idea fetching documentation解决

使用idea的某天突然发现鼠标放在方法名上时无法获取到javadoc，悬浮框里一致显示fetching documentation… 最后发现了原因是javadoc的获取来源指定了oracle的地址，可以通过以下方法解决：
首先找到 用户目录.IntelliJIdea2016.2\config\options\jdk.table.xml 这个文件打开

<application>
  <component name="ProjectJdkTable">
    <jdk version="2">
      <name value="1.8" />
      <type value="JavaSDK" />
      <version value="java version &quot;1.8.0_20&quot;" />
      <homePath value="D:/zhao/jdk" />
      <roots>
        <annotationsPath>
          <root type="composite">
            <root type="simple" url="jar://$APPLICATION_HOME_DIR$/lib/jdkAnnotations.jar!/" />
          </root>
        </annotationsPath>
        <classPath>
          <root type="composite">
            <root type="simple" url="jar://D:/zhao/jdk/jre/lib/charsets.jar!/" />
            <root type="simple" url="jar://D:/zhao/jdk/jre/lib/deploy.jar!/" />
            <root type="simple" url="jar://D:/zhao/jdk/jre/lib/ext/access-bridge-64.jar!/" />
            <root type="simple" url="jar://D:/zhao/jdk/jre/lib/ext/cldrdata.jar!/" />
            <root type="simple" url="jar://D:/zhao/jdk/jre/lib/ext/dnsns.jar!/" />
            <root type="simple" url="jar://D:/zhao/jdk/jre/lib/ext/jaccess.jar!/" />
            <root type="simple" url="jar://D:/zhao/jdk/jre/lib/ext/jfxrt.jar!/" />
            <root type="simple" url="jar://D:/zhao/jdk/jre/lib/ext/localedata.jar!/" />
            <root type="simple" url="jar://D:/zhao/jdk/jre/lib/ext/nashorn.jar!/" />
            <root type="simple" url="jar://D:/zhao/jdk/jre/lib/ext/sunec.jar!/" />
            <root type="simple" url="jar://D:/zhao/jdk/jre/lib/ext/sunjce_provider.jar!/" />
            <root type="simple" url="jar://D:/zhao/jdk/jre/lib/ext/sunmscapi.jar!/" />
            <root type="simple" url="jar://D:/zhao/jdk/jre/lib/ext/sunpkcs11.jar!/" />
            <root type="simple" url="jar://D:/zhao/jdk/jre/lib/ext/zipfs.jar!/" />
            <root type="simple" url="jar://D:/zhao/jdk/jre/lib/javaws.jar!/" />
            <root type="simple" url="jar://D:/zhao/jdk/jre/lib/jce.jar!/" />
            <root type="simple" url="jar://D:/zhao/jdk/jre/lib/jfr.jar!/" />
            <root type="simple" url="jar://D:/zhao/jdk/jre/lib/jfxswt.jar!/" />
            <root type="simple" url="jar://D:/zhao/jdk/jre/lib/jsse.jar!/" />
            <root type="simple" url="jar://D:/zhao/jdk/jre/lib/management-agent.jar!/" />
            <root type="simple" url="jar://D:/zhao/jdk/jre/lib/plugin.jar!/" />
            <root type="simple" url="jar://D:/zhao/jdk/jre/lib/resources.jar!/" />
            <root type="simple" url="jar://D:/zhao/jdk/jre/lib/rt.jar!/" />
          </root>
        </classPath>
        <javadocPath>
          <root type="composite" />
        </javadocPath>
        <sourcePath>
          <root type="composite">
            <root type="simple" url="jar://D:/zhao/jdk/src.zip!/" />
            <root type="simple" url="jar://D:/zhao/jdk/javafx-src.zip!/" />
          </root>
        </sourcePath>
      </roots>
      <additional />
    </jdk>
    <jdk version="2">
      <name value="1.7" />
      <type value="JavaSDK" />
      <version value="java version &quot;1.7.0_45&quot;" />
      <homePath value="D:/zhao/java/jdk1.7.0_45" />
      <roots>
        <annotationsPath>
          <root type="composite">
            <root type="simple" url="jar://$APPLICATION_HOME_DIR$/lib/jdkAnnotations.jar!/" />
          </root>
        </annotationsPath>
        <classPath>
          <root type="composite">
            <root type="simple" url="jar://D:/zhao/java/jdk1.7.0_45/jre/lib/charsets.jar!/" />
            <root type="simple" url="jar://D:/zhao/java/jdk1.7.0_45/jre/lib/deploy.jar!/" />
            <root type="simple" url="jar://D:/zhao/java/jdk1.7.0_45/jre/lib/ext/access-bridge.jar!/" />
            <root type="simple" url="jar://D:/zhao/java/jdk1.7.0_45/jre/lib/ext/dnsns.jar!/" />
            <root type="simple" url="jar://D:/zhao/java/jdk1.7.0_45/jre/lib/ext/jaccess.jar!/" />
            <root type="simple" url="jar://D:/zhao/java/jdk1.7.0_45/jre/lib/ext/localedata.jar!/" />
            <root type="simple" url="jar://D:/zhao/java/jdk1.7.0_45/jre/lib/ext/sunec.jar!/" />
            <root type="simple" url="jar://D:/zhao/java/jdk1.7.0_45/jre/lib/ext/sunjce_provider.jar!/" />
            <root type="simple" url="jar://D:/zhao/java/jdk1.7.0_45/jre/lib/ext/sunmscapi.jar!/" />
            <root type="simple" url="jar://D:/zhao/java/jdk1.7.0_45/jre/lib/ext/sunpkcs11.jar!/" />
            <root type="simple" url="jar://D:/zhao/java/jdk1.7.0_45/jre/lib/ext/zipfs.jar!/" />
            <root type="simple" url="jar://D:/zhao/java/jdk1.7.0_45/jre/lib/javaws.jar!/" />
            <root type="simple" url="jar://D:/zhao/java/jdk1.7.0_45/jre/lib/jce.jar!/" />
            <root type="simple" url="jar://D:/zhao/java/jdk1.7.0_45/jre/lib/jfr.jar!/" />
            <root type="simple" url="jar://D:/zhao/java/jdk1.7.0_45/jre/lib/jfxrt.jar!/" />
            <root type="simple" url="jar://D:/zhao/java/jdk1.7.0_45/jre/lib/jsse.jar!/" />
            <root type="simple" url="jar://D:/zhao/java/jdk1.7.0_45/jre/lib/management-agent.jar!/" />
            <root type="simple" url="jar://D:/zhao/java/jdk1.7.0_45/jre/lib/plugin.jar!/" />
            <root type="simple" url="jar://D:/zhao/java/jdk1.7.0_45/jre/lib/resources.jar!/" />
            <root type="simple" url="jar://D:/zhao/java/jdk1.7.0_45/jre/lib/rt.jar!/" />
          </root>
        </classPath>
        <javadocPath>
          <root type="composite">
            <root type="simple" url="http://docs.oracle.com/javafx/2/api/" />
          </root>
        </javadocPath>
        <sourcePath>
          <root type="composite">
            <root type="simple" url="jar://D:/zhao/java/jdk1.7.0_45/src.zip!/" />
          </root>
        </sourcePath>
      </roots>
      <additional />
    </jdk>
  </component>
</application>

这里我的环境装了2个jdk，仔细看可以发现1.7的版本下比1.8多了一行配置

<javadocPath>
          <root type="composite">
            <root type="simple" url="http://docs.oracle.com/javafx/2/api/" />
          </root>
        </javadocPath>

这个时候在使用1.7的jdk的情况下，如果你的网络有限制连不上oracle的网站，就会出现一直fetching documentation 的情况，我们只需要将 url所在的那一行删掉就能正常读取到本地的javadoc了。