版本更新为Java WebStart

如何解决版本更新为Java WebStart

| 我正在将Java WebStart与正在使用的这个简单应用程序配合使用，并且我也做了此操作，以便它可以检查jar文件最新版本的更新。尽管在运行它时，我收到一条错误消息，指出服务器缺少版本响应。以下是我的jnlp文件代码：

<?xml version=\"1.0\" encoding=\"utf-8\"?> 
<jnlp spec=\"1.0+\" codebase=\"http://localhost:8081/WebStartLauncher/app\" href=\"Agecalc.jnlp\">
    <information>
    <title>Jnlp Testing</title>
    <vendor>Peter Ivan & co</vendor>
    <homepage href=\"http://localhost:8081/WebStartLauncher\" />
    <description>Testing Testing</description>
    <icon href=\"app/index.jpeg\" kind=\"default\"/>
    <icon kind=\"shortcut\" href=\"app/index.jpeg\" width=\"32\" height=\"32\"/>
    <offline-allowed/>
</information>
<security>
    <all-permissions/>
</security>
<resources>
    <j2se version=\"1.6+\" />
    <jar href=\"AgeCalc__V1.0.jar\" version=\"1.0\"/>
    <jar href=\"AgeCalc__V1.1.jar\" version=\"1.1\"/>
    <property name=\"jnlp.versionEnabled\" value=\"true\"/>
</resources>
<application-desc main-class=\"com.webstart.AgeCalculator\" />
</jnlp>

对于version.xml：

<jnlp-versions>
  <resource>
     <pattern>
       <name>AgeCalc__V1.0.jar</name>
        <version-id>1.0</version-id>
     </pattern>
     <file>AgeCalc__V1.0.jar</file>
  </resource>
</jnlp-versions>

对于web.xml：

<?xml version=\"1.0\" encoding=\"UTF-8\"?>
  <web-app id=\"WebApp_ID\" version=\"2.4\" xmlns=\"http://java.sun.com/xml/ns/j2ee\"xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\" xsi:schemaLocation=\"http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd\">
<display-name>WebStartLauncher</display-name>
<welcome-file-list>
    <welcome-file>webstart.jsp</welcome-file>
</welcome-file-list>
<servlet>
    <servlet-name>JnlpDownloadServlet</servlet-name>
    <servlet-class>jnlp.sample.servlet.JnlpDownloadServlet</servlet-class>
 </servlet>
 <servlet-mapping>
    <servlet-name>JnlpDownloadServlet</servlet-name>
    <url-pattern>/WebContent/WEB-INF/lib</url-pattern>
 </servlet-mapping>
</web-app>

这些是我得到的错误日志：

com.sun.deploy.net.FailedDownloadException: Unable to load resource: (http://localhost:8081/WebStartLauncher/app/AgeCalc__V1.0.jar,1.0)
at com.sun.deploy.net.DownloadEngine.actionDownload(UnkNown Source)
at com.sun.deploy.net.DownloadEngine.getCacheEntry(UnkNown Source)
at com.sun.deploy.net.DownloadEngine.getCacheEntry(UnkNown Source)
at com.sun.deploy.net.DownloadEngine.getResourceCacheEntry(UnkNown Source)
at com.sun.deploy.net.DownloadEngine.getResourceCacheEntry(UnkNown Source)
at com.sun.deploy.net.DownloadEngine.getResource(UnkNown Source)
at com.sun.javaws.launchdownload.downloadJarFiles(UnkNown Source)
at com.sun.javaws.launchdownload.downloadEagerorAll(UnkNown Source)
at com.sun.javaws.Launcher.downloadResources(UnkNown Source)
at com.sun.javaws.Launcher.preparelaunchFile(UnkNown Source)
at com.sun.javaws.Launcher.preparetoLaunch(UnkNown Source)
at com.sun.javaws.Launcher.launch(UnkNown Source)
at com.sun.javaws.Main.launchApp(UnkNown Source)
at com.sun.javaws.Main.continueInSecureThread(UnkNown Source)
at com.sun.javaws.Main$1.run(UnkNown Source)
at java.lang.Thread.run(UnkNown Source)


java.io.IOException: missing version response from server
at com.sun.deploy.net.DownloadEngine.actionDownload(UnkNown Source)
at com.sun.deploy.net.DownloadEngine.getCacheEntry(UnkNown Source)
at com.sun.deploy.net.DownloadEngine.getCacheEntry(UnkNown Source)
at com.sun.deploy.net.DownloadEngine.getResourceCacheEntry(UnkNown Source)
at com.sun.deploy.net.DownloadEngine.getResourceCacheEntry(UnkNown Source)
at com.sun.deploy.net.DownloadEngine.getResource(UnkNown Source)
at com.sun.javaws.launchdownload.downloadJarFiles(UnkNown Source)
at com.sun.javaws.launchdownload.downloadEagerorAll(UnkNown Source)
at com.sun.javaws.Launcher.downloadResources(UnkNown Source)
at com.sun.javaws.Launcher.preparelaunchFile(UnkNown Source)
at com.sun.javaws.Launcher.preparetoLaunch(UnkNown Source)
at com.sun.javaws.Launcher.launch(UnkNown Source)
at com.sun.javaws.Main.launchApp(UnkNown Source)
at com.sun.javaws.Main.continueInSecureThread(UnkNown Source)
at com.sun.javaws.Main$1.run(UnkNown Source)
at java.lang.Thread.run(UnkNown Source)

请告知如何进行。非常感谢！

解决方法

我认为，基于http://docs.oracle.com/javase/7/docs/technotes/guides/javaws/developersguide/downloadservletguide.html#requests，您正在混合两种可能的基于版本的下载策略。对于任何jar资源，您都可以使用文件名约定，在这种情况下不需要version.xml条目，并且jnlp条目将显示为

<jar href=\"AgeCalc.jar\" version=\"1.0\"/>

并且servlet将自动使用AgeCalc__V1.0.jar。另一种可能的方式是写

<resource>
   <pattern>
     <name>AgeCalc.jar</name>
     <version-id>1.0</version-id>
   </pattern>
   <file>AgeCalc__V1.0.jar</file>
</resource>

在您的version.xml中，结合上面更改过的jnlp。但是由于您使用的是文件名约定，所以我建议完全不要使用version.xml。当jnlp中的href包含__V时，DownloadServlet可能会出现问题。但是从Java 7开始，您甚至不再需要下载servlet。现在，客户可以做魔术。您所要做的就是将一个值为true的系统属性jnlp.versionEnabled添加到您的jnlp中。只要服务器上的文件采用* __ V $ {version} .jar格式，一切都将正常运行。但是您可以使用我的gradle插件，该插件将自动创建正确的Webstart目录，准备打包以进行部署。 , 您应该检查文件名。 AgeCalc__V1.0.jar和AgeCalc_V1.0.jar不同。重命名jar文件时，请确保在版本号之前包含两个下划线（__）。

<resources>
    <j2se version=\"1.6+\" />
    <jar href=\"AgeCalc.jar\" version=\"1.0\"/>
    <jar href=\"AgeCalc.jar\" version=\"1.1\"/>
    <property name=\"jnlp.versionEnabled\" value=\"true\"/>
</resources>

档案名称 AgeCalc__V1.0.jar和 AgeCalc__V1.1.jar