }
+
+  public static void copyCell(HSSFWorkbook newWorkbook, HSSFCell oldCell, HSSFCell newCell, Map<Integer, HSSFCellStyle> styleMap) {      
+    if(styleMap != null) {     
+      int stHashCode = oldCell.getCellStyle().hashCode();     
+      HSSFCellStyle newCellStyle = styleMap.get(stHashCode);     
+      if(newCellStyle == null){     
+        newCellStyle = newWorkbook.createCellStyle();     
+        newCellStyle.cloneStyleFrom(oldCell.getCellStyle());     
+        styleMap.put(stHashCode, newCellStyle);     
+      }     
+      newCell.setCellStyle(newCellStyle);   
+    }     
+    switch(oldCell.getCellType()) {     
+      case HSSFCell.CELL_TYPE_STRING:     
+        newCell.setCellValue(oldCell.getRichStringCellValue());     
+        break;     
+      case HSSFCell.CELL_TYPE_NUMERIC:     
+        newCell.setCellValue(oldCell.getNumericCellValue());     
+        break;     
+      case HSSFCell.CELL_TYPE_BLANK:     
+        newCell.setCellType(HSSFCell.CELL_TYPE_BLANK);     
+        break;     
+      case HSSFCell.CELL_TYPE_BOOLEAN:     
+        newCell.setCellValue(oldCell.getBooleanCellValue());     
+        break;     
+      case HSSFCell.CELL_TYPE_ERROR:     
+        newCell.setCellErrorValue(oldCell.getErrorCellValue());     
+        break;     
+      case HSSFCell.CELL_TYPE_FORMULA:     
+        newCell.setCellFormula(oldCell.getCellFormula());     
+        break;     
+      default:     
+        break;     
+    }
+  }