安卓开发利用百度识图api进行物体识别（java版）

阅读原文时间：2023年07月12日阅读：2

之前的随笔中，已经实现了python版本调用api接口，之所以使用python是因为python比java要简洁。

但是我发现在使用过程中，chaquopy插件会弹出底部toast显示“unlicensed copy of chaquopy”，也就是说使用这款插件是需要license的，如果没有配置license，软件运行5分钟会强制重启，详见https://chaquo.com/chaquopy/license/。

chaquopy对开源软件是免费的，闭源是收费的，因此正常使用就需要我们发送Email去申请一个license，有点麻烦。因此接下来再写一个java版的，首先写几个工具类：

1.获取token

import org.json.JSONObject;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.List;
import java.util.Map;

/**
* 获取token类
*/
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 = "你的API Key";
// 官网获取的 Secret Key 更新为你注册的
String clientSecret = "你的Secret Key";
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"  
 \*/  
public 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 = new JSONObject(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.Base64

/**
* Base64 工具类
*/
public class Base64Util {
private static final char last2byte = (char) Integer.parseInt("00000011", 2);
private static final char last4byte = (char) Integer.parseInt("00001111", 2);
private static final char last6byte = (char) Integer.parseInt("00111111", 2);
private static final char lead6byte = (char) Integer.parseInt("11111100", 2);
private static final char lead4byte = (char) Integer.parseInt("11110000", 2);
private static final char lead2byte = (char) Integer.parseInt("11000000", 2);
private static final char[] encodeTable = new char[]{'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '/'};

public Base64Util() {  
}

public static String encode(byte\[\] from) {  
    StringBuilder to = new StringBuilder((int) ((double) from.length \* 1.34D) + 3);  
    int num = 0;  
    char currentByte = 0;

    int i;  
    for (i = 0; i < from.length; ++i) {  
        for (num %= 8; num < 8; num += 6) {  
            switch (num) {  
                case 0:  
                    currentByte = (char) (from\[i\] & lead6byte);  
                    currentByte = (char) (currentByte >>> 2);  
                case 1:  
                case 3:  
                case 5:  
                default:  
                    break;  
                case 2:  
                    currentByte = (char) (from\[i\] & last6byte);  
                    break;  
                case 4:  
                    currentByte = (char) (from\[i\] & last4byte);  
                    currentByte = (char) (currentByte << 2);  
                    if (i + 1 < from.length) {  
                        currentByte = (char) (currentByte | (from\[i + 1\] & lead2byte) >>> 6);  
                    }  
                    break;  
                case 6:  
                    currentByte = (char) (from\[i\] & last2byte);  
                    currentByte = (char) (currentByte << 4);  
                    if (i + 1 < from.length) {  
                        currentByte = (char) (currentByte | (from\[i + 1\] & lead4byte) >>> 4);  
                    }  
            }

            to.append(encodeTable\[currentByte\]);  
        }  
    }

    if (to.length() % 4 != 0) {  
        for (i = 4 - to.length() % 4; i > 0; --i) {  
            to.append("=");  
        }  
    }

    return to.toString();  
}

}

3.FileUtil文件读取工具类

import java.io.*;

/**
* 文件读取工具类
*/
public class FileUtil {

/\*\*  
 \* 读取文件内容，作为字符串返回  
 \*/  
public static String readFileAsString(String filePath) throws IOException {  
    File file = new File(filePath);  
    if (!file.exists()) {  
        throw new FileNotFoundException(filePath);  
    } 

    if (file.length() > 1024 \* 1024 \* 1024) {  
        throw new IOException("File is too large");  
    } 

    StringBuilder sb = new StringBuilder((int) (file.length()));  
    // 创建字节输入流  
    FileInputStream fis = new FileInputStream(filePath);  
    // 创建一个长度为10240的Buffer  
    byte\[\] bbuf = new byte\[10240\];  
    // 用于保存实际读取的字节数  
    int hasRead = 0;  
    while ( (hasRead = fis.read(bbuf)) > 0 ) {  
        sb.append(new String(bbuf, 0, hasRead));  
    }  
    fis.close();  
    return sb.toString();  
}

/\*\*  
 \* 根据文件路径读取byte\[\] 数组  
 \*/  
public static byte\[\] readFileByBytes(String filePath) throws IOException {  
    File file = new File(filePath);  
    if (!file.exists()) {  
        throw new FileNotFoundException(filePath);  
    } else {  
        ByteArrayOutputStream bos = new ByteArrayOutputStream((int) file.length());  
        BufferedInputStream in = null;

        try {  
            in = new BufferedInputStream(new FileInputStream(file));  
            short bufSize = 1024;  
            byte\[\] buffer = new byte\[bufSize\];  
            int len1;  
            while (-1 != (len1 = in.read(buffer, 0, bufSize))) {  
                bos.write(buffer, 0, len1);  
            }

            byte\[\] var7 = bos.toByteArray();  
            return var7;  
        } finally {  
            try {  
                if (in != null) {  
                    in.close();  
                }  
            } catch (IOException var14) {  
                var14.printStackTrace();  
            }

            bos.close();  
        }  
    }  
}

}

4.Http工具类

import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.List;
import java.util.Map;

/**
* http 工具类
*/
public class HttpUtil {

public static String post(String requestUrl, String accessToken, String params)  
        throws Exception {  
    String contentType = "application/x-www-form-urlencoded";  
    return HttpUtil.post(requestUrl, accessToken, contentType, params);  
}

public static String post(String requestUrl, String accessToken, String contentType, String params)  
        throws Exception {  
    String encoding = "UTF-8";  
    if (requestUrl.contains("nlp")) {  
        encoding = "GBK";  
    }  
    return HttpUtil.post(requestUrl, accessToken, contentType, params, encoding);  
}

public static String post(String requestUrl, String accessToken, String contentType, String params, String encoding)  
        throws Exception {  
    String url = requestUrl + "?access\_token=" + accessToken;  
    return HttpUtil.postGeneralUrl(url, contentType, params, encoding);  
}

public static String postGeneralUrl(String generalUrl, String contentType, String params, String encoding)  
        throws Exception {  
    URL url = new URL(generalUrl);  
    // 打开和URL之间的连接  
    HttpURLConnection connection = (HttpURLConnection) url.openConnection();  
    connection.setRequestMethod("POST");  
    // 设置通用的请求属性  
    connection.setRequestProperty("Content-Type", contentType);  
    connection.setRequestProperty("Connection", "Keep-Alive");  
    connection.setUseCaches(false);  
    connection.setDoOutput(true);  
    connection.setDoInput(true);

    // 得到请求的输出流对象  
    DataOutputStream out = new DataOutputStream(connection.getOutputStream());  
    out.write(params.getBytes(encoding));  
    out.flush();  
    out.close();

    // 建立实际的连接  
    connection.connect();  
    // 获取所有响应头字段  
    Map<String, List<String>> headers = connection.getHeaderFields();  
    // 遍历所有的响应头字段  
    for (String key : headers.keySet()) {  
        System.err.println(key + "--->" + headers.get(key));  
    }  
    // 定义 BufferedReader输入流来读取URL的响应  
    BufferedReader in = null;  
    in = new BufferedReader(  
            new InputStreamReader(connection.getInputStream(), encoding));  
    String result = "";  
    String getLine;  
    while ((getLine = in.readLine()) != null) {  
        result += getLine;  
    }  
    in.close();  
    System.err.println("result:" + result);  
    return result;  
}

}

5.开始识图

import utils.AuthService;
import utils.Base64Util;
import utils.FileUtil;
import utils.HttpUtil;
//import utils.GsonUtils;
import net.sf.json.JSONArray;

import java.net.URLEncoder;

/**
* 通用物体和场景识别
*/
public class AdvancedGeneral {

/\*\*  
 \* 重要提示代码中所需工具类  
 \* FileUtil,Base64Util,HttpUtil,GsonUtils请从  
 \* https://ai.baidu.com/file/658A35ABAB2D404FBF903F64D47C1F72  
 \* https://ai.baidu.com/file/C8D81F3301E24D2892968F09AE1AD6E2  
 \* https://ai.baidu.com/file/544D677F5D4E4F17B4122FBD60DB82B3  
 \* https://ai.baidu.com/file/470B3ACCA3FE43788B5A963BF0B625F3  
 \* 下载  
 \*/  
public static String advancedGeneral() {  
    int index = 0;  
    int rIndex = 0;  
    int lastLeft = 0;  
    // 请求url  
    String url = "https://aip.baidubce.com/rest/2.0/image-classify/v2/advanced\_general";  
    try {  
        // 本地文件路径  
        String filePath = "E:\\\\Microsoft Edge Download\\\\菜品1.jpg";//文件路径  
        byte\[\] imgData = FileUtil.readFileByBytes(filePath);  
        String imgStr = Base64Util.encode(imgData);  
        String imgParam = URLEncoder.encode(imgStr, "UTF-8");

        String param = "image=" + imgParam;

        // 注意这里仅为了简化编码每一次请求都去获取access\_token，线上环境access\_token有过期时间， 客户端可自行缓存，过期后重新获取。  
        String accessToken = AuthService.getAuth();;

        String result = HttpUtil.post(url, accessToken, param);  
        System.out.println(result);

        //保留想要的结果  
        char\[\] chars = result.toCharArray();  
        for(int i = 0;i<result.length();i++){  
            if(chars\[i\] == '\['){  
                index = i;  
            }  
            if(chars\[i\] == '\]'){  
                rIndex = i+1;  
            }  
        }  
        System.out.println(result.substring(index,rIndex));

        //String转json，遍历json结果集  
        JSONArray jsonArray = JSONArray.fromObject(result.substring(index,rIndex));  
        for(int i = 0 ;i < jsonArray.size() ; i++){  
            System.out.println("score = "+jsonArray.getJSONObject(i).getString("score"));  
            System.out.println("root = "+jsonArray.getJSONObject(i).getString("root"));  
            System.out.println("keyword = "+jsonArray.getJSONObject(i).getString("keyword"));  
            break;  
        }

        return result;  
    } catch (Exception e) {  
        e.printStackTrace();  
    }  
    return null;  
}

public static void main(String\[\] args) {  
    AdvancedGeneral.advancedGeneral();  
}

}