Java中如何使用JavaScript脚本

function scriptFunction(obj){
 var a = 1;
 var b = 2;
 return obj.sum(a,b);
}
scriptFunction(obj);//调用该方法

public class ScirptContainer {
 
 
 public static ScriptEngine engine;//脚本引擎
 
 static {
 ScriptEngineManager manager = new ScriptEngineManager();//脚本引擎管理
 engine = manager.getEngineByName("nashorn");//获取nashorn脚本引擎
 engine.getContext().getWriter();//获取正文并且写入
 }
 
 private ConcurrentHashMap<Integer, CompiledScript> scripts = new ConcurrentHashMap<>();//脚本存储容器
 
 
 public CompiledScript getCompiledScript(String script) throws ScriptException{
 //判断脚本是否为空
 if(script == null || "".equals(script)){
 throw new ScriptException("JavaScript empty");
 }
 //获取脚本Hash
 int hashCode = script.hashCode();
 //从容器中获取脚本
 CompiledScript compiledScript = scripts.get(hashCode);
 if(compiledScript == null){
 //容器中无脚本创建脚本对象
 Compilable compilable = (Compilable) engine;
 //编译JavaScript脚本
 compiledScript = compilable.compile(script);
 //脚本对象存入容器中
 scripts.put(hashCode, compiledScript);
 }
 return compiledScript;
 } 
}

public class ScriptHandler {
 
 //创建容器对象
 private ScirptContainer scirptContainer = new ScirptContainer();
 
 //需要执行的对象
 String js1 = "function scriptFunction(obj){ var a = 1; var b = 2; return obj.sum(a,b); } scriptFunction(obj);";
 
 @Test
 public void test() throws ScriptException{
 //获取脚本对象
 CompiledScript c1 = scirptContainer.getCompiledScript(js1);
 //创建参数绑定
 Bindings bindings = scirptContainer.engine.createBindings();
 //obj参数绑定SumTest类
 bindings.put("obj", new SumTest());
 //执行JavaScript脚本并且打印返回值
 System.out.println(c1.eval(bindings));
 }
}