大文件案例

easyexcel-test/src/test/java/com/alibaba/easyexcel/test/demo/rare/WriteTest.java

@@ -1,8 +1,11 @@
 package com.alibaba.easyexcel.test.demo.rare;
 
 import java.io.File;
+import java.util.ArrayList;
 import java.util.Date;
+import java.util.Iterator;
 import java.util.List;
+import java.util.UUID;
 
 import com.alibaba.easyexcel.test.demo.write.DemoData;
 import com.alibaba.easyexcel.test.util.TestFileUtil;
@@ -24,6 +27,14 @@ import org.apache.poi.ss.usermodel.Row;
 import org.apache.poi.ss.usermodel.Sheet;
 import org.apache.poi.ss.usermodel.Workbook;
 import org.apache.poi.xssf.streaming.SXSSFWorkbook;
+import org.ehcache.Cache;
+import org.ehcache.Cache.Entry;
+import org.ehcache.CacheManager;
+import org.ehcache.config.CacheConfiguration;
+import org.ehcache.config.builders.CacheConfigurationBuilder;
+import org.ehcache.config.builders.CacheManagerBuilder;
+import org.ehcache.config.builders.ResourcePoolsBuilder;
+import org.ehcache.config.units.MemoryUnit;
 import org.junit.Ignore;
 import org.junit.Test;
 
@@ -46,6 +57,7 @@ public class WriteTest {
         log.info("临时的xml存储在:{}", FileUtils.getPoiFilesPath());
         File file = TestFileUtil.createNewFile("rare/compressedTemporaryFile" + System.currentTimeMillis()
             + ".xlsx");
+        log.info("写入到文件：{}", file.getAbsolutePath());
 
         // 这里 需要指定写用哪个class去写
         try (ExcelWriter excelWriter = EasyExcel.write(file, DemoData.class).registerWriteHandler(
@@ -86,6 +98,7 @@ public class WriteTest {
     public void specifiedCellWrite() {
         File file = TestFileUtil.createNewFile("rare/specifiedCellWrite" + System.currentTimeMillis()
             + ".xlsx");
+        log.info("写入到文件：{}", file.getAbsolutePath());
 
         // 需要区分是在 最后一行之前 还是之后
         // 区分的原因是：excel只能一直向前，而且内存里面只存储100条，而afterRowDispose是在每一行写入完成的时候调用，所以修改一行需要拦截这个事件
@@ -128,6 +141,63 @@ public class WriteTest {
         log.info("写入到文件完成:{}", file);
     }
 
+    /**
+     * 缓存配置
+     */
+    private static final CacheConfiguration CACHE_CONFIGURATION = CacheConfigurationBuilder
+        // 设置产品最大占用10G
+        .newCacheConfigurationBuilder(String.class, ArrayList.class,
+            ResourcePoolsBuilder.newResourcePoolsBuilder().disk(10, MemoryUnit.GB))
+        // 最大遍历深度 设置成一直遍历
+        .withSizeOfMaxObjectGraph(1000 * 1000L)
+        // 最大对象为10G数据
+        .withSizeOfMaxObjectSize(10, MemoryUnit.GB).build();
+
+    /**
+     *缓存存储文件的位置
+     */
+    private static final String CACHE_PATH = FileUtils.getTempFilePrefix() + "myCache";
+    private static final  CacheManager CACHE_MANAGER = CacheManagerBuilder.newCacheManagerBuilder()
+        // 这里名字随便取 路径放到临时目录
+        .with(CacheManagerBuilder.persistence(CACHE_PATH))
+        .build(true);
+
+    /**
+     * 在大文件后追加写入
+     * 这个是无法实现的，所以思路就是临时存储到磁盘里面，然后再读取出来一次性写入
+     */
+    @Test
+    public void appendLagreFile() {
+        log.info("临时的缓存目录是:{}", CACHE_PATH);
+
+
+
+        // 记录缓存名字
+        String cacheName = UUID.randomUUID().toString();
+        // 整个文件的要一起公用
+        Cache<String, List<DemoData>> cache = cacheManager.createCache(cacheName, cacheConfiguration);
+
+        for (int i = 0; i < 10000; i++) {
+            // 把所有需要追加的数据放到缓存里面
+            cache.put(UUID.randomUUID().toString(), data());
+        }
+
+        File file = TestFileUtil.createNewFile("rare/appendLagreFile" + System.currentTimeMillis()
+            + ".xlsx");
+        log.info("写入到文件：{}", file.getAbsolutePath());
+        // 这里 需要指定写用哪个class去写
+        try (ExcelWriter excelWriter = EasyExcel.write(file, DemoData.class).build()) {
+            // 这里注意 如果同一个sheet只要创建一次
+            WriteSheet writeSheet = EasyExcel.writerSheet("模板").build();
+            Iterator<Entry<String, List<DemoData>>> iterator = cache.iterator();
+            while (iterator.hasNext()) {
+                excelWriter.write(iterator.next().getValue(), writeSheet);
+            }
+            log.info("写入数据完毕。");
+        }
+        cacheManager.removeCache(cacheName);
+    }
+
     private List<DemoData> data() {
         List<DemoData> list = ListUtils.newArrayList();
         for (int i = 0; i < 10; i++) {

easyexcel-test/src/test/java/com/alibaba/easyexcel/test/demo/write/DemoData.java

@@ -1,5 +1,6 @@
 package com.alibaba.easyexcel.test.demo.write;
 
+import java.io.Serializable;
 import java.util.Date;
 
 import com.alibaba.excel.annotation.ExcelIgnore;
@@ -17,7 +18,7 @@ import lombok.Setter;
 @Getter
 @Setter
 @EqualsAndHashCode
-public class DemoData {
+public class DemoData implements Serializable {
     @ExcelProperty("字符串标题")
     private String string;
     @ExcelProperty("日期标题")