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(); } }
剩下MainActivity就不写了，就是调用方法，拼接起来就行
跟python相比，java要麻烦不少，首先是需要导入一些jar包，其次代码量明显多很多