java web 如何實現文件的下載 前臺和後臺

//這是html中的一部分 下載按鈕

<button type="button" id="btn" class="layui-btn">下載
					</button>

//以下是js代碼  點擊按鈕的時候調用

  $("#btn").on('click',function () {

        postDownLoadFile({
            url : base_url + "/file/download", //這裏寫後臺請求的url
            data :{
                params1:params1, //這裏可以選擇自己要傳遞的參數
				params2:params2
           
			},
            method : 'post'
        });
    });
//後臺返回成功後回填的數據
    var postDownLoadFile = function(options) {
        var config = $.extend(true, {
            method : 'post'
        }, options);
        var $iframe = $('<iframe id="down-file-iframe" />');
        var $form = $('<form target="down-file-iframe" method="' + config.method + '" />');
        $form.attr('action', config.url);
        for ( var key in config.data) {
            $form
                .append('<input type="hidden" name="' + key + '" value="' + config.data[key] + '" />');
        }
        $iframe.append($form);
        $(document.body).append($iframe);
        $form[0].submit();
        $iframe.remove();
    }

以下是後臺代碼

@RestController
@RequestMapping("/file")
public class DownloadController1 {

    //業務上需要的參數可以如param1 傳遞
    @RequestMapping(value = "/download")
    public Map<String, Object> download(HttpServletRequest request, HttpServletResponse response,String param1,String param2 ) throws Exception {

        String realName = "第一節（2）.zip"; //文件在瀏覽器的顯示位置
        String downLoadPath = ""; //這個參數表示文件在服務器的存儲路徑
        String contentType = "application/octet-stream";
        try {

            response.setContentType("text/html;charset=UTF-8");
            request.setCharacterEncoding("UTF-8");
            BufferedInputStream bis = null;
            BufferedOutputStream bos = null;

            long fileLength = new File(downLoadPath).length();

            response.setContentType(contentType);
            response.setHeader("Content-disposition",
                    "attachment; filename=" + new String(realName.getBytes("utf-8"), "ISO8859-1"));
            response.setHeader("Content-Length", String.valueOf(fileLength));

            bis = new BufferedInputStream(new FileInputStream(downLoadPath));
            bos = new BufferedOutputStream(response.getOutputStream());
            byte[] buff = new byte[2048];
            int bytesRead;
            while (-1 != (bytesRead = bis.read(buff, 0, buff.length))) {
                bos.write(buff, 0, bytesRead);
            }
            bis.close();
            bos.close();
            return ResultUtil.put(ConstantUtil.REQUEST_SUCCESS, "", "");
        } catch (Exception e) {
            return ResultUtil.put(ConstantUtil.REQUEST_FAIL, "", "");
        }


    }


}

 

 

後臺成功返回後，瀏覽器如下圖顯示，點擊下載就可以了

 

前端部分參考的這位大兄弟，在此感謝。

https://blog.csdn.net/xuxie13/article/details/82145099