add pagenumber in output json file

src/main/java/technology/tabula/Table.java

@@ -23,11 +23,18 @@ public Table(ExtractionAlgorithm extractionAlgorithm) {
 
 	private int rowCount = 0;
 	private int colCount = 0;
+	private int pageNumber = 0;
 
 	/* visible for testing */ final TreeMap<CellPosition, RectangularTextContainer> cells = new TreeMap<>();
 
 	public int getRowCount() { return rowCount; }
 	public int getColCount() { return colCount; }
+	public int getPageNumber() { 
+		return pageNumber; 
+	}
+	public void setPageNumber(int number) { 
+		pageNumber = number;
+	}
 
 	public String getExtractionMethod() { return extractionMethod; }
 

src/main/java/technology/tabula/TableWithRulingLines.java

@@ -14,12 +14,13 @@ public class TableWithRulingLines extends Table {
     List<Ruling> verticalRulings, horizontalRulings;
     RectangleSpatialIndex<Cell> si = new RectangleSpatialIndex<>();
 
-    public TableWithRulingLines(Rectangle area, List<Cell> cells, List<Ruling> horizontalRulings, List<Ruling> verticalRulings, ExtractionAlgorithm extractionAlgorithm) {
+    public TableWithRulingLines(Rectangle area, List<Cell> cells, List<Ruling> horizontalRulings, List<Ruling> verticalRulings, ExtractionAlgorithm extractionAlgorithm, int number) {
         super(extractionAlgorithm);
         this.setRect(area);
         this.verticalRulings = verticalRulings;
         this.horizontalRulings = horizontalRulings;
         this.addCells(cells);
+        this.setPageNumber(number);
     }
 
     private void addCells(List<Cell> cells) {

src/main/java/technology/tabula/extractors/BasicExtractionAlgorithm.java

@@ -65,6 +65,7 @@ public int compare(Ruling arg0, Ruling arg1) {
 
         Table table = new Table(this);
         table.setRect(page.getLeft(), page.getTop(), page.getWidth(), page.getHeight());
+        table.setPageNumber(page.getPageNumber());
 
         for (int i = 0; i < lines.size(); i++) {
             Line line = lines.get(i);

src/main/java/technology/tabula/extractors/SpreadsheetExtractionAlgorithm.java

@@ -131,7 +131,7 @@ else if (r.vertical()) {
                 }
             }
 
-            TableWithRulingLines t = new TableWithRulingLines(area, overlappingCells, horizontalOverlappingRulings, verticalOverlappingRulings, this);
+            TableWithRulingLines t = new TableWithRulingLines(area, overlappingCells, horizontalOverlappingRulings, verticalOverlappingRulings, this, page.getPageNumber());
             spreadsheets.add(t);
         }
         Utils.sort(spreadsheets, Rectangle.ILL_DEFINED_ORDER);

src/main/java/technology/tabula/json/TableSerializer.java

@@ -30,6 +30,7 @@ public JsonElement serialize(Table table, Type type, JsonSerializationContext co
         json.addProperty("height", table.getHeight());
         json.addProperty("right", table.getRight());
         json.addProperty("bottom", table.getBottom());
+        json.addProperty("page_number", table.getPageNumber());
         json.add("data", data);
 
         for (List<RectangularTextContainer> tableRow : table.getRows()) {