From 9ca65038caf899cc9479b9bf5945bda2e50e13a3 Mon Sep 17 00:00:00 2001
From: Jiaju Zhuang <zhuangjiaju@qq.com>
Date: Fri, 13 Jan 2023 16:31:00 +0800
Subject: [PATCH] =?UTF-8?q?=E6=96=B0=E5=A2=9E=E6=A1=88=E4=BE=8B?=
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---
 .../easyexcel/test/demo/rare/WriteTest.java   | 87 +++++++++++++++++++
 1 file changed, 87 insertions(+)
 create mode 100644 easyexcel-test/src/test/java/com/alibaba/easyexcel/test/demo/rare/WriteTest.java

diff --git a/easyexcel-test/src/test/java/com/alibaba/easyexcel/test/demo/rare/WriteTest.java b/easyexcel-test/src/test/java/com/alibaba/easyexcel/test/demo/rare/WriteTest.java
new file mode 100644
index 00000000..a2384da6
--- /dev/null
+++ b/easyexcel-test/src/test/java/com/alibaba/easyexcel/test/demo/rare/WriteTest.java
@@ -0,0 +1,87 @@
+package com.alibaba.easyexcel.test.demo.rare;
+
+import java.io.File;
+import java.util.Date;
+import java.util.List;
+
+import com.alibaba.easyexcel.test.demo.write.DemoData;
+import com.alibaba.easyexcel.test.util.TestFileUtil;
+import com.alibaba.excel.EasyExcel;
+import com.alibaba.excel.ExcelWriter;
+import com.alibaba.excel.util.FileUtils;
+import com.alibaba.excel.util.ListUtils;
+import com.alibaba.excel.write.handler.WorkbookWriteHandler;
+import com.alibaba.excel.write.handler.context.WorkbookWriteHandlerContext;
+import com.alibaba.excel.write.metadata.WriteSheet;
+
+import lombok.extern.slf4j.Slf4j;
+import org.apache.poi.ss.usermodel.Workbook;
+import org.apache.poi.xssf.streaming.SXSSFWorkbook;
+import org.junit.Ignore;
+import org.junit.Test;
+
+/**
+ * 记录一些不太常见的案例
+ *
+ * @author Jiaju Zhuang
+ */
+@Ignore
+@Slf4j
+public class WriteTest {
+
+    /**
+     * 压缩临时文件
+     * 在导出Excel且格式为xlsx的时候会生成一个临时的xml文件，会比较大，再磁盘不太够的情况下，可以压缩。
+     * 当然压缩式耗费性能的
+     */
+    @Test
+    public void compressedTemporaryFile() {
+        log.info("临时的xml存储在:{}", FileUtils.getPoiFilesPath());
+        File file = TestFileUtil.createNewFile("rare/compressedTemporaryFile" + System.currentTimeMillis()
+            + ".xlsx");
+
+        // 这里 需要指定写用哪个class去写
+        try (ExcelWriter excelWriter = EasyExcel.write(file, DemoData.class).registerWriteHandler(
+            new WorkbookWriteHandler() {
+
+                /**
+                 * 拦截Workbook创建完成事件
+                 * @param context
+                 */
+                @Override
+                public void afterWorkbookCreate(WorkbookWriteHandlerContext context) {
+                    // 获取到Workbook对象
+                    Workbook workbook = context.getWriteWorkbookHolder().getWorkbook();
+                    // 只有SXSSFWorkbook模式才会生成临时文件
+                    if (workbook instanceof SXSSFWorkbook) {
+                        SXSSFWorkbook sxssfWorkbook = (SXSSFWorkbook)workbook;
+                        // 设置临时文件压缩，当然这个会浪费cpu性能 但是临时文件会变小
+                        sxssfWorkbook.setCompressTempFiles(true);
+                    }
+                }
+            }).build()) {
+            // 这里注意 如果同一个sheet只要创建一次
+            WriteSheet writeSheet = EasyExcel.writerSheet("模板").build();
+            // 10万数据 确保有足够的空间
+            for (int i = 0; i < 10000; i++) {
+                // 分页去数据库查询数据 这里可以去数据库查询每一页的数据
+                List<DemoData> data = data();
+                excelWriter.write(data, writeSheet);
+            }
+            log.info("写入完毕，开始准备迁移压缩文件。");
+        }
+    }
+
+    private List<DemoData> data() {
+        List<DemoData> list = ListUtils.newArrayList();
+        for (int i = 0; i < 10; i++) {
+            DemoData data = new DemoData();
+            data.setString("字符串" + i);
+            data.setDate(new Date());
+            data.setDoubleData(0.56);
+            list.add(data);
+        }
+        return list;
+    }
+
+}