Optimize LuckyExcel xlsx preview conversion with Web Worker (#766)

* Optimize LuckyExcel conversion with worker

* Fallback LuckyExcel worker errors to main thread

server/src/main/resources/static/xlsx/luckyexcel-worker.js

@@ -0,0 +1,54 @@
+// LuckyExcel's bundled getBinaryContent reads window.XMLHttpRequest.
+// Web Worker exposes XMLHttpRequest on self, so provide a minimal window alias
+// before loading the UMD bundle.
+self.window = self;
+
+importScripts('./luckyexcel.umd.js');
+
+self.console.log = function () {};
+
+self.onmessage = function (event) {
+    var data = event.data || {};
+    var url = data.url;
+    var name = data.name;
+
+    if (!url) {
+        self.postMessage({
+            type: 'error',
+            message: '文件URL为空'
+        });
+        return;
+    }
+
+    try {
+        LuckyExcel.transformExcelToLuckyByUrl(
+            url,
+            name,
+            function (exportJson, luckysheetfile) {
+                if (!exportJson || !exportJson.sheets || exportJson.sheets.length === 0) {
+                    self.postMessage({
+                        type: 'error',
+                        message: '读取excel文件内容失败!'
+                    });
+                    return;
+                }
+
+                self.postMessage({
+                    type: 'success',
+                    exportJson: exportJson
+                });
+            },
+            function (error) {
+                self.postMessage({
+                    type: 'error',
+                    message: error && error.message ? error.message : String(error)
+                });
+            }
+        );
+    } catch (error) {
+        self.postMessage({
+            type: 'error',
+            message: error && error.message ? error.message : String(error)
+        });
+    }
+};

server/src/main/resources/static/xlsx/luckyexcel.umd.js

@@ -3938,7 +3938,7 @@ var LuckySheet = /** @class */function (_super) {
     _this.sheetList = allFileOption.sheetList;
     _this.imageList = allFileOption.imageList;
     _this.hide = allFileOption.hide;
-    console.log(allFileOption, 'allFileOption');
+    // console.log(allFileOption, 'allFileOption');
     _this.dataVerificationSelectCount = allFileOption.dataVerificationSelectCount;
     //Output
     _this.name = sheetName;

server/src/main/resources/web/officeweb.ftl

@@ -225,8 +225,11 @@
             // 使用异步方式加载
             await new Promise(resolve => setTimeout(resolve, 100)); // 给UI更新一点时间
 
-            // 或者使用现有的同步方法，但放在setTimeout中避免阻塞
-            await transformWithTimeout(value, name);
+            const exportJson = await transformWithWorker(value, name);
+
+            updateProgress(80);
+
+            await createLuckysheet(exportJson);
 
             updateProgress(100);
 
@@ -243,23 +246,81 @@
         }
     }
 
-    // 使用setTimeout将同步任务拆分
-    function transformWithTimeout(value, name) {
+    function transformWithWorker(value, name) {
         return new Promise((resolve, reject) => {
             updateProgress(50);
 
-            // 将转换过程放在setTimeout中，避免阻塞主线程
-            setTimeout(() => {
+            if (!window.Worker) {
+                transformOnMainThread(value, name, resolve, reject);
+                return;
+            }
+
+            let worker;
+            try {
+                worker = new Worker('xlsx/luckyexcel-worker.js');
+            } catch (error) {
+                transformOnMainThread(value, name, resolve, reject);
+                return;
+            }
+
+            let settled = false;
+            const fallbackToMainThread = function(error) {
+                if (settled) {
+                    return;
+                }
+                settled = true;
+                worker.terminate();
+                if (error) {
+                    console.warn('Excel Worker转换失败，回退主线程转换:', error);
+                }
+                transformOnMainThread(value, name, resolve, reject);
+            };
+
+            worker.onmessage = function(event) {
+                const data = event.data || {};
+
+                if (data.type === 'success') {
+                    settled = true;
+                    worker.terminate();
+                    resolve(data.exportJson);
+                    return;
+                }
+
+                if (data.type === 'error') {
+                    fallbackToMainThread(data.message || 'Excel转换失败');
+                }
+            };
+
+            worker.onerror = function(error) {
+                fallbackToMainThread(error && error.message ? error.message : error);
+            };
+
+            worker.postMessage({
+                url: value,
+                name: name
+            });
+        });
+    }
+
+    function transformOnMainThread(value, name, resolve, reject) {
         try {
             LuckyExcel.transformExcelToLuckyByUrl(value, name, function(exportJson, luckysheetfile) {
-                        if(exportJson.sheets==null || exportJson.sheets.length==0){
+                if (!exportJson || !exportJson.sheets || exportJson.sheets.length === 0) {
                     reject(new Error("读取excel文件内容失败!"));
                     return;
                 }
 
-                        updateProgress(80);
+                resolve(exportJson);
+            }, function(error) {
+                reject(error);
+            });
+        } catch (error) {
+            reject(error);
+        }
+    }
 
-                        // 使用requestAnimationFrame来更新UI，避免阻塞
+    function createLuckysheet(exportJson) {
+        return new Promise((resolve, reject) => {
             requestAnimationFrame(() => {
                 try {
                     window.luckysheet.destroy();
@@ -305,12 +366,6 @@
                 }
             });
         });
-                    
-                } catch (error) {
-                    reject(error);
-                }
-            }, 100);
-        });
     }
 
     // 页面加载完成后开始异步加载