---------------------------------------------------------Ubuntu----------------------------------------------------------
1.安装pip
sudo apt-get install python3-dev
sudo apt install python3-pip
2.安装virtualenv工具
sudo apt-get install python-virtualenv
3.在工程目录下使用virtualenv工具创建虚拟环境，此时文件夹中将会出现一个venv文件夹
virtualenv -p /usr/bin/python3 py3env
4.激活虚拟环境
. py3env/bin/activate
---------------------------------------------------------CentOS----------------------------------------------------------
1.编译安装
yum -y install zlib-devel bzip2-devel openssl-devel ncurses-devel sqlite-devel tk-devel readline-devel xz-devel
yum install gcc-c++ gcc -y
wget https://www.python.org/ftp/python/3.6.8/Python-3.6.8.tgz
tar -xzvf Python-3.6.8.tgz
cd Python-3.6.8
./configure --prefix=/usr/local --enable-shared --enable-profiling
make -j 4
make install
ln -s /usr/local/python3/bin/python3.6 /usr/local/bin/python3
2.安装virtualenv工具
pip3 install virtualenv