新增支持自定义转换器 入参可以为空 #1084

src/main/java/com/alibaba/excel/converters/NullableObjectConverter.java

+package com.alibaba.excel.converters;
+
+/**
+ * When implementing <code>convertToExcelData</code> method, pay attention to the reference <code>value</code> may be
+ * null
+ *
+ * @author JiaJu Zhuang
+ **/
+public interface NullableObjectConverter<T> extends Converter<T> {
+
+}

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

@@ -10,6 +10,7 @@ import org.apache.poi.ss.usermodel.Sheet;
 import com.alibaba.excel.context.WriteContext;
 import com.alibaba.excel.converters.Converter;
 import com.alibaba.excel.converters.ConverterKeyBuild;
+import com.alibaba.excel.converters.NullableObjectConverter;
 import com.alibaba.excel.enums.CellDataTypeEnum;
 import com.alibaba.excel.exception.ExcelDataConvertException;
 import com.alibaba.excel.metadata.CellData;
@@ -32,11 +33,10 @@ public abstract class AbstractExcelWriteExecutor implements ExcelWriteExecutor {
 
     protected CellData converterAndSet(WriteHolder currentWriteHolder, Class clazz, Cell cell, Object value,
         ExcelContentProperty excelContentProperty, Head head, Integer relativeRowIndex) {
-        if (value == null) {
-            return new CellData(CellDataTypeEnum.EMPTY);
-        }
-        if (value instanceof String && currentWriteHolder.globalConfiguration().getAutoTrim()) {
-            value = ((String)value).trim();
+        boolean needTrim =
+            value != null && (value instanceof String && currentWriteHolder.globalConfiguration().getAutoTrim());
+        if (needTrim) {
+            value = ((String) value).trim();
         }
         CellData cellData = convert(currentWriteHolder, clazz, cell, value, excelContentProperty);
         if (cellData.getFormula() != null && cellData.getFormula()) {
@@ -70,9 +70,6 @@ public abstract class AbstractExcelWriteExecutor implements ExcelWriteExecutor {
 
     protected CellData convert(WriteHolder currentWriteHolder, Class clazz, Cell cell, Object value,
         ExcelContentProperty excelContentProperty) {
-        if (value == null) {
-            return new CellData(CellDataTypeEnum.EMPTY);
-        }
         // This means that the user has defined the data.
         if (value instanceof CellData) {
             CellData cellDataValue = (CellData)value;
@@ -110,6 +107,9 @@ public abstract class AbstractExcelWriteExecutor implements ExcelWriteExecutor {
                 new CellData(CellDataTypeEnum.EMPTY), excelContentProperty,
                 "Can not find 'Converter' support class " + clazz.getSimpleName() + ".");
         }
+        if (value == null && !(converter instanceof NullableObjectConverter)) {
+            return new CellData(CellDataTypeEnum.EMPTY);
+        }
         CellData cellData;
         try {
             cellData =

src/test/java/com/alibaba/easyexcel/test/temp/read/HeadListener.java

@@ -14,7 +14,7 @@ import com.alibaba.fastjson.JSON;
  *
  * @author Jiaju Zhuang
  */
-public class HeadListener extends AnalysisEventListener<Map<Integer,String>> {
+public class HeadListener extends AnalysisEventListener<HeadReadData> {
     private static final Logger LOGGER = LoggerFactory.getLogger(HeadListener.class);
     /**
      * 每隔5条存储数据库，实际使用中可以3000条，然后清理list ，方便内存回收
@@ -29,7 +29,7 @@ public class HeadListener extends AnalysisEventListener<Map<Integer,String>> {
     }
 
     @Override
-    public void invoke(Map<Integer,String> data, AnalysisContext context) {
+    public void invoke(HeadReadData data, AnalysisContext context) {
         LOGGER.info("index:{}", context.readRowHolder().getRowIndex());
         LOGGER.info("解析到一条数据:{}", JSON.toJSONString(data));
     }

src/test/java/com/alibaba/easyexcel/test/temp/read/HeadReadData.java

@@ -11,10 +11,9 @@ import lombok.experimental.Accessors;
  * @author Jiaju Zhuang
  **/
 @Data
-@Accessors(chain = true)
 public class HeadReadData {
-    @ExcelProperty("头1")
+    @ExcelProperty({"主标题","数据1"})
     private String h1;
-    @ExcelProperty({"头", "头2"})
+    @ExcelProperty({"主标题", "数据2"})
     private String h2;
 }

src/test/java/com/alibaba/easyexcel/test/temp/read/HeadReadTest.java

@@ -32,8 +32,8 @@ public class HeadReadTest {
 
     @Test
     public void test() throws Exception {
-        File file = TestFileUtil.readUserHomeFile("test/t1.xlsx");
-        EasyExcel.read(file, null, new HeadListener()).ignoreEmptyRow(false).sheet(0).doRead();
+        File file = TestFileUtil.readUserHomeFile("test/t2.xlsx");
+        EasyExcel.read(file, HeadReadData.class, new HeadListener()).ignoreEmptyRow(false).sheet(0).doRead();
 
     }
 

update.md

@@ -2,6 +2,7 @@
 * 发布正式版
 * 修复第一行为空不会调用`invokeHeadMap`的bug [Issue #993](https://github.com/alibaba/easyexcel/issues/993)
 * 当类的属性没有按照ExcelProperty的属性index顺序排序的时候，写数据出现错乱 [Issue #1046](https://github.com/alibaba/easyexcel/issues/1046)
+* 新增支持自定义转换器 入参可以为空 实现`NullableObjectConverter` 即可  [Issue #1084](https://github.com/alibaba/easyexcel/issues/1084)
 
 # 2.2.0-beta2
 * 修复最长匹配策略不同表格会有影响的bug [Issue #1010](https://github.com/alibaba/easyexcel/issues/1010)