diff --git a/easyexcel-core/src/main/java/com/alibaba/excel/metadata/csv/CsvWorkbook.java b/easyexcel-core/src/main/java/com/alibaba/excel/metadata/csv/CsvWorkbook.java
index d2f0e08b..56f995ba 100644
--- a/easyexcel-core/src/main/java/com/alibaba/excel/metadata/csv/CsvWorkbook.java
+++ b/easyexcel-core/src/main/java/com/alibaba/excel/metadata/csv/CsvWorkbook.java
@@ -12,17 +12,10 @@ import lombok.Getter;
 import lombok.Setter;
 import org.apache.commons.compress.utils.Lists;
 import org.apache.poi.ss.SpreadsheetVersion;
+import org.apache.poi.ss.formula.EvaluationWorkbook;
 import org.apache.poi.ss.formula.udf.UDFFinder;
-import org.apache.poi.ss.usermodel.CellStyle;
-import org.apache.poi.ss.usermodel.CreationHelper;
-import org.apache.poi.ss.usermodel.DataFormat;
-import org.apache.poi.ss.usermodel.Font;
-import org.apache.poi.ss.usermodel.Name;
-import org.apache.poi.ss.usermodel.PictureData;
+import org.apache.poi.ss.usermodel.*;
 import org.apache.poi.ss.usermodel.Row.MissingCellPolicy;
-import org.apache.poi.ss.usermodel.Sheet;
-import org.apache.poi.ss.usermodel.SheetVisibility;
-import org.apache.poi.ss.usermodel.Workbook;
 
 /**
  * csv workbook
@@ -200,7 +193,7 @@ public class CsvWorkbook implements Workbook {
     }
 
     @Override
-    public short getNumberOfFonts() {
+    public int getNumberOfFonts() {
         return 0;
     }
 
@@ -209,10 +202,6 @@ public class CsvWorkbook implements Workbook {
         return 0;
     }
 
-    @Override
-    public Font getFontAt(short idx) {
-        return null;
-    }
 
     @Override
     public Font getFontAt(int idx) {
@@ -272,31 +261,12 @@ public class CsvWorkbook implements Workbook {
         return null;
     }
 
-    @Override
-    public Name getNameAt(int nameIndex) {
-        return null;
-    }
 
     @Override
     public Name createName() {
         return null;
     }
 
-    @Override
-    public int getNameIndex(String name) {
-        return 0;
-    }
-
-    @Override
-    public void removeName(int index) {
-
-    }
-
-    @Override
-    public void removeName(String name) {
-
-    }
-
     @Override
     public void removeName(Name name) {
 
@@ -421,6 +391,21 @@ public class CsvWorkbook implements Workbook {
         return 0;
     }
 
+    @Override
+    public EvaluationWorkbook createEvaluationWorkbook() {
+        return null;
+    }
+
+    @Override
+    public CellReferenceType getCellReferenceType() {
+        return null;
+    }
+
+    @Override
+    public void setCellReferenceType(CellReferenceType cellReferenceType) {
+
+    }
+
     @Override
     public Iterator<Sheet> iterator() {
         return null;