步骤：

1. 创建OCR应用，获取API Key和Secret Key；

2. 查看接口文档，文字识别OCR (baidu.com)；

3. 编写代码；

代码如下：

1. 获取token

    /**
     * 获取API访问token
     * 该token有一定的有效期，需要自行管理，当失效时需重新获取.
     * @param ak - 百度云官网获取的 API Key
     * @param sk - 百度云官网获取的 Securet Key
     * @return assess_token
     */
    private static String getAuth(String ak, String sk) {
        // 获取token地址
        String authHost = "https://aip.baidubce.com/oauth/2.0/token?";
        String getAccessTokenUrl = authHost
                // 1. grant_type为固定参数
                + "grant_type=client_credentials"
                // 2. 官网获取的 API Key
                + "&client_id=" + ak
                // 3. 官网获取的 Secret Key
                + "&client_secret=" + sk;
        try {
            URL realUrl = new URL(getAccessTokenUrl);
            // 打开和URL之间的连接
            HttpURLConnection connection = (HttpURLConnection) realUrl.openConnection();
            connection.setRequestMethod("GET");
            connection.connect();
            // 获取所有响应头字段
            Map<String, List<String>> map = connection.getHeaderFields();
            // 遍历所有的响应头字段
            for (String key : map.keySet()) {
                System.err.println(key + "--->" + map.get(key));
            }
            // 定义 BufferedReader输入流来读取URL的响应
            BufferedReader in = new BufferedReader(new InputStreamReader(connection.getInputStream()));
            String result = "";
            String line;
            while ((line = in.readLine()) != null) {
                result += line;
            }
            /**
             * 返回结果示例
             */
            System.err.println("result:" + result);
            JSONObject jsonObject = JSONObject.parseObject(result);
            String access_token = jsonObject.getString("access_token");
            return access_token;
        } catch (Exception e) {
            System.err.printf("获取token失败！");
            e.printStackTrace(System.err);
        }
        return null;
    }

 

2. 拿上token调用ocr接口

        String access_token = getAuth("API Key", "Secret Key");
        try {
            // filePath为本地图片路径
            byte[] imgData = FileUtils.readFileByBytes(filePath);
            String imgStr = new String(Base64.encodeBase64(imgData));
            String url = "https://aip.baidubce.com/rest/2.0/ocr/v1/idcard";
            CloseableHttpClient httpclient = HttpClients.createDefault();
            try {
                HttpPost httppost = new HttpPost(url);
                StringBody accessToken = new StringBody(access_token, ContentType.TEXT_PLAIN);
                StringBody image = new StringBody(imgStr, ContentType.TEXT_PLAIN);
                StringBody id_card_side = new StringBody("front", ContentType.TEXT_PLAIN);
                HttpEntity reqEntity = MultipartEntityBuilder.create()
                        .addPart("access_token",accessToken)
                        .addPart("image",image)
                        .addPart("id_card_side",id_card_side)
                        .build();
                httppost.setEntity(reqEntity);
                System.out.println("executing request " + httppost.getRequestLine());
                CloseableHttpResponse response = httpclient.execute(httppost);
                try {
                    int statusCode = response.getStatusLine().getStatusCode();
                    HttpEntity resEntity = response.getEntity();
                    if (200 == statusCode && resEntity != null) {
                        logger.info("Response content length: {}", resEntity.getContentLength());
                        logger.info("Response content length: {}", resEntity.getContent());
                        String result = EntityUtils.toString(resEntity);
                        //打印获取到的返回值
                        logger.info("Response content: {}", result);
                        JSONObject jsonObject = JSONObject.parseObject(result);
                        JSONObject wordsResult = jsonObject.getJSONObject("words_result");
                        String name = wordsResult.getJSONObject("姓名").getString("words");
                        String nation = wordsResult.getJSONObject("民族").getString("words");
                        String address = wordsResult.getJSONObject("住址").getString("words");
                        String idCardNo = wordsResult.getJSONObject("公民身份号码").getString("words");
                        String birthDate = wordsResult.getJSONObject("出生").getString("words");
                        String sex = wordsResult.getJSONObject("性别").getString("words");
                    }
                    EntityUtils.consume(resEntity);
                } finally {
                    response.close();
                }
            } finally {
                httpclient.close();
            }
        } catch (Exception e) {
            MsgAlert.alert("系统发生错误，请联系管理员!");
        }