java调用百度AI实现图文识别功能

Myth丶恋晨 2022-12-18 12:54 243阅读 0赞

## 一、创建百度应用 ##

1、在浏览器输入网址[https://login.bce.baidu.com/][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：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3NDkzNTU2_size_16_color_FFFFFF_t_70_pic_center]

2、点击创建应用  
创建完应用后，才能获取百度AI的授权  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3NDkzNTU2_size_16_color_FFFFFF_t_70_pic_center 1]  
3、创建完成后可查看相应API key和Secret Key

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3NDkzNTU2_size_16_color_FFFFFF_t_70_pic_center 2]

## 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][https_cloud.baidu.com_doc_OCR_index.html]，如图  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3NDkzNTU2_size_16_color_FFFFFF_t_70_pic_center 3]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3NDkzNTU2_size_16_color_FFFFFF_t_70_pic_center 4]  
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 ###

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3NDkzNTU2_size_16_color_FFFFFF_t_70_pic_center 5]

[https_login.bce.baidu.com]: https://login.bce.baidu.com/
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3NDkzNTU2_size_16_color_FFFFFF_t_70_pic_center]: /images/20221122/c522e227cec64914b58b0e3388701161.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3NDkzNTU2_size_16_color_FFFFFF_t_70_pic_center 1]: /images/20221122/e1b90f58bbfd439290753dcc119db4d5.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3NDkzNTU2_size_16_color_FFFFFF_t_70_pic_center 2]: /images/20221122/e9086145ab194ac9ac580386aa7279a5.png
[https_cloud.baidu.com_doc_OCR_index.html]: https://cloud.baidu.com/doc/OCR/index.html
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3NDkzNTU2_size_16_color_FFFFFF_t_70_pic_center 3]: /images/20221122/846ff32b2bc44555aae451d729a53b03.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3NDkzNTU2_size_16_color_FFFFFF_t_70_pic_center 4]: /images/20221122/550fd0aef68d4ddca70c75be99bd283e.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM3NDkzNTU2_size_16_color_FFFFFF_t_70_pic_center 5]: /images/20221122/036542fb31d34406a3c6ba88e563bb30.png