下载excel文件后无法打开的问题

dwon() {  
            uni.showLoading({  
                title: "加载中"  
            });  
            let filePath = `${wx.env.USER_DATA_PATH}/${+new Date}.xlsx`; //导出的文件名  
            this.$re.get(`/api/equipment/download?batch_no=${this.batch_no}&diyname=${'equipment_archive'}`).then(res => {  
                console.log(res);  
                uni.getFileSystemManager().writeFile({   
                    filePath, //文件名  
                    data:res, //二进制数据  
                    encoding: 'utf8',  
                    success: res => {  
                        console.log(res);  
                        uni.hideLoading();  
                        uni.showModal({  
                            title: "下载成功",  
                            content: "是否打开?",  
                            confirmColor: "#0bc183",  
                            confirmText: "打开",  
                            success(res) {  
                                if (res.confirm) {  
                                    uni.openDocument({ //打开文件  
                                        filePath, //文件名  
                                        showMenu: true, //右上角是否显示(...)  
                                        success(res) {  
                                            console.log(res);  
                                        },  
                                    });  
                                } else if (res.cancel) {}  
                            },  
                        });  
                    },  
                    fail: err => {  
                        uni.hideLoading();  
                        uni.showModal({  
                            title: '提示',  
                            content: "文件保存失败",  
                            showCancel: false, //是否显示取消按钮  
                            success: function(result) {}  
                        });  
                        console.error('文件保存失败:', err);  
                    }  
                });  
            }).catch(err => {  
                uni.hideLoading();  
                uni.showModal({  
                    title: '提示',  
                    content: "文件下载失败",  
                    showCancel: false, //是否显示取消按钮  
                    success: function(result) {}  
                });  
                console.error('文件下载失败:', err);  
            });  
        }