在Neo4j中运行TypeSafe AI的Jev：实现置信度感知的情感判断

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.example</groupId>
    <artifactId>jev-neo4j-poc</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>jar</packaging>

    <properties>
        <maven.compiler.source>21</maven.compiler.source>
        <maven.compiler.target>21</maven.compiler.target>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <neo4j.version>2026.07.0</neo4j.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.neo4j</groupId>
            <artifactId>neo4j</artifactId>
            <version>${neo4j.version}</version>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>2.17.2</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <source>21</source>
                    <target>21</target>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-shade-plugin</artifactId>
                <version>3.5.1</version>
                <executions>
                    <execution>
                        <phase>package</phase>
                        <goals>
                            <goal>shade</goal>
                        </goals>
                        <configuration>
                            <artifactSet>
                                <excludes>
                                    <exclude>org.neo4j:*</exclude>
                                </excludes>
                            </artifactSet>
                            <relocations>
                                <relocation>
                                    <pattern>com.fasterxml.jackson</pattern>
                                    <shadedPattern>com.example.jev.shaded.jackson</shadedPattern>
                                </relocation>
                            </relocations>
                        </configuration>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>
</project>

package com.example;

import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.node.ArrayNode;
import com.fasterxml.jackson.databind.node.ObjectNode;
import org.neo4j.procedure.Description;
import org.neo4j.procedure.Name;
import org.neo4j.procedure.UserFunction;

import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
import java.util.HashMap;
import java.util.Map;

public class JevUDF {

    private static final String API_URL = "https://api.typesafe.ai/v1/systemone";
    private static final ObjectMapper mapper = new ObjectMapper();
    private static final HttpClient client = HttpClient.newHttpClient();

    private static String getApiKey() {
        String key = System.getenv("TYPESAFE_API_KEY");
        if (key == null || key.isBlank()) {
            key = System.getProperty("TYPESAFE_API_KEY");
        }
        if (key == null || key.isBlank()) {
            throw new RuntimeException("TYPESAFE_API_KEY not set as environment variable or JVM property");
        }
        return key;
    }

    @UserFunction("com.example.jev.sentiment")
    @Description("Classifies text sentiment using Jev (TypeSafe AI). Returns choice, probabilities and confidence.")
    public Map<String, Object> sentiment(@Name("text") String text) throws Exception {

        if (text == null || text.isBlank()) {
            Map<String, Object> empty = new HashMap<>();
            empty.put("choice", "neutral");
            empty.put("confidence", 0.0);
            return empty;
        }

        String apiKey = getApiKey();

        ObjectNode body = mapper.createObjectNode();
        body.put("model", "jev-latest");
        body.put("state", text);

        ObjectNode questions = mapper.createObjectNode();

        ObjectNode sentiment = mapper.createObjectNode();
        sentiment.put("type", "choice");
        sentiment.put("instructions", "What is the overall sentiment of this text?");
        ObjectNode criteria = mapper.createObjectNode();
        criteria.put("positive", "Text expresses positive sentiment");
        criteria.put("negative", "Text expresses negative sentiment");
        criteria.put("neutral", "Text is neutral or factual");
        sentiment.set("criteria", criteria);
        questions.set("sentiment", sentiment);

        ObjectNode confidence = mapper.createObjectNode();
        confidence.put("type", "score");
        confidence.put("instructions", "How confident are you in the sentiment classification?");
        ArrayNode levels = mapper.createArrayNode();
        levels.add("Not confident");
        levels.add("Somewhat confident");
        levels.add("Very confident");
        confidence.set("criteria", levels);
        questions.set("confidence", confidence);

        body.set("questions", questions);

        HttpRequest request = HttpRequest.newBuilder()
                .uri(URI.create(API_URL))
                .header("Content-Type", "application/json")
                .header("Authorization", "Bearer " + apiKey)
                .POST(HttpRequest.BodyPublishers.ofString(mapper.writeValueAsString(body)))
                .build();

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

        if (response.statusCode() != 200) {
            throw new RuntimeException("Jev API error " + response.statusCode() + ": " + response.body());
        }

        JsonNode result = mapper.readTree(response.body());
        JsonNode answers = result.get("answers");
        JsonNode sentimentAnswer = answers.get("sentiment");
        JsonNode confidenceAnswer = answers.get("confidence");

        Map<String, Object> output = new HashMap<>();
        output.put("choice", sentimentAnswer.get("choice").asText());
        output.put("confidence", sentimentAnswer.get("confidence").asDouble());
        output.put("score", confidenceAnswer.get("score").asDouble());
        output.put("positive", sentimentAnswer.get("probabilities").get("positive").asDouble());
        output.put("negative", sentimentAnswer.get("probabilities").get("negative").asDouble());
        output.put("neutral", sentimentAnswer.get("probabilities").get("neutral").asDouble());

        return output;
    }
}