淘寶按圖搜索商品（拍立淘）Java 爬蟲實戰指南

在電商領域，按圖搜索商品功能為用戶提供了更直觀、便捷的購物體驗。淘寶的拍立淘功能更是憑借其強大的圖像識別技術，成為許多開發者和商家關注的焦點。本文將詳細介紹如何利用 Java 爬蟲技術實現淘寶按圖搜索商品功能，包括注冊賬號、上傳圖片、調用 API 及解析響應等關鍵步驟。

一、準備工作

（一）注冊淘寶開放平臺賬號

在使用淘寶按圖搜索功能之前，需要在淘寶開放平臺注冊賬號并創建應用。注冊成功后，平臺會分配一個 App Key和 App Secret，這兩個參數是調用 API 時的身份驗證憑證。

（二）添加 Maven 依賴

為了方便地發送 HTTP 請求和解析 JSON 數據，需要在項目中添加以下 Maven 依賴：

xml

<dependencies><dependency><groupId>org.apache.httpcomponents</groupId><artifactId>httpclient</artifactId><version>4.5.13</version></dependency><dependency><groupId>com.fasterxml.jackson.core</groupId><artifactId>jackson-databind</artifactId><version>2.10.0</version></dependency>
</dependencies>

二、代碼實現

（一）生成簽名

淘寶 API 接口需要對請求參數進行簽名驗證。以下是一個生成簽名的 Java 方法示例：

java

import java.security.MessageDigest;
import java.util.TreeMap;public class ApiUtil {public static String generateSign(TreeMap<String, String> params, String appSecret) {StringBuilder signStr = new StringBuilder();for (Map.Entry<String, String> entry : params.entrySet()) {signStr.append(entry.getKey()).append(entry.getValue());}signStr.insert(0, appSecret).append(appSecret);return md5(signStr.toString()).toUpperCase();}public static String md5(String input) {try {MessageDigest md = MessageDigest.getInstance("MD5");byte[] array = md.digest(input.getBytes());StringBuilder sb = new StringBuilder();for (byte b : array) {sb.append(String.format("%02x", b));}return sb.toString();} catch (Exception e) {throw new RuntimeException(e);}}
}

（二）上傳圖片并獲取圖片標識

由于 API 接口要求傳入圖片的 URL 或 ID，因此需要先將圖片上傳到淘寶的圖片空間或其他支持的圖片服務器。以下是使用 Java 上傳圖片到淘寶服務器的代碼示例：

java

import org.apache.http.HttpEntity;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.ContentType;
import org.apache.http.entity.mime.MultipartEntityBuilder;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;import java.io.File;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;public class ImageUploader {private static final String UPLOAD_URL = "https://restapi.taobao.com/router/rest";public static String uploadImage(String appKey, String appSecret, String imagePath) throws IOException {File imageFile = new File(imagePath);if (!imageFile.exists()) {throw new IllegalArgumentException("Image file does not exist");}Map<String, String> params = new HashMap<>();params.put("app_key", appKey);params.put("method", "taobao.upload.img");params.put("format", "json");params.put("v", "2.0");params.put("sign_method", "md5");params.put("timestamp", String.valueOf(System.currentTimeMillis() / 1000));String sign = ApiUtil.generateSign(new TreeMap<>(params), appSecret);params.put("sign", sign);try (CloseableHttpClient httpClient = HttpClients.createDefault()) {HttpPost httpPost = new HttpPost(UPLOAD_URL);MultipartEntityBuilder builder = MultipartEntityBuilder.create();for (Map.Entry<String, String> entry : params.entrySet()) {builder.addTextBody(entry.getKey(), entry.getValue(), ContentType.TEXT_PLAIN);}builder.addBinaryBody("file", imageFile, ContentType.APPLICATION_OCTET_STREAM, imageFile.getName());HttpEntity entity = builder.build();httpPost.setEntity(entity);try (CloseableHttpResponse response = httpClient.execute(httpPost)) {if (response.getStatusLine().getStatusCode() == 200) {String jsonResponse = EntityUtils.toString(response.getEntity());// 解析返回的 JSON 數據，獲取圖片 URL// 這里假設返回的 JSON 中包含字段 "pic_url"return parsePicUrlFromResponse(jsonResponse);} else {throw new RuntimeException("Failed to upload image, status code: " + response.getStatusLine().getStatusCode());}}}}private static String parsePicUrlFromResponse(String jsonResponse) {// 解析 JSON 數據，提取圖片 URL// 這里假設返回的 JSON 中包含字段 "pic_url"// 實際開發中，根據 API 返回的 JSON 結構進行解析return jsonResponse;}
}

（三）調用按圖搜索接口

在成功上傳圖片并獲取圖片標識后，接下來就可以調用淘寶的按圖搜索接口。以下是調用接口的 Java 示例代碼：

java

import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;import java.io.IOException;
import java.util.TreeMap;public class TaobaoImageSearch {private static final String SEARCH_URL = "https://eco.taobao.com/router/rest";public static String searchItemsByImage(String appKey, String appSecret, String imageUrl) throws IOException {TreeMap<String, String> params = new TreeMap<>();params.put("app_key", appKey);params.put("method", "taobao.item.search.img");params.put("format", "json");params.put("v", "2.0");params.put("sign_method", "md5");params.put("timestamp", String.valueOf(System.currentTimeMillis() / 1000));params.put("img_url", imageUrl);String sign = ApiUtil.generateSign(params, appSecret);params.put("sign", sign);StringBuilder urlBuilder = new StringBuilder(SEARCH_URL);for (Map.Entry<String, String> entry : params.entrySet()) {if (urlBuilder.length() > SEARCH_URL.length()) {urlBuilder.append("&");}urlBuilder.append(entry.getKey()).append("=").append(entry.getValue());}try (CloseableHttpClient httpClient = HttpClients.createDefault()) {HttpGet httpGet = new HttpGet(urlBuilder.toString());try (CloseableHttpResponse response = httpClient.execute(httpGet)) {if (response.getStatusLine().getStatusCode() == 200) {return EntityUtils.toString(response.getEntity());} else {throw new RuntimeException("Failed to search items, status code: " + response.getStatusLine().getStatusCode());}}}}
}

（四）解析響應數據

調用按圖搜索接口后，淘寶會返回一個 JSON 格式的響應數據。以下是一個解析響應數據的 Java 示例代碼：

java

import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;import java.io.IOException;public class ResponseParser {public static void parseResponse(String jsonResponse) throws IOException {ObjectMapper objectMapper = new ObjectMapper();JsonNode rootNode = objectMapper.readTree(jsonResponse);JsonNode itemsNode = rootNode.path("items");if (itemsNode.isArray()) {for (JsonNode itemNode : itemsNode) {String title = itemNode.path("title").asText();String price = itemNode.path("price").asText();String picUrl = itemNode.path("pic_url").asText();String detailUrl = itemNode.path("detail_url").asText();System.out.println("商品標題: " + title);System.out.println("商品價格: " + price);System.out.println("商品圖片: " + picUrl);System.out.println("商品鏈接: " + detailUrl);System.out.println("----------");}} else {System.out.println("No items found");}}
}

三、完整流程示例

以下是一個完整的 Java 示例，展示了如何上傳圖片并調用淘寶按圖搜索接口：

java

import java.io.IOException;public class Main {public static void main(String[] args) {String appKey = "your_app_key";String appSecret = "your_app_secret";String imagePath = "path/to/your/image.jpg";try {// 上傳圖片并獲取圖片 URLString imageUrl = ImageUploader.uploadImage(appKey, appSecret, imagePath);System.out.println("圖片上傳成功，圖片 URL: " + imageUrl);// 調用按圖搜索接口String jsonResponse = TaobaoImageSearch.searchItemsByImage(appKey, appSecret, imageUrl);System.out.println("搜索結果: " + jsonResponse);// 解析響應數據ResponseParser.parseResponse(jsonResponse);} catch (IOException e) {e.printStackTrace();}}
}