<p style="font-family:Verdana, Geneva, Arial, Helvetica, sans-serif;margin-top:10px;margin-bottom:10px;padding:0px;"><strong style="line-height:normal;"> 6、Rhino如何调用js文件</strong></p> <p style="font-family:Verdana, Geneva, Arial, Helvetica, sans-serif;margin-top:10px;margin-bottom:10px;padding:0px;"> 当然,除了在命令行的方式,我们还可以使用操纵JavaScript文件。下面是一段JavaScript代码,主要目的是判断该数是否为质数。代码如下:</p> <p style="font-family:Verdana, Geneva, Arial, Helvetica, sans-serif;margin-top:10px;margin-bottom:10px;padding:0px;"></p> <div style="font-family:Verdana, Geneva, Arial, Helvetica, sans-serif;color:rgb(51,51,51);background-color:rgb(221,221,221);border-style:solid;width:612px;"> <tbody> <tr> <td> <ol> <li><span>function isPrime (num) </span></li> <li><span>{ </span></li> <li> <span>if (num </span><span><strong><</strong></span><span>= 1) { </span> </li> <li><span>print("Enter an integer no less than 2.") </span></li> <li><span>return false </span></li> <li><span>} </span></li> <li> <span>var </span><span>prime</span><span> = </span><span>true</span> </li> <li> <span>var </span><span>sqrRoot</span><span> = </span><span>Math</span><span>.round(Math.sqrt(num)) </span> </li> <li> <span>for (var </span><span>n</span><span> = </span><span>2</span><span>; prime & n </span><span><strong><</strong></span><span>= sqrRoot; ++n) { </span> </li> <li> <span>prime</span><span> = (num % n != 0) </span> </li> <li><span>} </span></li> <li><span>return prime </span></li> <li><span>}</span></li> </ol> </td> </tr> </tbody> </div> <p style="font-family:Verdana, Geneva, Arial, Helvetica, sans-serif;margin-top:10px;margin-bottom:10px;padding:0px;"></p> <p style="font-family:Verdana, Geneva, Arial, Helvetica, sans-serif;margin-top:10px;margin-bottom:10px;padding:0px;"> 我们保存文件为C:isPrime.js。然后我们需要调用load方法加载该脚本。最后,我们可以调用isPrime方法来判断是否为质数。</p> <p style="font-family:Verdana, Geneva, Arial, Helvetica, sans-serif;margin-top:10px;margin-bottom:10px;padding:0px;"></p> <div style="font-family:Verdana, Geneva, Arial, Helvetica, sans-serif;color:rgb(51,51,51);background-color:rgb(221,221,221);border-style:solid;width:612px;"> <tbody> <tr> <td> <ol> <li><span><span>js</span><span><strong>></strong></span><span> load("C:/isPrime.js") </span></span></li> <li> <span>js</span><span><strong>></strong></span><span> isPrime(33); </span> </li> <li><span>false </span></li> <li> <span>js</span><span><strong>></strong></span><span> isPrime(31) </span> </li> <li><span>true</span></li> </ol> </td> </tr> </tbody> </div> <p style="font-family:Verdana, Geneva, Arial, Helvetica, sans-serif;margin-top:10px;margin-bottom:10px;padding:0px;"></p> <p style="font-family:Verdana, Geneva, Arial, Helvetica, sans-serif;margin-top:10px;margin-bottom:10px;padding:0px;"> 需要注意的是,注意:文件分隔符需要调整,是“/”而不是“”。</p> <p style="font-family:Verdana, Geneva, Arial, Helvetica, sans-serif;margin-top:10px;margin-bottom:10px;padding:0px;"> 上述部分示例可以参见Rhino官方网站。另外examples目录下很多例子都值得参考与学习。</p> <p style="font-family:Verdana, Geneva, Arial, Helvetica, sans-serif;margin-top:10px;margin-bottom:10px;padding:0px;"> 刚才使用JavaScript操纵Java对象。接下来我们看看如何使用Java程序访问JavaScript</p> <p style="font-family:Verdana, Geneva, Arial, Helvetica, sans-serif;margin-top:10px;margin-bottom:10px;padding:0px;"> Java对象操纵JavaScript</p> <p style="font-family:Verdana, Geneva, Arial, Helvetica, sans-serif;margin-top:10px;margin-bottom:10px;padding:0px;"> 下面是一段Java代码,用来运行数学表达式。代码如下:</p> <p style="font-family:Verdana, Geneva, Arial, Helvetica, sans-serif;margin-top:10px;margin-bottom:10px;padding:0px;"></p> <div style="font-family:Verdana, Geneva, Arial, Helvetica, sans-serif;color:rgb(51,51,51);background-color:rgb(221,221,221);border-style:solid;width:612px;"> <tbody> <tr> <td> <ol> <li><span>package com.example; </span></li> <li><span>import sun.org.mozilla.javascript.internal.Context; </span></li> <li><span>import sun.org.mozilla.javascript.internal.Scriptable; </span></li> <li><span>publicclass Test { </span></li> <li><span>publicstaticvoid main(String[] args) { </span></li> <li> <span>Context </span><span>cx</span><span> = </span><span>Context</span><span>.enter(); </span> </li> <li><span>try { </span></li> <li> <span>Scriptable </span><span>scope</span><span> = </span><span>cx</span><span>.initStandardObjects(); </span> </li> <li> <span>String </span><span>str</span><span> = </span><span>"3/(1+2)"</span><span>; </span> </li> <li> <span>Object </span><span>result</span><span> = </span><span>cx</span><span>.evaluateString(scope, str, null, 1, null); </span> </li> <li><span>System.out.println(str + "=" + Context.toNumber(result)); </span></li> <li><span>} finally { </span></li> <li><span>Context.exit(); </span></li> <li><span>} </span></li> <li><span>} </span></li> <li><span>}</span></li> </ol> </td> </tr> </tbody> </div> <p style="font-family:Verdana, Geneva, Arial, Helvetica, sans-serif;margin-top:10px;margin-bottom:10px;padding:0px;"></p> <p style="font-family:Verdana, Geneva, Arial, Helvetica, sans-serif;margin-top:10px;margin-bottom:10px;padding:0px;"> 运行Java com.example.Test,输出结果如下:</p> <p style="font-family:Verdana, Geneva, Arial, Helvetica, sans-serif;margin-top:10px;margin-bottom:10px;padding:0px;"> 3/(1+2)=1.0</p> <p style="font-family:Verdana, Geneva, Arial, Helvetica, sans-serif;margin-top:10px;margin-bottom:10px;padding:0px;"> 之所以是1.0而不是1,是因为Context.toNumber(result)返回的类型为double。另一个值得注意的是,这里import的package属于JDK 6.0。因此,在不需要Rhino提供的js.jar,该程序仍能独立运行。</p> <p style="font-family:Verdana, Geneva, Arial, Helvetica, sans-serif;margin-top:10px;margin-bottom:10px;padding:0px;"> 虽然Rhino作为JavaScript运行时,功能非常强大,但在性能上却无法与其他的JavaScript运行时(比如Google Chrome的V8 JavaScript Engine)相提并论。值得注意的是,JRuby专家Charles Oliver Nutter也开始参与Rhino项目中,以提升Rhino JavaScript运行时的速度,进而实现与V8的竞争。而Oracle在对JVM上的JavaScript改进与优化,我们有理由期待,在未来,新一代JavaScript运行时Nashorn的速度将会得到极大的提升。</p> <p style="font-family:Verdana, Geneva, Arial, Helvetica, sans-serif;margin-top:10px;margin-bottom:10px;padding:0px;"><br></p> <p style="margin-top:10px;margin-bottom:10px;padding:0px;"><font>本文出自seven的测试人生公众号最新内容请见作者的GitHub页:http://qaseven.github.io/</font><br></p>
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