JAVA接口

当然也可以返回void方法。

    @RequestMapping("/download")
    public String fileDownLoad(HttpServletResponse response, @RequestParam("fileName") String fileName){
        File file = new File(downloadFilePath +'/'+ fileName);
        if(!file.exists()){
            return "下载文件不存在";
        }
        response.reset();
        response.setContentType("application/octet-stream");
        response.setCharacterEncoding("utf-8");
        response.setContentLength((int) file.length());
        response.setHeader("Content-Disposition", "attachment;filename=" + fileName );

        try(BufferedInputStream bis = new BufferedInputStream(new FileInputStream(file));) {
            byte[] buff = new byte[1024];
            OutputStream os  = response.getOutputStream();
            int i = 0;
            while ((i = bis.read(buff)) != -1) {
                os.write(buff, 0, i);
                os.flush();
            }
        } catch (IOException e) {
           e.printStackTrace();
            return "下载失败";
        }
        return "下载成功";
    }

vue的下载处理

Axios接口添加返回类型：

getDownload:function({filename}){
    var param={
        fileName : fileName
    };
    return Axios.post('/api/common/getDownload', param, {response:'blob'});
}

vue前端调用a标签下载：

apis.common.getDownload(param).then((data)=>{
    if(data){
        let dataBlob = new Blob([data.data]);
        if(dataBlob.size > 0){
            let link = document.createElement("a");
            link.style.display = 'none';
            link.href = window.URL.createObjectURL(dataBlob);
            link.setAttribute("download", rowData.fileName);
            document.body.appendChild(link);
            link.click();
            URL.revokeObjectURL(link.href);
            document.body.removeChild(link);
            this.$message({message: '下载成功', type: 'success'});
        }else{
            this.$message({message: '下载失败，文件不存在', type: 'error'});
        }
    }else{
        this.$message({message: '下载异常，请重试', type: 'error'});
    }
})