当前位置: 首页>>技术问答>>正文


有没有办法更新所有Java相关的替代品?

ubuntuer 技术问答 , , 去评论

问题描述

有没有办法使用update-alternatives快速切换所有与Java相关的替代方案?

例如,如果要将Java切换到7,我运行sudo update-alternatives --config java并选择Java 7 OpenJdk。但如果我运行update-alternatives --get-selections | grep java,我会得到以下信息,

appletviewer                   auto     /usr/lib/jvm/java-6-openjdk-amd64/bin/appletviewer
extcheck                       auto     /usr/lib/jvm/java-6-openjdk-amd64/bin/extcheck
idlj                           auto     /usr/lib/jvm/java-6-openjdk-amd64/bin/idlj
itweb-settings                 auto     /usr/lib/jvm/java-6-openjdk-amd64/jre/bin/itweb-settings
jar                            auto     /usr/lib/jvm/java-6-openjdk-amd64/bin/jar
jarsigner                      auto     /usr/lib/jvm/java-6-openjdk-amd64/bin/jarsigner
java                           manual   /usr/lib/jvm/java-7-openjdk-amd64/jre/bin/java
javac                          auto     /usr/lib/jvm/java-6-openjdk-amd64/bin/javac
javadoc                        auto     /usr/lib/jvm/java-6-openjdk-amd64/bin/javadoc
javah                          auto     /usr/lib/jvm/java-6-openjdk-amd64/bin/javah
javap                          auto     /usr/lib/jvm/java-6-openjdk-amd64/bin/javap
javaws                         auto     /usr/lib/jvm/java-6-openjdk-amd64/jre/bin/javaws
jconsole                       auto     /usr/lib/jvm/java-6-openjdk-amd64/bin/jconsole
jdb                            auto     /usr/lib/jvm/java-6-openjdk-amd64/bin/jdb
jexec                          auto     /usr/lib/jvm/java-6-openjdk-amd64/jre/lib/jexec
jhat                           auto     /usr/lib/jvm/java-6-openjdk-amd64/bin/jhat
jinfo                          auto     /usr/lib/jvm/java-6-openjdk-amd64/bin/jinfo
jmap                           auto     /usr/lib/jvm/java-6-openjdk-amd64/bin/jmap
jps                            auto     /usr/lib/jvm/java-6-openjdk-amd64/bin/jps
jrunscript                     auto     /usr/lib/jvm/java-6-openjdk-amd64/bin/jrunscript
jsadebugd                      auto     /usr/lib/jvm/java-6-openjdk-amd64/bin/jsadebugd
jstack                         auto     /usr/lib/jvm/java-6-openjdk-amd64/bin/jstack
jstat                          auto     /usr/lib/jvm/java-6-openjdk-amd64/bin/jstat
jstatd                         auto     /usr/lib/jvm/java-6-openjdk-amd64/bin/jstatd
keytool                        auto     /usr/lib/jvm/java-6-openjdk-amd64/jre/bin/keytool
native2ascii                   auto     /usr/lib/jvm/java-6-openjdk-amd64/bin/native2ascii
orbd                           auto     /usr/lib/jvm/java-6-openjdk-amd64/jre/bin/orbd
pack200                        auto     /usr/lib/jvm/java-6-openjdk-amd64/jre/bin/pack200
policytool                     auto     /usr/lib/jvm/java-6-openjdk-amd64/jre/bin/policytool
rmic                           auto     /usr/lib/jvm/java-6-openjdk-amd64/bin/rmic
rmid                           auto     /usr/lib/jvm/java-6-openjdk-amd64/jre/bin/rmid
rmiregistry                    auto     /usr/lib/jvm/java-6-openjdk-amd64/jre/bin/rmiregistry
schemagen                      auto     /usr/lib/jvm/java-6-openjdk-amd64/bin/schemagen
serialver                      auto     /usr/lib/jvm/java-6-openjdk-amd64/bin/serialver
servertool                     auto     /usr/lib/jvm/java-6-openjdk-amd64/jre/bin/servertool
tnameserv                      auto     /usr/lib/jvm/java-6-openjdk-amd64/jre/bin/tnameserv
unpack200                      auto     /usr/lib/jvm/java-6-openjdk-amd64/jre/bin/unpack200
wsgen                          auto     /usr/lib/jvm/java-6-openjdk-amd64/bin/wsgen
wsimport                       auto     /usr/lib/jvm/java-6-openjdk-amd64/bin/wsimport
xjc                            auto     /usr/lib/jvm/java-6-openjdk-amd64/bin/xjc

正如您所看到的,我的Java替代方案已切换到7,但是基于OpenJDK 6的其他替代方案都没有切换。当然我可以手动切换每个人或写一个脚本来做到这一点,但我认为有一个更好的方法来实现这一目标。

最佳解决思路

诀窍是使用update-java-alternatives(来自java-common包)。

因此,为了获得OpenJDK 6到7,我使用update-java-alternatives -l获取Java备选列表,然后将sudo update-java-alternatives -s java-1.7.0-openjdk-amd64用于JDK。

注意:上面的命令引发了以下错误,

update-alternatives: error: no alternatives for mozilla-javaplugin.so.
update-java-alternatives: plugin alternative does not exist: /usr/lib/jvm/java-7-openjdk-amd64/jre/lib/amd64/IcedTeaPlugin.so

这是因为默认情况下未安装openjdk插件。修复运行

sudo apt-get install icedtea-7-plugin

并重新运行update-java-alternatives

次佳解决思路

jbro在http://ubuntuforums.org/showthread.php?t=1817528问了同样的问题,为这个问题写了一个脚本,

#!/bin/bash

update-alternatives --get-selections | grep -i openjdk |
while read line
do
    alternative=$(echo $line | awk '{print $1}')
    path=$(echo $line | awk '{print $3}')
    newpath=$(echo $path | sed -e 's/java-6-openjdk/java-6-sun/')
    status=unchanged
    if [ -f $newpath ]
    then
    status=modified
    echo "-> update-alternatives --set $alternative $newpath"
    update-alternatives --set $alternative $newpath
    else
    echo "$alternative unchanged"
    fi
done

如果没有更好的答案,这似乎是一个可靠的解决方法,但我认为update-alternatives必须有更好的方法来处理这个问题。

我编辑了一些代码,因为它不允许您在安装之前进行更改。我添加了两行如下……

#!/bin/bash

update-alternatives --get-selections | grep -i openjdk |
while read line
do
    alternative=$(echo $line | awk '{print $1}')
    path=$(echo $line | awk '{print $3}')
    newpath=$(echo $path | sed -e 's/java-6-openjdk/java-6-sun/')
    status=unchanged
    if [ -f $newpath ]
    then
    status=modified
echo "-> update-alternatives --install /usr/bin/$alternative $alternative $newpath 1"
update-alternatives --install /usr/bin/$alternative $alternative $newpath 1
    echo "-> update-alternatives --set $alternative $newpath"
    update-alternatives --set $alternative $newpath
    else
    echo "$alternative unchanged"
    fi
done

参考资料

本文由Ubuntu问答整理, 博文地址: https://ubuntuqa.com/article/1732.html,未经允许,请勿转载。