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

因为JS是动态语言，不需要编译，因此可以通过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;
@SpringBootApplicationpublic class DemoApplication {
   public static void main(String[] args) {      SpringApplication.run(DemoApplication.class, args);   }}

代码仓库

• 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    }}

四、引用

• https://www.graalvm.org/reference-manual/js/JavaInteroperability/

• https://github.com/graalvm/graaljs/blob/master/docs/user/JavaScriptCompatibility.md

• http://www.liuhaihua.cn/archives/710296.html