软件包“ ttf-mscorefonts-installer”没有安装候选

我在Amazon EC2 Ubuntu服务器中运行了基于Java的Web应用程序。我使用Jasper报告来生成一些PDF格式的报告。我使用“ Jaspersoft Studio”构建了这些报告

现在，当我尝试生成报告时，出现此错误

net.sf.jasperreports.engine.util.jrfontnotfoundexception font 'Times New Roman' is not available to the jvm

因此，我决定安装Microsoft字体。我打过

sudo apt-get install ttf-mscorefonts-installer

它根本没有用。相反，它给了我以下通知

$ sudo apt-get install ttf-mscorefonts-installer
Reading package lists... Done
Building dependency tree
Reading state information... Done
Package ttf-mscorefonts-installer is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source

E: Package 'ttf-mscorefonts-installer' has no installation candidate

我该如何解决这个问题？

更新

我的source.list包含在下面。我可以安全编辑吗？

       ## Note, this file is written by cloud-init on first boot of an instance
## modifications made here will not survive a re-bundle.
## if you wish to make changes you can:
## a.) add 'apt_preserve_sources_list: true' to /etc/cloud/cloud.cfg
##     or do the same in user-data
## b.) add sources in /etc/apt/sources.list.d
## c.) make changes to template file /etc/cloud/templates/sources.list.tmpl
#

# See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to
# newer versions of the distribution.
deb http://us-west-2.ec2.archive.ubuntu.com/ubuntu/ trusty main
deb-src http://us-west-2.ec2.archive.ubuntu.com/ubuntu/ trusty main

## Major bug fix updates produced after the final release of the
## distribution.
deb http://us-west-2.ec2.archive.ubuntu.com/ubuntu/ trusty-updates main
deb-src http://us-west-2.ec2.archive.ubuntu.com/ubuntu/ trusty-updates main

## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
## team. Also, please note that software in universe WILL NOT receive any
## review or updates from the Ubuntu security team.
deb http://us-west-2.ec2.archive.ubuntu.com/ubuntu/ trusty universe
deb-src http://us-west-2.ec2.archive.ubuntu.com/ubuntu/ trusty universe
deb http://us-west-2.ec2.archive.ubuntu.com/ubuntu/ trusty-updates universe
deb-src http://us-west-2.ec2.archive.ubuntu.com/ubuntu/ trusty-updates universe

## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
## team, and may not be under a free licence. Please satisfy yourself as to
## your rights to use the software. Also, please note that software in
## multiverse WILL NOT receive any review or updates from the Ubuntu
## security team.
# deb http://us-west-2.ec2.archive.ubuntu.com/ubuntu/ trusty multiverse
# deb-src http://us-west-2.ec2.archive.ubuntu.com/ubuntu/ trusty multiverse
# deb http://us-west-2.ec2.archive.ubuntu.com/ubuntu/ trusty-updates multiverse
# deb-src http://us-west-2.ec2.archive.ubuntu.com/ubuntu/ trusty-updates multiverse

## Uncomment the following two lines to add software from the 'backports'
## repository.
## N.B. software from this repository may not have been tested as
## extensively as that contained in the main release, although it includes
## newer versions of some applications which may provide useful features.
## Also, please note that software in backports WILL NOT receive any review
## or updates from the Ubuntu security team.
# deb http://us-west-2.ec2.archive.ubuntu.com/ubuntu/ trusty-backports main restricted universe multiverse
# deb-src http://us-west-2.ec2.archive.ubuntu.com/ubuntu/ trusty-backports main restricted universe multiverse

## Uncomment the following two lines to add software from Canonical's
## 'partner' repository.
## This software is not part of Ubuntu, but is offered by Canonical and the
## respective vendors as a service to Ubuntu users.
# deb http://archive.canonical.com/ubuntu trusty partner
# deb-src http://archive.canonical.com/ubuntu trusty partner

deb http://security.ubuntu.com/ubuntu trusty-security main