有用

System.getProperties().list(System.out);

-- listing properties --
java.runtime.name=Java(TM) SE Runtime Environment
sun.boot.library.path=C:\Program Files\Java\jdk1.7.0_17\jre...
java.vm.version=23.7-b01
java.vm.vendor=Oracle Corporation
java.vendor.url=http://java.oracle.com/
path.separator=;
java.vm.name=Java HotSpot(TM) Client VM
file.encoding.pkg=sun.io
user.script=
user.country=CN
sun.java.launcher=SUN_STANDARD
sun.os.patch.level=Service Pack 3
java.vm.specification.name=Java Virtual Machine Specification
user.dir=F:\icss\2013312\eclipse\workspace\J2S...
java.runtime.version=1.7.0_17-b02
java.awt.graphicsenv=sun.awt.Win32GraphicsEnvironment
java.endorsed.dirs=C:\Program Files\Java\jdk1.7.0_17\jre...
os.arch=x86
java.io.tmpdir=C:\DOCUME~1\ADMINI~1\LOCALS~1\Temp\
line.separator=

java.vm.specification.vendor=Oracle Corporation
user.variant=
os.name=Windows XP
sun.jnu.encoding=GBK
java.library.path=C:\Program Files\Java\jdk1.7.0_17\bin...
java.specification.name=Java Platform API Specification
java.class.version=51.0
sun.management.compiler=HotSpot Client Compiler
os.version=5.1
user.home=C:\Documents and Settings\Administrator
user.timezone=
java.awt.printerjob=sun.awt.windows.WPrinterJob
file.encoding=utf-8
java.specification.version=1.7
user.name=Administrator
java.class.path=F:\icss\2013312\eclipse\workspace\J2S...
java.vm.specification.version=1.7
sun.arch.data.model=32
java.home=C:\Program Files\Java\jdk1.7.0_17\jre
sun.java.command=com.fidelity.io.Test
java.specification.vendor=Oracle Corporation
user.language=zh
awt.toolkit=sun.awt.windows.WToolkit
java.vm.info=mixed mode, sharing
java.version=1.7.0_17
java.ext.dirs=C:\Program Files\Java\jdk1.7.0_17\jre...
sun.boot.class.path=C:\Program Files\Java\jdk1.7.0_17\jre...
java.vendor=Oracle Corporation
file.separator=\
java.vendor.url.bug=http://bugreport.sun.com/bugreport/
sun.cpu.endian=little
sun.io.unicode.encoding=UnicodeLittle
sun.desktop=windows
sun.cpu.isalist=pentium_pro+mmx pentium_pro pentium+m...