RStudio安装package时出现错误

Question

> install.packages("ggplot2")
Warning in install.packages :
  InternetOpenUrl failed: ''
Warning in install.packages :
  InternetOpenUrl failed: ''
Warning in install.packages :
  unable to access index for repository https://cran.rstudio.com/src/contrib:
  cannot open URL 'https://cran.rstudio.com/src/contrib/PACKAGES'
Warning in install.packages :
  InternetOpenUrl failed: ''
Warning in install.packages :
  InternetOpenUrl failed: ''
Warning in install.packages :
  unable to access index for repository http://www.stats.ox.ac.uk/pub/RWin/src/contrib:
  cannot open URL 'http://www.stats.ox.ac.uk/pub/RWin/src/contrib/PACKAGES'
Warning in install.packages :
  InternetOpenUrl failed: ''
Warning in install.packages :
  InternetOpenUrl failed: ''
Warning in install.packages :
  unable to access index for repository https://cran.rstudio.com/src/contrib:
  cannot open URL 'https://cran.rstudio.com/src/contrib/PACKAGES'
Warning in install.packages :
  InternetOpenUrl failed: ''
Warning in install.packages :
  InternetOpenUrl failed: ''
Warning in install.packages :
  unable to access index for repository http://www.stats.ox.ac.uk/pub/RWin/src/contrib:
  cannot open URL 'http://www.stats.ox.ac.uk/pub/RWin/src/contrib/PACKAGES'
Warning in install.packages :
  package ‘ggplot2’ is not available (for R version 3.3.2)
Warning in install.packages :
  InternetOpenUrl failed: ''
Warning in install.packages :
  InternetOpenUrl failed: ''
Warning in install.packages :
  unable to access index for repository https://cran.rstudio.com/bin/windows/contrib/3.3:
  cannot open URL 'https://cran.rstudio.com/bin/windows/contrib/3.3/PACKAGES'
Warning in install.packages :
  InternetOpenUrl failed: ''
Warning in install.packages :
  InternetOpenUrl failed: ''
Warning in install.packages :
  unable to access index for repository http://www.stats.ox.ac.uk/pub/RWin/bin/windows/contrib/3.3:
  cannot open URL 'http://www.stats.ox.ac.uk/pub/RWin/bin/windows/contrib/3.3/PACKAGES'
>

请问如何解决

Answer 1

换国内源 因为默认源是国外的 gfw 你懂得

Answer 2

提示是打不开链接，你切换为国内的源试试
Rstudio设置如下
Tools>global options>packages