Java 支持JavaScript脚本计算

Java支持了JavaScript脚本的执行计算能力：

import javax.script.Invocable;
import javax.script.ScriptEngine;
import javax.script.ScriptEngineManager;
import javax.script.ScriptException;

public class JsExecutor {

private static ScriptEngine scriptEngine = new ScriptEngineManager().getEngineByName("js");

public static void main(String[] args) {
/*
*  采用js计算，思路就是将要计算的逻辑，拼接为一个js的函数，
*  然后通过scriptEngine执行这个函数，得到结果
*/
StringBuffer func = new StringBuffer();
func.append("function func() {");
func.append("    var a = 10;");
func.append("    return a>1;");
func.append("}");

try {
//编译js脚本
scriptEngine.eval(func.toString());

//计算编译后的js中的函数
Invocable inv = (Invocable) scriptEngine;
boolean result = (boolean) inv.invokeFunction("func");

System.out.println("result : " + result);
} catch (ScriptException e) {
System.out.println("error occurs in script");
} catch (NoSuchMethodException e) {
System.out.println("no such method in script");
}
}

}