Base64 码常见操作 (url 链接文件转 base64 编码、本地文件转 base64 编码等)

    <dependency>      <groupId>cn.hutool</groupId>      <artifactId>hutool-all</artifactId>      <version>5.4.3</version>    </dependency>
    <dependency>      <groupId>org.apache.httpcomponents</groupId>      <artifactId>httpclient</artifactId>      <version>4.5.10</version>    </dependency>
    <dependency>      <groupId>commons-io</groupId>      <artifactId>commons-io</artifactId>      <version>2.5</version>    </dependency>

  public static String file(String url){    String encode = null;    try {      CloseableHttpClient client = HttpClients.createDefault();      HttpGet get = new HttpGet(url);      CloseableHttpResponse response = client.execute(get);      //文件流      HttpEntity httpEntity = response.getEntity();      InputStream inStream = httpEntity.getContent();      byte[] bytes = IOUtils.toByteArray(inStream);      //附件base64      encode = cn.hutool.core.codec.Base64.encode(bytes);    } catch (IOException e) {      log.error(e.getMessage(), e);    }    return encode;  }

    /**     * 测试下载远程url的文件，转换成base64编码     * @throws Exception     */    @Test    public void testUrlFileToBase64() throws Exception {        String BASE64Str = Base64Util.file("https://xxx.oss-cn-hangzhou.aliyuncs.com/upload/20220513/165242342M");        System.out.println("BASE64Str:"+BASE64Str);    }

  public static String fileToBase64(File file) {    try {      byte[] imageData = FileUtils.readFileToByteArray(file);      String base64 = encodeImage(imageData);      return base64;    } catch (Exception e) {      log.error(e.getMessage(), e);      return null;    }  }

  public static String encodeImage(byte[] imageData) {    String encodeStr = Base64.getEncoder().encodeToString(imageData);    log.info("encodeImage>>" + encodeStr);    return encodeStr;  }

  public static boolean isBase64(String str) {    String base64Pattern = "^([A-Za-z0-9+/]{4})*([A-Za-z0-9+/]{4}|[A-Za-z0-9+/]{3}=|[A-Za-z0-9+/]{2}==)$";    return Pattern.matches(base64Pattern, str);  }

//方式一：jdk的工具类javax.xml.bind.DatatypeConverterString str = "base64字符串";//byte[]转base64String encode = DatatypeConverter.printBase64Binary(str.getBytes());System.out.println("转base64后："+encode);//Base64转byte[]byte[] decode= DatatypeConverter.parseBase64Binary(encode);System.out.println("base64转回："+new String(decode));

//方式二：jdk的工具类sun.misc.BASE64Decoder和sun.misc.BASE64Encoder//byte[]转base64BASE64Encoder base64Encoder = new BASE64Encoder();String encode1 = base64Encoder.encode(str.getBytes());System.out.println("转base64后："+encode1);//Base64转byte[]BASE64Decoder base64Decoder = new BASE64Decoder();byte[] decodeBuffer = base64Decoder.decodeBuffer(encode1);System.out.println("base64转回："+new String(decodeBuffer));