Where's the problem out of here? How can I download the installation package can be wrong!

General
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1 
setwd('D:\\Download\\R语言学习') 
install.packages('ggmap')
#  install.packages('rgdal')
#  install.packages('maps')
#  install.packages('dplyr')
library(ggmap)
library(rgdal)
library(maps)
library(dplyr)

Warning in install.packages :
downloaded length 2146039 != reported length 4769436
Warning in install.packages :
URL 'https://mirrors.zju.edu.cn/CRAN/bin/windows/contrib/4.4/ggmap_4.0.0.zip': Timeout of 60 seconds was reached
Error in download.file(url, destfile, method, mode = "wb", ...) :
download from 'https://mirrors.zju.edu.cn/CRAN/bin/windows/contrib/4.4/ggmap_4.0.0.zip' failed
Warning in install.packages :
下载程序包‘ggmap’时出了问题

2

It looks like the server might have been having problems. You should try again, and if the server continues to struggle then try switching to a different CRAN mirror.