System.getProperty("line.separator");
在这个平台下行与行之间的分隔符
相当于“/n”
还有很多其它参数
os.name Operating system name
os.arch Operating system architecture
os.version Operating system version
file.separator File separator ("/" on UNIX)
path.separator Path separator (":" on UNIX)
line.separator Line separator ("/n" on UNIX)
user.name User's account name
user.home User's home directory
user.dir User's current working directory