不使用浏览器运行javascript代码的方法

import java.io.FileReader; 
import javax.script.ScriptEngine; 
import javax.script.ScriptEngineManager; 
public class RunScriptFile { 
public static void main(String[] args) { 
ScriptEngineManager manager = new ScriptEngineManager(); 
ScriptEngine engine = manager.getEngineByName("js"); 
try { 
FileReader reader = new FileReader("testFile.js"); 
engine.eval(reader); 
reader.close(); 
} catch (Exception e) { 
e.printStackTrace(); 
} 
} 
} 

function add(a, b) { 
c = a + b; 
return c; 
} 
result = add (10, 5); 
print ('Result = ' + result);