* 根据文件流解析，由抛出异常改为，默认识别为csv

easyexcel-core/src/main/java/com/alibaba/excel/support/ExcelTypeEnum.java

@@ -23,10 +23,12 @@ public enum ExcelTypeEnum {
      * csv
      */
     CSV(".csv", new byte[] {-27, -89, -109, -27}),
+
     /**
      * xls
      */
     XLS(".xls", new byte[] {-48, -49, 17, -32, -95, -79, 26, -31}),
+
     /**
      * xlsx
      */
@@ -96,13 +98,11 @@ public enum ExcelTypeEnum {
         byte[] data = IOUtils.peekFirstNBytes(inputStream, MAX_PATTERN_LENGTH);
         if (findMagic(XLSX.magic, data)) {
             return XLSX;
-        } else if (findMagic(CSV.magic, data)) {
-            return CSV;
         } else if (findMagic(XLS.magic, data)) {
             return XLS;
         }
-        throw new ExcelCommonException(
-            "Convert excel format exception.You can try specifying the 'excelType' yourself");
+        // csv has no fixed prefix, if the format is not specified, it defaults to csv
+        return CSV;
     }
 
     private static boolean findMagic(byte[] expected, byte[] actual) {

easyexcel-core/src/main/java/com/alibaba/excel/util/ClassUtils.java

@@ -431,13 +431,12 @@ public class ClassUtils {
         }
     }
 
-    private static Map<Integer, FieldWrapper> buildSortedAllFieldMap(Map<Integer, List<FieldWrapper>> orderFieldMap,
-        Map<Integer, FieldWrapper> indexFieldMap) {
+    private static Map<Integer, FieldWrapper> buildSortedAllFieldMap(Map<Integer, List<FieldWrapper>> orderFieldMap, Map<Integer, FieldWrapper> indexFieldMap) {
 
-        Map<Integer, FieldWrapper> sortedAllFieldMap = MapUtils.newHashMapWithExpectedSize(
-            orderFieldMap.size() + indexFieldMap.size());
+        Map<Integer, FieldWrapper> sortedAllFieldMap = new HashMap<>(
+            (orderFieldMap.size() + indexFieldMap.size()) * 4 / 3 + 1);
 
-        Map<Integer, FieldWrapper> tempIndexFieldMap = MapUtils.newLinkedHashMapWithExpectedSize(indexFieldMap.size());
+        Map<Integer, FieldWrapper> tempIndexFieldMap = new HashMap<>(indexFieldMap);
         int index = 0;
         for (List<FieldWrapper> fieldList : orderFieldMap.values()) {
             for (FieldWrapper field : fieldList) {

easyexcel-support/pom.xml

@@ -21,6 +21,7 @@
         <dependency>
             <groupId>org.springframework</groupId>
             <artifactId>spring-core</artifactId>
+            <version>5.3.27</version>
             <exclusions>
                 <exclusion>
                     <groupId>org.springframework</groupId>

easyexcel-test/pom.xml

@@ -40,6 +40,11 @@
             <artifactId>spring-boot-starter-test</artifactId>
             <version>2.7.11</version>
         </dependency>
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <version>4.13.2</version>
+        </dependency>
 
         <!-- logback -->
         <dependency>

update.md

@@ -7,9 +7,11 @@
 * 在`easyexcel-parent` 包中移除测试包的`dependencyManagement`
 * 删除`org.apache.poi.hssf.usermodel.PoiUtils.java`,
   使用反射获取 [Issue #2804](https://github.com/alibaba/easyexcel/issues/2804)
-* 默认对象反射缓存改成`ThreadLocal`,并支持设置反射缓存类型 [Issue #2792](https://github.com/alibaba/easyexcel/issues/2792)
+* 默认对象反射缓存改成`ThreadLocal`
+  ,并支持设置反射缓存类型 [Issue #2792](https://github.com/alibaba/easyexcel/issues/2792)
 * 支持根据`includeColumnIndexes`和`includeColumnFieldNames`
   排序 [Issue #2697](https://github.com/alibaba/easyexcel/issues/2697)
+* 根据文件流解析，由抛出异常改为，默认识别为csv
 
 # 3.2.1