如何在ajax成功下载excel文件

Question

我正在使用ajax在客户端下载excel文件。文件已下载，但采用加密代码。我到目前为止尝试过如下：

servlet端的代码：

response.setContentType("application/vnd.ms-excel");
response.setHeader("Content-Disposition", "attachment; filename=ErrorDocument.xls");
System.out.println("session get : " + (request.getSession().getAttribute("errorFile") instanceof Workbook));

try {
    Workbook errorWorkbook = new HSSFWorkbook();
    errorWorkbook = (Workbook) request.getSession().getAttribute("errorFile");
    java.io.OutputStream out = response.getOutputStream();
    errorWorkbook.write(out);
    out.close();
} 
catch (Exception e) {
    e.printStackTrace();
}

JavaScript代码：

$.ajax({
    url:'errorFileDownload',
    method:'post',
    dataType: "text",
    success: function(response, status, xhr) {
        console.log("In success of file download.");
        if(response!=""){
            // check for a filename
            var filename = "";
            var disposition = xhr.getResponseHeader('Content-Disposition');
            if (disposition && disposition.indexOf('attachment') !== -1) {
                var filenameRegex = /filename[^;=\n]*=((['"]).*?\2|[^;\n]*)/;
                var matches = filenameRegex.exec(disposition);
                if (matches != null && matches[1]) filename = matches[1].replace(/['"]/g, '');
            }

            var type = xhr.getResponseHeader('Content-Type');
            console.log("Content-type :" + type);
            var blob = new Blob([response], { type: type });

            if (typeof window.navigator.msSaveBlob !== 'undefined') {
                // IE workaround for "HTML7007: One or more blob URLs were revoked by closing the blob for which they were created. These URLs will no longer resolve as the data backing the URL has been freed."
                window.navigator.msSaveBlob(blob, filename);
            } else {
                var URL = window.URL || window.webkitURL;
                var downloadUrl = URL.createObjectURL(blob);

                if (filename) {
                    // use HTML5 a[download] attribute to specify filename
                    var a = document.createElement("a");
                    // safari doesn't support this yet
                    if (typeof a.download === 'undefined') {
                        window.location = downloadUrl;
                    } else {
                        a.href = downloadUrl;
                        a.download = filename;
                        document.body.appendChild(a);
                        a.click();
                    }
                } else {
                    window.location = downloadUrl;
                }

                setTimeout(function () { URL.revokeObjectURL(downloadUrl); }, 100); // cleanup
            }
        } else {
            alert("file is not available");
        }
    },
    error:function(){
        alert("error occure here...");
    }
});