java 将File文件转换为base64编码 举个栗子

// File文件转换为base64编码
1 public static String encodeBase64File() throws Exception {
    File file = new File("D:\\镜像包\\反光衣图片001391.jpg");
    FileInputStream inputFile = new FileInputStream(file);
    byte[] buffer = new byte[(int)file.length()];
    inputFile.read(buffer);
    inputFile.close();
    return new BASE64Encoder().encode(buffer);
}

服务调用示例：

 public static void main(String[] args) throws Exception {
        File file = new File("D:\\镜像包\\反光衣图片\\001391.jpg");
        //file文件转换为base64编码
        FileInputStream inputFile = new FileInputStream(file);
        byte[] buffer = new byte[(int)file.length()];
        inputFile.read(buffer);
        inputFile.close();
        String base =  new BASE64Encoder().encode(buffer);
        //封装参数
        Map<String, Object> paramMap = new HashMap<>();
        paramMap.put("image", base);
        paramMap.put("image_type", "BASE64");
        String baseurl = "http://114.116.125.146:5001";
        String url = baseurl + "/rest/1.0/demo";
        try {

            System.out.println(paramMap);

            //RestTemplate 实例化过程发现默认的RestTemplate 只支持application/json格式，所以需要手动补充text/html格式
            RestTemplate restTemplate = new RestTemplate();
            MappingJackson2HttpMessageConverter mappingJackson2HttpMessageConverter = new MappingJackson2HttpMessageConverter();
            mappingJackson2HttpMessageConverter.setSupportedMediaTypes(Arrays.asList(
                    MediaType.TEXT_HTML,
                    MediaType.TEXT_PLAIN));
            restTemplate.getMessageConverters().add(mappingJackson2HttpMessageConverter);
            //识别
            ResponseEntity<net.sf.json.JSONObject> responseEntity = restTemplate.postForEntity(url, paramMap, net.sf.json.JSONObject.class);
            net.sf.json.JSONObject jsonObject = responseEntity.getBody();
            String result = jsonObject.getString("result");
        } catch (Exception e) {
            e.printStackTrace();
        }
    }