Enterprise Java API for Receipt OCR & Expense Parsing

// 💰 Skip the JVM memory leaks. Get 200 free credits instantly:
// 👉 https://structocr.com/register

package com.structocr.examples;

import java.io.IOException;
import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.Base64;
import com.google.gson.Gson;
import com.google.gson.JsonArray;
import com.google.gson.JsonElement;
import com.google.gson.JsonObject;

public class ReceiptOcrClient {

    public static void main(String[] args) throws IOException, InterruptedException {
        String apiKey = "YOUR_API_KEY"; // Replace with your StructOCR API key
        String imagePath = "path/to/uber_receipt.jpg"; // Path to the uploaded receipt

        // 1. Read the image file and encode it to Base64
        String base64Image = encodeFileToBase64(imagePath);

        // 2. Construct the JSON payload
        JsonObject payload = new JsonObject();
        payload.addProperty("img", base64Image);
        String jsonPayload = payload.toString();

        // 3. Create the modern HTTP client
        HttpClient client = HttpClient.newHttpClient();

        // 4. Build the POST request to the StructOCR Receipt endpoint
        HttpRequest request = HttpRequest.newBuilder()
                .uri(URI.create("https://api.structocr.com/v1/receipt"))
                .header("x-api-key", apiKey)
                .header("Content-Type", "application/json")
                .POST(HttpRequest.BodyPublishers.ofString(jsonPayload))
                .build();

        // 5. Execute request
        HttpResponse<String> response = client.send(request, HttpResponse.BodyHandlers.ofString());

        // 6. Parse the deeply structured JSON response
        Gson gson = new Gson();
        JsonObject jsonResponse = gson.fromJson(response.body(), JsonObject.class);

        // 7. Extract the financial data safely
        if (jsonResponse.has("success") && jsonResponse.get("success").getAsBoolean()) {
            JsonObject data = jsonResponse.getAsJsonObject("data");
            
            String merchant = data.getAsJsonObject("merchant").get("name").getAsString();
            String total = data.getAsJsonObject("financials").get("total_amount").getAsString();
            String currency = data.get("currency").getAsString();

            System.out.println("✅ Extracted Receipt Data");
            System.out.println("Merchant: " + merchant);
            System.out.println("Total Paid: " + total + " " + currency);

            // Loop through line items
            System.out.println("\n--- Line Items ---");
            JsonArray items = data.getAsJsonArray("line_items");
            for (JsonElement itemElement : items) {
                JsonObject item = itemElement.getAsJsonObject();
                String desc = item.get("description").getAsString();
                String amount = item.get("amount").getAsString();
                System.out.println("- " + desc + " : " + amount);
            }

        } else {
            String error = jsonResponse.has("error") && !jsonResponse.get("error").isJsonNull() 
                ? jsonResponse.get("error").getAsString() 
                : "Unknown extraction error.";
            System.out.println("❌ Failed: " + error);
        }
    }

    private static String encodeFileToBase64(String filePath) throws IOException {
        Path path = Path.of(filePath);
        byte[] fileContent = Files.readAllBytes(path);
        return Base64.getEncoder().encodeToString(fileContent);
    }
}