如何移除已弃用的ScriptObjectMirror并替换Nashorn API实现消息解码？

Got it, let's tackle this problem step by step. You're looking to ditch the Nashorn-specific ScriptObjectMirror (deprecated since JDK 11) and use standard JSR 223 scripting API features instead—here's exactly how to refactor your code to remove all Nashorn dependencies:

Key Concepts to Switch To #

Instead of relying on Nashorn's ScriptObjectMirror, we'll use standard Java collections (like Map<String, Object>) or custom POJOs to handle the JavaScript object returned by your decode function. This works because modern JS engines (like GraalVM JavaScript, the default in JDK 11+) automatically map plain JavaScript objects to Java Maps (or custom classes if you prefer type safety).

Refactored Code #

First, remove the Nashorn import entirely, then adjust the return type and logic:

import java.io.File;
import java.nio.file.Files;
import java.util.Map;
import javax.script.Invocable;
import javax.script.ScriptEngine;
import javax.script.ScriptEngineManager;
import org.springframework.core.io.ClassPathResource;

// Renamed method to follow Java camelCase conventions
public Map<String, Object> decodeString(String decodeString) {
    try {
        File resource = new ClassPathResource("script/decode.js").getFile();
        ScriptEngine engine = new ScriptEngineManager().getEngineByName("JavaScript");
        
        // Evaluate the script (uses standard API, no Nashorn ties)
        engine.eval(new String(Files.readAllBytes(resource.toPath())));
        Invocable inv = (Invocable) engine;
        
        // Call your helper function and decode payload
        byte[] bytes = (byte[]) inv.invokeFunction("hexToBytes", decodeString);
        // Cast directly to Map<String, Object> instead of ScriptObjectMirror
        Map<String, Object> data = (Map<String, Object>) inv.invokeFunction("DecodeElsysPayload", bytes);
        
        // Access values exactly like you did before
        System.out.println(data.entrySet().toString());
        System.out.println("temperature:" + data.get("temperature"));
        System.out.println("humidity:" + data.get("humidity"));
        
        return data;
    } catch (Exception e) {
        // Replace with specific exception handling (IOException, ScriptException, etc.) for production
        e.printStackTrace();
        throw new RuntimeException("Failed to decode payload", e);
    }
}

Optional: Type-Safe POJO Alternative #

If you want stronger type safety instead of using a Map, define a custom Java class that matches the structure of your decoded payload:

// Create a POJO to represent your decoded data
public class ElsysPayload {
    private double temperature;
    private double humidity;
    // Add other fields your script returns, plus getters/setters
    
    // Getters and Setters
    public double getTemperature() { return temperature; }
    public void setTemperature(double temperature) { this.temperature = temperature; }
    public double getHumidity() { return humidity; }
    public void setHumidity(double humidity) { this.humidity = humidity; }
}

Then update the method to cast directly to this class:

ElsysPayload data = (ElsysPayload) inv.invokeFunction("DecodeElsysPayload", bytes);
// Now you can use type-safe getters
System.out.println("temperature:" + data.getTemperature());

Important Notes #

• Engine Compatibility: This works with GraalVM JavaScript (default in JDK 11+) and any JSR 223-compliant JS engine—no extra dependencies needed.
• Script Requirements: Ensure your DecodeElsysPayload function returns a plain JavaScript object (not a Nashorn-specific object) for the auto-mapping to work.
• Exception Handling: Replace the generic Exception catch with specific exceptions (like IOException, ScriptException, NoSuchMethodException) for better error clarity in production.

内容的提问来源于stack exchange，提问作者JustAnotherNoob