从Rhino切换到Nashorn [英] Switching from Rhino to Nashorn

问题描述

我有一个Java 7项目，该项目大量使用Javascript来编写各种功能的脚本。到现在为止，我使用Rhino作为脚本引擎。我现在想转向Java 8，这也意味着我将取代Nashorn的Rhino。

I have a Java 7 project which makes a lot of use of Javascript for scripting various features. Until now I was using Rhino as script engine. I would now like to move to Java 8, which also means that I will replace Rhino by Nashorn.

Nashorn与Rhino的兼容性如何？我可以将它用作替代品，还是我可以预期我的一些脚本将不再工作并且需要移植到新引擎？ Nashorn不支持任何常用的Rhino功能吗？

How compatible is Nashorn to Rhino? Can I use it as a drop-in replacement, or can I expect that some of my scripts will not work anymore and will need to be ported to the new engine? Are there any commonly-used features of Rhino which are not supported by Nashorn?

推荐答案

一个问题是Nashorn不能再通过使用 importPackage（com.organization.project.package）;

One problem is that Nashorn can no longer by default import whole Java packages into the global scope by using importPackage(com.organization.project.package);

默认将整个Java包导入全局范围但是，有一个简单的解决方法：通过在脚本中添加此行，您可以启用Rhino的旧行为：

There is, however, a simple workaround: By adding this line to your script, you can enable the old behavior of Rhino:

load("nashorn:mozilla_compat.js");

我遇到的另一个问题是，在java和javascript之间传递数据时，某些类型转换的工作方式不同。例如，将Javascript数组传递给Java时到达的对象不能再转换为 List ，但可以将其强制转换为 Map< ; String，Object> 。作为一种解决方法，您可以使用 Java.to（array，Java.type（java.util.List））将Javascript数组转换为Javascript代码中的Java List。

Another problem I ran into is that certain type-conversions when passing data between java and javascript work differently. For example, the object which arrives when you pass a Javascript array to Java can no longer be cast to List, but it can be cast to a Map<String, Object>. As a workaround you can convert the Javascript array to a Java List in the Javascript code using Java.to(array, Java.type("java.util.List"))

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