fix issue-1663. Skip fill when variable does not exit.

src/main/java/com/alibaba/excel/write/executor/ExcelWriteFillExecutor.java

@@ -188,6 +188,11 @@ public class ExcelWriteFillExecutor extends AbstractExcelWriteExecutor {
         WriteSheetHolder writeSheetHolder = writeContext.writeSheetHolder();
         Map<String, ExcelContentProperty> fieldNameContentPropertyMap =
             writeContext.currentWriteHolder().excelWriteHeadProperty().getFieldNameContentPropertyMap();
+
+        if (analysisCellList == null ){
+            return;
+        }
+
         for (AnalysisCell analysisCell : analysisCellList) {
             Cell cell = getOneCell(analysisCell, fillConfig);
             if (analysisCell.getOnlyOneVariable()) {

src/test/java/com/alibaba/easyexcel/test/temp/issue1663/FillData.java

@@ -0,0 +1,9 @@
+package com.alibaba.easyexcel.test.temp.issue1663;
+
+import lombok.Data;
+
+@Data
+public class FillData {
+    private String name;
+    private double number;
+}

src/test/java/com/alibaba/easyexcel/test/temp/issue1663/FillTest.java

@@ -0,0 +1,47 @@
+package com.alibaba.easyexcel.test.temp.issue1663;
+
+import com.alibaba.easyexcel.test.demo.fill.FillData;
+import com.alibaba.easyexcel.test.util.TestFileUtil;
+import com.alibaba.excel.EasyExcel;
+import com.alibaba.excel.ExcelWriter;
+import com.alibaba.excel.enums.WriteDirectionEnum;
+import com.alibaba.excel.write.metadata.WriteSheet;
+import com.alibaba.excel.write.metadata.fill.FillConfig;
+import com.alibaba.excel.write.metadata.fill.FillWrapper;
+import org.junit.Test;
+
+import java.io.File;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+public class FillTest {
+    @Test
+    public void TestFillNullPoint(){
+        String templateFileName =
+            TestFileUtil.getPath() + "issue1663" + File.separator + "template.xlsx";
+
+        String fileName = TestFileUtil.getPath() + "issue1663" + File.separator + "issue1663.xlsx";
+        ExcelWriter excelWriter = EasyExcel.write(fileName).withTemplate(templateFileName).build();
+        WriteSheet writeSheet = EasyExcel.writerSheet().build();
+        FillConfig fillConfig = FillConfig.builder().direction(WriteDirectionEnum.VERTICAL).build();
+        excelWriter.fill(new FillWrapper("data1", data()), fillConfig, writeSheet);
+
+        Map<String, Object> map = new HashMap<String, Object>();
+        // Variable {date} does not exist in the template.xlsx, which should be ignored instead of reporting an error.
+        map.put("date", "2019年10月9日13:28:28");
+        excelWriter.fill(map, writeSheet);
+        excelWriter.finish();
+    }
+    private List<com.alibaba.easyexcel.test.demo.fill.FillData> data() {
+        List<com.alibaba.easyexcel.test.demo.fill.FillData> list = new ArrayList<com.alibaba.easyexcel.test.demo.fill.FillData>();
+        for (int i = 0; i < 10; i++) {
+            com.alibaba.easyexcel.test.demo.fill.FillData fillData = new FillData();
+            list.add(fillData);
+            fillData.setName("张三");
+            fillData.setNumber(5.2);
+        }
+        return list;
+    }
+}