后端接口返回流文件，前端请求接口并实现下载功能

1、设置接口response返回类型 responseType: 'blob'

fetchResourceDownLoad(opt) {
        return Vue.http.post(`${baseUrl}/userResource/download`, opt, { responseType: 'blob' });
    },

2、请求接口，创建a链接进行下载

download(params) {
            const options = {
                resourceId: params.resourceId,
            };
            fetchResourceDownLoad(options).then((res) => {
                const a = document.createElement('a');
                const fileName = params.fileName;
                if ('download' in a) {
                    a.download = fileName;
                    a.style.display = 'none';
                    a.href = window.URL.createObjectURL(res.body);
                    document.body.appendChild(a);
                    a.click();
                    URL.revokeObjectURL(a.href);
                    document.body.removeChild(a);
                }
            });
        },