Key Meaning
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"file.separator" File separator (e.g., "/")
"java.class.path" Java classpath
"java.class.version" Java class version number
"java.home" Java installation directory
"java.vendor" Java vendor-specific string
"java.vendor.url" Java vendor URL
"java.version" Java version number
"line.separator" Line separator
"os.arch" Operating system architecture
"os.name" Operating system name
"path.separator" Path separator (e.g., ":")
"user.dir" User‘s current working directory
"user.home" User home directory
"user.name" User account name
原文：http://www.cnblogs.com/svennee/p/4082867.html