使用OpenAPI/Swagger模式直接验证JSON输入：实践指南

<!-- Maven 示例 -->
<dependency>
    <groupId>org.openapi4j</groupId>
    <artifactId>openapi-parser</artifactId>
    <version>2.0.0</version> <!-- 请使用最新稳定版本 -->
</dependency>
<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-databind</artifactId>
    <version>2.15.2</version> <!-- 确保与你的项目兼容 -->
</dependency>

import org.openapi4j.core.model.v3.OpenApi3;
import org.openapi4j.parser.OpenApi3Parser;
import org.openapi4j.parser.model.v3.Schema;
import org.openapi4j.parser.validation.v3.ValidationApi;
import org.openapi4j.core.validation.ValidationResults;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;

import java.io.File;
import java.io.IOException;
import java.net.URL;

public class JsonSchemaValidator {

    public static void main(String[] args) {
        try {
            // 假设你的OpenAPI定义文件在resources目录下或可通过URL访问
            // File openApiFile = new File("src/main/resources/openapi.yaml");
            URL openApiUrl = new URL("file:///path/to/your/openapi.yaml"); // 或 http://your-api.com/openapi.json

            // 1. 解析OpenAPI规范
            OpenApi3Parser parser = new OpenApi3Parser();
            OpenApi3 api = parser.parse(openApiUrl);

            // 检查解析过程中是否有错误
            if (api == null) {
                System.err.println("Failed to parse OpenAPI document.");
                return;
            }

            // 假设我们要验证的JSON数据对应于OpenAPI定义中名为"MyRequestBody"的Schema
            // 这个Schema通常定义在 components/schemas 下
            Schema targetSchema = api.getComponents().getSchemas().get("MyRequestBody");

            if (targetSchema == null) {
                System.err.println("Target schema 'MyRequestBody' not found in OpenAPI document.");
                return;
            }

            // 2. 准备待验证的JSON数据
            String validJsonInput = "{\"name\": \"Alice\", \"age\": 30, \"email\": \"alice@example.com\"}";
            String invalidJsonInput = "{\"name\": \"Bob\", \"age\": \"twenty\", \"email\": \"invalid-email\"}"; // age类型错误, email格式错误

            ObjectMapper mapper = new ObjectMapper();
            JsonNode validJsonNode = mapper.readTree(validJsonInput);
            JsonNode invalidJsonNode = mapper.readTree(invalidJsonInput);

            // 3. 执行验证
            System.out.println("--- 验证有效JSON ---");
            ValidationResults validResults = new ValidationApi(api).validate(validJsonNode, targetSchema);
            if (validResults.has  Errors()) {
                System.out.println("有效JSON验证失败:");
                validResults.getErrors().forEach(System.out::println);
            } else {
                System.out.println("有效JSON验证成功！");
            }

            System.out.println("\n--- 验证无效JSON ---");
            ValidationResults invalidResults = new ValidationApi(api).validate(invalidJsonNode, targetSchema);
            if (invalidResults.has  Errors()) {
                System.out.println("无效JSON验证失败，错误详情:");
                invalidResults.getErrors().forEach(System.out::println);
            } else {
                System.out.println("无效JSON验证成功 (这不应该发生)！");
            }

        } catch (IOException e) {
            System.err.println("Error reading OpenAPI file or JSON input: " + e.getMessage());
        } catch (Exception e) {
            System.err.println("An unexpected error occurred: " + e.getMessage());
            e.printStackTrace();
        }
    }
}

openapi: 3.0.0
info:
  title: Sample API
  version: 1.0.0
paths: {}
components:
  schemas:
    MyRequestBody:
      type: object
      required:
        - name
        - age
        - email
      properties:
        name:
          type: string
          description: User's full name
        age:
          type: integer
          format: int32
          minimum: 0
          description: User's age
        email:
          type: string
          format: email
          description: User's email address