refactor: 导出功能支持可选字段

agt-framework/agt-spring-boot-starter-excel/src/main/java/org/agt/framework/excel/core/util/ExcelUtils.java

@@ -1,15 +1,16 @@
 package org.agt.framework.excel.core.util;
 
-import org.agt.framework.common.util.http.HttpUtils;
-import org.agt.framework.excel.core.handler.SelectSheetWriteHandler;
 import com.alibaba.excel.EasyExcel;
 import com.alibaba.excel.converters.longconverter.LongStringConverter;
 import com.alibaba.excel.write.style.column.LongestMatchColumnWidthStyleStrategy;
 import jakarta.servlet.http.HttpServletResponse;
+import org.agt.framework.common.util.http.HttpUtils;
+import org.agt.framework.excel.core.handler.SelectSheetWriteHandler;
 import org.springframework.web.multipart.MultipartFile;
 
 import java.io.IOException;
 import java.util.List;
+import java.util.Set;
 
 /**
  * Excel 工具类
@@ -43,6 +44,21 @@ public class ExcelUtils {
         response.setContentType("application/vnd.ms-excel;charset=UTF-8");
     }
 
+    public static <T> void writeSelected(HttpServletResponse response, String filename, String sheetName,
+                                         Class<T> head, List<T> data, Set<String> includeColumnFieldNames) throws IOException {
+        // 输出 Excel
+        EasyExcel.write(response.getOutputStream(), head)
+                .autoCloseStream(false) // 不要自动关闭，交给 Servlet 自己处理
+                .registerWriteHandler(new LongestMatchColumnWidthStyleStrategy()) // 基于 column 长度，自动适配。最大 255 宽度
+                .registerWriteHandler(new SelectSheetWriteHandler(head)) // 基于固定 sheet 实现下拉框
+                .registerConverter(new LongStringConverter()) // 避免 Long 类型丢失精度
+                .includeColumnFieldNames(includeColumnFieldNames)
+                .sheet(sheetName).doWrite(data);
+        // 设置 header 和 contentType。写在最后的原因是，避免报错时，响应 contentType 已经被修改了
+        response.addHeader("Content-Disposition", "attachment;filename=" + HttpUtils.encodeUtf8(filename));
+        response.setContentType("application/vnd.ms-excel;charset=UTF-8");
+    }
+
     public static <T> List<T> read(MultipartFile file, Class<T> head) throws IOException {
         return EasyExcel.read(file.getInputStream(), head, null)
                 .autoCloseStream(false)  // 不要自动关闭，交给 Servlet 自己处理