漏写了一行.

mybatis-plus-extension/src/main/java/com/baomidou/mybatisplus/extension/service/impl/ServiceImpl.java

@@ -194,6 +194,7 @@ public class ServiceImpl<M extends BaseMapper<T>, T> implements IService<T> {
                 } else {
                     throw ExceptionUtils.mpe("Error:  Can not execute. Could not find @TableId.");
                 }
+                batchSqlSession.flushStatements();
             }
         }
         return true;