feat add Excel工具类支持更灵活的自定义导出方式，以便用户分批处理导出数据

ruoyi-common/ruoyi-common-excel/src/main/java/org/dromara/common/excel/utils/ExcelUtil.java

@@ -27,6 +27,7 @@ import java.io.UnsupportedEncodingException;
 import java.util.Collection;
 import java.util.List;
 import java.util.Map;
+import java.util.function.Consumer;
 
 /**
  * Excel相关处理
@@ -203,6 +204,45 @@ public class ExcelUtil {
         builder.doWrite(list);
     }
 
+    /**
+     * 导出excel
+     *
+     * @param headType 带Excel注解的类型
+     * @param os       输出流
+     * @param options  Excel下拉可选项
+     * @param consumer 导出助手消费函数
+     */
+    public static <T> void exportExcel(Class<T> headType, OutputStream os, List<DropDownOptions> options, Consumer<ExcelWriterHelper> consumer) {
+        try (ExcelWriter writer = FastExcel.write(os, headType)
+            .autoCloseStream(false)
+            // 自动适配
+            .registerWriteHandler(new LongestMatchColumnWidthStyleStrategy())
+            // 大数值自动转换 防止失真
+            .registerConverter(new ExcelBigNumberConvert())
+            // 批注必填项处理
+            .registerWriteHandler(new DataWriteHandler(headType))
+            // 添加下拉框操作
+            .registerWriteHandler(new ExcelDownHandler(options))
+            .build()) {
+            ExcelWriterHelper helper = ExcelWriterHelper.of(writer);
+            // 执行消费函数
+            consumer.accept(helper);
+        } catch (Exception e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    /**
+     * 导出excel
+     *
+     * @param headType 带Excel注解的类型
+     * @param os       输出流
+     * @param consumer 导出助手消费函数
+     */
+    public static <T> void exportExcel(Class<T> headType, OutputStream os, Consumer<ExcelWriterHelper> consumer) {
+        exportExcel(headType, os, null, consumer);
+    }
+
     /**
      * 单表多数据模板导出 模板格式为 {.属性}
      *

ruoyi-common/ruoyi-common-excel/src/main/java/org/dromara/common/excel/utils/ExcelWriterHelper.java

@@ -0,0 +1,135 @@
+package org.dromara.common.excel.utils;
+
+import cn.idev.excel.ExcelWriter;
+import cn.idev.excel.FastExcel;
+import cn.idev.excel.context.WriteContext;
+import cn.idev.excel.write.builder.ExcelWriterSheetBuilder;
+import cn.idev.excel.write.builder.ExcelWriterTableBuilder;
+import cn.idev.excel.write.metadata.WriteSheet;
+import cn.idev.excel.write.metadata.WriteTable;
+import cn.idev.excel.write.metadata.fill.FillConfig;
+import lombok.AccessLevel;
+import lombok.Getter;
+import lombok.RequiredArgsConstructor;
+
+import java.util.Collection;
+import java.util.function.Supplier;
+
+/**
+ * ExcelWriterHelper Excel写出助手
+ * <br>
+ * 提供了一组与 ExcelWriter 一一对应的写出方法，避免直接提供 ExcelWriter 而导致的一些不可控问题（比如提前关闭了IO流等）
+ *
+ *
+ * @see ExcelWriter
+ * @author 秋辞未寒
+ */
+@RequiredArgsConstructor
+public class ExcelWriterHelper {
+
+    @Getter(AccessLevel.PRIVATE)
+    private final ExcelWriter excelWriter;
+
+    public void write(Collection<?> data, WriteSheet writeSheet) {
+        excelWriter.write(data, writeSheet);
+    }
+
+    public void write(Supplier<Collection<?>> supplier, WriteSheet writeSheet) {
+        excelWriter.write(supplier, writeSheet);
+    }
+
+    public void write(Collection<?> data, WriteSheet writeSheet, WriteTable writeTable) {
+        excelWriter.write(data, writeSheet, writeTable);
+    }
+
+    public void write(Supplier<Collection<?>> supplier, WriteSheet writeSheet, WriteTable writeTable) {
+        excelWriter.write(supplier.get(), writeSheet, writeTable);
+    }
+
+    public void fill(Object data, WriteSheet writeSheet) {
+        excelWriter.fill(data, writeSheet);
+    }
+
+    public void fill(Object data, FillConfig fillConfig, WriteSheet writeSheet) {
+        excelWriter.fill(data, fillConfig, writeSheet);
+    }
+
+    public void fill(Supplier<Object> supplier, WriteSheet writeSheet) {
+        excelWriter.fill(supplier, writeSheet);
+    }
+
+    public void fill(Supplier<Object> supplier, FillConfig fillConfig, WriteSheet writeSheet) {
+        excelWriter.fill(supplier, fillConfig, writeSheet);
+    }
+
+    public WriteContext writeContext() {
+        return excelWriter.writeContext();
+    }
+
+    /**
+     * 创建一个 ExcelWriterHelper
+     *
+     * @param excelWriter ExcelWriter
+     * @return ExcelWriterHelper
+     */
+    public static ExcelWriterHelper of(ExcelWriter excelWriter) {
+        return new ExcelWriterHelper(excelWriter);
+    }
+
+    // -------------------------------- sheet start
+
+    public static WriteSheet buildSheet(Integer sheetNo, String sheetName) {
+        return sheetBuilder(sheetNo, sheetName).build();
+    }
+
+    public static WriteSheet buildSheet(Integer sheetNo) {
+        return sheetBuilder(sheetNo).build();
+    }
+
+    public static WriteSheet buildSheet(String sheetName) {
+        return sheetBuilder(sheetName).build();
+    }
+
+    public static WriteSheet buildSheet() {
+        return sheetBuilder().build();
+    }
+
+    public static ExcelWriterSheetBuilder sheetBuilder(Integer sheetNo, String sheetName) {
+        return FastExcel.writerSheet(sheetNo, sheetName);
+    }
+
+    public static ExcelWriterSheetBuilder sheetBuilder(Integer sheetNo) {
+        return FastExcel.writerSheet(sheetNo);
+    }
+
+    public static ExcelWriterSheetBuilder sheetBuilder(String sheetName) {
+        return FastExcel.writerSheet(sheetName);
+    }
+
+    public static ExcelWriterSheetBuilder sheetBuilder() {
+        return FastExcel.writerSheet();
+    }
+
+    // -------------------------------- sheet end
+
+    // -------------------------------- table start
+
+    public static WriteTable buildTable(Integer tableNo) {
+        return tableBuilder(tableNo).build();
+    }
+
+    public static WriteTable buildTable() {
+        return tableBuilder().build();
+    }
+
+    public static ExcelWriterTableBuilder tableBuilder(Integer tableNo) {
+        return FastExcel.writerTable(tableNo);
+    }
+
+    public static ExcelWriterTableBuilder tableBuilder() {
+        return FastExcel.writerTable();
+    }
+
+    // -------------------------------- table end
+
+}