几个做ppt的网站知乎,wordpress-move,汕头汽配网站建设,四川盼之网络科技官网读取连接中文件流和页面展示base64编码的文件 背景需求从接口处获取base64编码的字节流依赖java 代码 前端展示pdf图片 背景需求
我需要展示一个pdf 文件在页面上#xff0c;但是我一直没办法将 pdf的下载链接用预览方式展示出来#xff0c;于是打算讨个巧#xff0c;直接给… 读取连接中文件流和页面展示base64编码的文件 背景需求从接口处获取base64编码的字节流依赖java 代码 前端展示pdf图片 背景需求
我需要展示一个pdf 文件在页面上但是我一直没办法将 pdf的下载链接用预览方式展示出来于是打算讨个巧直接给前端页面发送 Base64 编码的字符串用来展示pdf文件。而正好我们的文件也有一个获取流的接口。于是变出现了这篇文章。
从接口处获取base64编码的字节流
依赖 dependencygroupIdorg.apache.hadoop/groupIdartifactIdhadoop-common/artifactIdversion3.4.0/version/dependencyjava 代码
直接从 URL 获取流 public static String downloadFile3(String UrlFilePath, String localFilePath) {URL url null;HttpURLConnection httpUrl null;try {url new URL(UrlFilePath);httpUrl (HttpURLConnection) url.openConnection();// 设置请求方式默认是GET// httpUrl.setRequestMethod(POST);httpUrl.connect();try (BufferedInputStream bis new BufferedInputStream(httpUrl.getInputStream())) {byte[] bytes IOUtils.toByteArray(bis);String base64String Base64.getEncoder().encodeToString(bytes);// Write the BASE64 encoded string to the filetry (BufferedWriter writer new BufferedWriter(new FileWriter(localFilePath))) {writer.write(base64String);}return base64String;}} catch (Exception e) {e.printStackTrace();}return ;}发送 GET 请求 获取流
/*** param url 远程文件路径* return base64 编码字符串*/public static String byGet(String url) {// 创建Httpclient对象CloseableHttpClient httpclient HttpClientBuilder.create().build();RequestConfig requestConfig RequestConfig.custom().setConnectTimeout(30000).setConnectionRequestTimeout(30000).setSocketTimeout(30000).build();String resultString ;CloseableHttpResponse response null;try {URIBuilder builder new URIBuilder(url);URI uri builder.build();// 创建http GET请求HttpGet httpGet new HttpGet(uri);httpGet.setConfig(requestConfig);httpGet.addHeader(Content-type, application/json; charsetutf-8);// 执行请求response httpclient.execute(httpGet);// 判断返回状态是否为200if (response.getStatusLine().getStatusCode() 200) {InputStream inputStream response.getEntity().getContent();byte[] bytes IOUtils.toByteArray(inputStream);BASE64Encoder encoder new BASE64Encoder();resultString encoder.encode(bytes);return resultString;}} catch (Exception e) {} finally {try {if (response ! null) {response.close();}httpclient.close();} catch (IOException e) {e.printStackTrace();}}return ;}前端展示
pdf function viewPdf (content) {const blob this.base64ToBlob(content)if (window.navigator window.navigator.msSaveOrOpenBlob) {window.navigator.msSaveOrOpenBlob(blob)} else {const fileURL URL.createObjectURL(blob)window.open(fileURL)}}function base64ToBlob (code) {code code.replace(/[\n\r]/g, )const raw window.atob(code)const rawLength raw.lengthconst uInt8Array new Uint8Array(rawLength)for (let i 0; i rawLength; i) {uInt8Array[i] raw.charCodeAt(i)}return new Blob([uInt8Array], { type: application/pdf })}图片
let ImgURL \img src\data:image/png;base64, content \;将拼接好的 ImgURL 拼接即可
