我一直在检查所有相关问题，但解决方案并没有解决我遇到的问题。
我正在尝试设置EC2实例，安装php7.0，mysql，composer，克隆存储库等。
此EC2实例是Centos 6.5。
但是：
php bin/console cache:clear --env=prod --no-debug
我得到了：
PHP Fatal error: Uncaught Error: Class 'DOMDocument' not found in /var/www/html/TFM_RedSocialMusical/vendor/symfony/symfony/src/Symfony/Component/Config/Util/XmlUtils.php:52
Stack trace:
#0 /var/www/html/TFM_RedSocialMusical/vendor/symfony/symfony/src/Symfony/Component/DependencyInjection/Loader/XmlFileLoader.php(263): Symfony\Component\Config\Util\XmlUtils::loadFile('/var/www/html/T...', Array)
#1 /var/www/html/TFM_RedSocialMusical/vendor/symfony/symfony/src/Symfony/Component/DependencyInjection/Loader/XmlFileLoader.php(41): Symfony\Component\DependencyInjection\Loader\XmlFileLoader->parseFileToDOM('/var/www/html/T...')
#2 /var/www/html/TFM_RedSocialMusical/vendor/symfony/symfony/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/FrameworkExtension.php(72): Symfony\Component\DependencyInjection\Loader\XmlFileLoader->load('web.xml')
#3 /var/www/html/TFM_RedSocialMusical/vendor/symfony/symfony/src/Symfony/Component/DependencyInjection/Compiler/MergeExtensionConfigurationPass.php(59): Symfony\Bundle\FrameworkBundle\Dependen in /var/www/html/TFM_RedSocialMusical/vendor/symfony/symfony/src/Symfony/Component/Config/Util/XmlUtils.php on line 52
嗯，搜索类似的问题，目的是解决方案：
sudo yum install php-xml
我得到了：
Loaded plugins: fastestmirror, presto
Setting up Install Process
Loading mirror speeds from cached hostfile
* base: ftp.heanet.ie
* epel: ftp.heanet.ie
* extras: ftp.heanet.ie
* ius: mirrors.ircam.fr
* updates: ftp.heanet.ie
Resolving Dependencies
--> Running transaction check
---> Package php-xml.x86_64 0:5.3.3-49.el6 will be installed
--> Processing Dependency: php-common(x86-64) = 5.3.3-49.el6 for package: php-xml-5.3.3-49.el6.x86_64
--> Processing Dependency: libxslt.so.1(LIBXML2_1.0.24)(64bit) for package: php-xml-5.3.3-49.el6.x86_64
--> Processing Dependency: libxslt.so.1(LIBXML2_1.0.22)(64bit) for package: php-xml-5.3.3-49.el6.x86_64
--> Processing Dependency: libxslt.so.1(LIBXML2_1.0.18)(64bit) for package: php-xml-5.3.3-49.el6.x86_64
--> Processing Dependency: libxslt.so.1(LIBXML2_1.0.13)(64bit) for package: php-xml-5.3.3-49.el6.x86_64
--> Processing Dependency: libxslt.so.1(LIBXML2_1.0.11)(64bit) for package: php-xml-5.3.3-49.el6.x86_64
--> Processing Dependency: libxslt.so.1()(64bit) for package: php-xml-5.3.3-49.el6.x86_64
--> Processing Dependency: libexslt.so.0()(64bit) for package: php-xml-5.3.3-49.el6.x86_64
--> Running transaction check
---> Package libxslt.x86_64 0:1.1.26-2.el6_3.1 will be installed
---> Package php-common.x86_64 0:5.3.3-49.el6 will be installed
--> Processing Conflict: php70u-common-7.0.20-1.ius.centos6.x86_64 conflicts php-common < 7.0.20
--> Processing Conflict: php70u-json-7.0.20-1.ius.centos6.x86_64 conflicts php-json < 7.0.20
--> Finished Dependency Resolution
Error: php70u-common conflicts with php-common-5.3.3-49.el6.x86_64
Error: php70u-json conflicts with php-common-5.3.3-49.el6.x86_64
You could try using --skip-broken to work around the problem
You could try running: rpm -Va --nofiles --nodigest
我已经安装了php70u-common，但如何避免与php-common-5.3.3-49发生冲突？
提前致谢
答案 0 :(得分：2)
如评论所述，安装php70u-xml解决了这个问题。