java调用百度AI实现图文识别功能

1 创建百度应用

1、在浏览器输入网址https://login.bce.baidu.com/或者百度搜索‘百度ai’点击第一个。点击主页的产品服务，看到文字识别。如下图所示：

2、点击创建应用 创建完应用后，才能获取百度AI的授权 3、创建完成后可查看相应API key和Secret Key

2 查看sdk文档

点击文字识别下面的技术文档https://cloud.baidu.com/doc/OCR/index.html，如图 可以根据官方提供的文档进行图文识别，下面博主为大家提供了java的工具类

3 java调用图文识别的工具类

3.1 获取access_token

import org.json.JSONObject;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
/**
 * 获取token类
 *  https://github.com/ourlang
 * @author   福小林
 */

public class AuthService {

    /**
     * 获取权限token
     * @return 返回示例：
     * {
     * "access_token": "24.460da4889caad24cccdb1fea17221975.2592000.1491995545.282335-1234567",
     * "expires_in": 2592000
     * }
     */
    public static String getAuth() {
        // 官网获取的API Key 更新为你注册的
        String clientId = "sZoHMGl0jo1pSXQ1SeWiG8kv";
        // 官网获取的 Secret Key 更新为你注册的
        String clientSecret = "FPRCv0tbhoEXjDD6Gj7XWLhg64EqAelo";
        return getAuth(clientId, clientSecret);
    }

    /**
     * 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 示例：
     * "24.460da4889caad24cccdb1fea17221975.2592000.1491995545.282335-1234567"
     */
    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();
            // 定义 BufferedReader输入流来读取URL的响应
            BufferedReader in = new BufferedReader(new InputStreamReader(connection.getInputStream()));
            StringBuilder result = new StringBuilder();
            String line;
            while ((line = in.readLine()) != null) {
                result.append(line);
            }
            JSONObject jsonObject = new JSONObject(result.toString());
            return jsonObject.getString("access_token");
        } catch (Exception e) {
            //打印错误日志
            e.printStackTrace(System.err);
        }
        return null;
    }
}

3.2 调用服务测试

import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.util.EntityUtils;

import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.URLEncoder;

/**
 * 图像文字识别公用接口类
 * https://github.com/ourlang
 * @author 福小林
 */

public class ImageTextUtil {
    /**
     * 调用百度的图文识别接口
     */
    private static final String POST_URL = "https://aip.baidubce.com/rest/2.0/ocr/v1/general_basic?access_token=" + AuthService.getAuth();

    private static final String BASE64_START_MARK = "data:image/png;base64,";

    /**
     * 根据图片的base64编码实现图文识别功能
     *
     * @param imgStr base64图片字符串
     * @return 识别结果，为json格式
     * @throws URISyntaxException URI打开异常
     * @throws IOException        io流异常
     */
    public static String getTextByBase64(String imgStr) throws URISyntaxException, IOException {
        StringBuilder sb = new StringBuilder();
        if (imgStr.startsWith(BASE64_START_MARK)){
            imgStr=imgStr.substring(22);
        }
        String[] strings = splitStringByLength(imgStr, 1000);
        for (String tempStr : strings) {
            sb.append(tempStr);
        }
        String s = encodeUriComponent(sb.toString());
        String param = "image=" + s;
        return post(param);
    }

    /**
     * @param url 图片url http地址
     * @return 识别结果，为json格式
     */
    public static String getTextByUrl(String url) throws IOException, URISyntaxException {
        String param = "url=" + url;
        return post(param);
    }

    /***
     * 将字符串按固定长度切割成字符子串
     * @param src 需要切割的字符串
     * @param length 字符子串的长度
     * @return 字符子串数组
     */
    public static String[] splitStringByLength(String src, int length) {
        //检查参数是否合法
        if (null == src || src.isEmpty()) {
            System.out.println("the string is null");
            return null;
        }
        if (length <= 0) {
            System.out.println("the length < 0");
            return null;
        }
        //获取整个字符串可以被切割成字符子串的个数
        int n = (src.length() + length - 1) / length;
        String[] split = new String[n];
        for (int i = 0; i < n; i++) {
            if (i < (n - 1)) {
                split[i] = src.substring(i * length, (i + 1) * length);
            } else {
                split[i] = src.substring(i * length);
            }
        }
        return split;
    }

    /**
     * 通过传递参数：url和image进行文字识别
     *
     * @param param 区分是url还是image识别
     * @return 识别结果
     * @throws URISyntaxException URI打开异常
     * @throws IOException        IO流异常
     */
    private static String post(String param) throws URISyntaxException, IOException {
        //开始搭建post请求
        HttpClient httpClient = new DefaultHttpClient();
        HttpPost post = new HttpPost();
        URI url = new URI(POST_URL);
        post.setURI(url);
        //设置请求头，请求头必须为application/x-www-form-urlencoded，因为是传递一个很长的字符串，不能分段发送
        post.setHeader("Content-Type", "application/x-www-form-urlencoded");
        StringEntity entity = new StringEntity(param);
        post.setEntity(entity);
        HttpResponse response = httpClient.execute(post);
        if (response.getStatusLine().getStatusCode() == 200) {
            String str;
            try {
                //读取服务器返回过来的json字符串数据
                str = EntityUtils.toString(response.getEntity());
                return str;
            } catch (Exception e) {
                e.printStackTrace();
                return null;
            }
        }
        return null;
    }

    /**
     * 返回编码后的字符串
     *
     * @param s 要编码的字符串
     * @return 编码好的字符串
     */
    public static String encodeUriComponent(String s) {
        String result;

        try {
            result = URLEncoder.encode(s, "UTF-8")
                    .replaceAll("\\+", "%20")
                    .replaceAll("\\%21", "!")
                    .replaceAll("\\%27", "'")
                    .replaceAll("\\%28", "(")
                    .replaceAll("\\%29", ")")
                    .replaceAll("\\%7E", "~");
        }
        // This exception should never occur.
        catch (UnsupportedEncodingException e) {
            result = s;
        }
        return result;
    }
    public static void main(String[] args) {
        try {
            String textByUrl = getTextByUrl("http://lsdcloud.com/img/goImage/file.png");
            System.out.println(textByUrl);
                        
        } catch (URISyntaxException | IOException e) {
            e.printStackTrace();
        }
    }
}

3.3.输出结果如下