diff --git a/exporter-addon/src/main/java/org/vaadin/haijian/CSVFileBuilder.java b/exporter-addon/src/main/java/org/vaadin/haijian/CSVFileBuilder.java
index d9b39e5..2c70794 100644
--- a/exporter-addon/src/main/java/org/vaadin/haijian/CSVFileBuilder.java
+++ b/exporter-addon/src/main/java/org/vaadin/haijian/CSVFileBuilder.java
@@ -8,11 +8,11 @@
 import java.io.IOException;
 
 public class CSVFileBuilder<T> extends FileBuilder<T> {
-    private FileWriter writer;
+    protected FileWriter writer;
     private int rowNr;
     private int colNr;
 
-    CSVFileBuilder(Grid<T> grid, ExporterOption option) {
+    protected CSVFileBuilder(Grid<T> grid, ExporterOption option) {
         super(grid, option);
     }
 
diff --git a/exporter-addon/src/main/java/org/vaadin/haijian/ExcelFileBuilder.java b/exporter-addon/src/main/java/org/vaadin/haijian/ExcelFileBuilder.java
index 263726e..ee30be1 100644
--- a/exporter-addon/src/main/java/org/vaadin/haijian/ExcelFileBuilder.java
+++ b/exporter-addon/src/main/java/org/vaadin/haijian/ExcelFileBuilder.java
@@ -18,10 +18,10 @@ public class ExcelFileBuilder<T> extends FileBuilder<T> {
     private int rowNr;
     private int colNr;
     private Row row;
-    private Cell cell;
+    protected Cell cell;
     private CellStyle boldStyle;
-
-    ExcelFileBuilder(Grid<T> grid, ExporterOption option) {
+  
+    protected ExcelFileBuilder(Grid<T> grid, ExporterOption option) {
         super(grid, option);
     }
 
diff --git a/exporter-addon/src/main/java/org/vaadin/haijian/FileBuilder.java b/exporter-addon/src/main/java/org/vaadin/haijian/FileBuilder.java
index 46c763a..8500b79 100644
--- a/exporter-addon/src/main/java/org/vaadin/haijian/FileBuilder.java
+++ b/exporter-addon/src/main/java/org/vaadin/haijian/FileBuilder.java
@@ -30,7 +30,7 @@ public abstract class FileBuilder<T> {
     private boolean headerRowBuilt = false;
     private ExporterOption option;
 
-    FileBuilder(Grid<T> grid, ExporterOption option) {
+    protected FileBuilder(Grid<T> grid, ExporterOption option) {
         this.grid = grid;
         columns = grid.getColumns().stream().filter(this::isExportable).collect(Collectors.toList());
         if (columns.isEmpty()) {
@@ -44,7 +44,7 @@ private boolean isExportable(Grid.Column column) {
                 && (propertySet == null || propertySet.getProperty(column.getId()).isPresent());
     }
 
-    InputStream build() {
+    protected InputStream build() {
         try {
             initTempFile();
             resetContent();
@@ -136,7 +136,11 @@ private void buildRow(T item) {
             Optional<PropertyDefinition<T, ?>> propertyDefinition = propertySet.getProperty(column.getId());
             if (propertyDefinition.isPresent()) {
                 onNewCell();
-                buildCell(propertyDefinition.get().getGetter().apply(item));
+                if(column.getValueProvider() != null) {
+                    buildCell( column.getValueProvider().apply(item) );
+                } else {
+                    buildCell(propertyDefinition.get().getGetter().apply(item));
+                }
             } else {
                 throw new ExporterException("Column id: " + column.getId() + " is a property which cannot be found");
             }
@@ -182,4 +186,5 @@ private Stream<T> getDataStream(Query newQuery) {
         }
         return stream;
     }
+
 }