原创

Spring Boot 集成GraalVM js引擎快速入门demo

一、GraalVM.js介绍

是一款 JavaScript 解释器/编译器，能够在 JVM 上运行 Node.js 应用；

主要应用场景

通过JS动态改变程序执行逻辑，比如：风控规则，服务编排等等

二、代码工程

pom.xml

<?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">
    <parent>
        <artifactId>springboot-demo</artifactId>
        <groupId>com.et</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>graalvm-js</artifactId>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
    </properties>
    <dependencies>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-autoconfigure</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>org.graalvm.js</groupId>
            <artifactId>js-scriptengine</artifactId>
            <version>20.2.0</version>
        </dependency>
        <dependency>
            <groupId>org.graalvm.js</groupId>
            <artifactId>js</artifactId>
            <version>20.2.0</version>
        </dependency>

    </dependencies>

</project>

属性文件

server:
  port: 8088

启动类

package com.et.graalvm.js;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class DemoApplication {

   public static void main(String[] args) {
      SpringApplication.run(DemoApplication.class, args);
   }
}

https://github.com/Harries/springboot-demo

三、测试

本地调用

package com.et.graalvm.js;

import org.junit.Test;

import javax.script.*;

/**
 * @author liuhaihua
 * @version 1.0
 * @ClassName com.et.graalvm.js.JSTest
 * @Description todo
 * @date 2024年03月07日 9:47
 */

public class JSTest {
    @Test
    public  void test10(){
        // 创建JavaScript引擎
        ScriptEngine jsEngine = new ScriptEngineManager().getEngineByName("js");
//        ScriptEngine jsEngine = new ScriptEngineManager().getEngineByExtension("js");
//        ScriptEngine jsEngine = new ScriptEngineManager().getEngineByMimeType("text/javascript");
        // 方式一，默认设置变量
        jsEngine.put("hello", "jack");
        // 方式二，使用binding设置变量
        SimpleBindings bindings = new SimpleBindings();
        bindings.put("hello","world");
        jsEngine.setBindings(bindings, ScriptContext.GLOBAL_SCOPE);
        // 方式三，使用Context设置变量
        ScriptContext scriptContext = jsEngine.getContext();
        scriptContext.setAttribute("hello", "polo", ScriptContext.ENGINE_SCOPE);
        try {
            // 方式一，直接调用
            jsEngine.eval("print(hello)");
            // 方式二，编译调用(需要重复调用，建议先编译后调用)
            if (jsEngine instanceof Compilable){
                CompiledScript compileScript = ((Compilable) jsEngine).compile("print(hello)");
                if (compileScript != null){
                    for (int i = 0; i < 10; i++) {
                        compileScript.eval();
                    }
                }
            }
            Invocable invocable = ((Invocable)jsEngine);
            // 方式三，使用JavaScript中的顶层方法
            jsEngine.eval("function greet(name) { print('Hello, ' + name); } ");
            invocable.invokeFunction("greet", "tom");
            // 方式四，使用某个对象的方法
            jsEngine.eval("var obj = { getGreeting: function(name){ return 'hello, ' + name; } } ");
            Object obj = jsEngine.get("obj");
            Object result = invocable.invokeMethod(obj, "getGreeting", "kitty");
            System.out.println(result);

        } catch (ScriptException | NoSuchMethodException e) {
            e.printStackTrace();
        }
    }
}

远程调用

package com.et.graalvm.js;

import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.BufferedReader;
import java.io.IOException;
import java.net.URL;
import java.net.URLConnection;
import javax.script.ScriptEngine;
import javax.script.ScriptEngineManager;
import javax.script.ScriptException;

public class RemoteJSTest {
    public static void main(String[] args) throws IOException, ScriptException {
        URL jsUrl = new URL("https://example.com/script.js"); // js文件的URL
        URLConnection connection = jsUrl.openConnection();
        InputStream inputStream = connection.getInputStream(); // 获取js文件的流

        BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));
        StringBuilder sb = new StringBuilder();
        String line;
        while ((line = reader.readLine()) != null) {
            sb.append(line).append("\n"); // 将js文件的内容存入StringBuilder
        }
        reader.close();
        inputStream.close();

        ScriptEngineManager engineManager = new ScriptEngineManager();
        ScriptEngine engine = engineManager.getEngineByName("nashorn"); // 获取Nashorn引擎
        String script = sb.toString(); // js文件的内容
        engine.eval(script); // 运行js文件

        Object result = engine.eval("hello()"); // 调用js文件中名为"hello"的函数
        System.out.println(result); // 输出结果
    }
}