java命令查询属性信息

System.getProperty("user.home")可以查询JAVA系统的user.home属性的值，

除了user.home，还有user.dir, file.separator, file.encoding等，

可以用命令查看：

java -XshowSettings:all -version
java -XshowSettings:vm -version
java -XshowSettings:properties -version
java -XshowSettings:locale -version　

示例：

D:\Users\XXX>java -XshowSettings:all -version
VM settings:
    Max. Heap Size (Estimated): 1.75G
    Ergonomics Machine Class: client
    Using VM: Java HotSpot(TM) 64-Bit Server VM

Property settings:
    awt.toolkit = sun.awt.windows.WToolkit
    file.encoding = GB18030
    file.encoding.pkg = sun.io
    file.separator = \
    java.awt.graphicsenv = sun.awt.Win32GraphicsEnvironment
    java.awt.printerjob = sun.awt.windows.WPrinterJob
    java.class.path = .
        C:\Program Files\Java\jdk1.8.0_92\bin\dt.jar
        C:\Program Files\Java\jdk1.8.0_92\lib\tools.jar
    java.class.version = 52.0
    java.endorsed.dirs = C:\Program Files\Java\jre1.8.0_92\lib\endorsed
    java.ext.dirs = C:\Program Files\Java\jre1.8.0_92\lib\ext
        C:\windows\Sun\Java\lib\ext
    java.home = C:\Program Files\Java\jre1.8.0_92
    java.io.tmpdir = D:\Users\XXX\AppData\Local\Temp\
    java.library.path = C:\ProgramData\Oracle\Java\javapath
        C:\windows\Sun\Java\bin
        C:\windows\system32
        C:\windows
        C:\ProgramData\Oracle\Java\javapath
        C:\windows\system32
        C:\windows
        C:\windows\System32\Wbem
        C:\windows\System32\WindowsPowerShell\v1.0\
        C:\Program Files (x86)\Enterprise Vault\EVClient\
        C:\Program Files\Java\jdk1.8.0_92\bin
        C:\Program Files\Java\jdk1.8.0_92\jre\bin
        D:\Users\XXX\zhangjl\software\Maven\apache-maven-3.5.4\bin
        D:\Users\XXX\zhangjl\software\Git\Git\cmd
        D:\Users\XXX\zhangjl\software\TortoiseGit\bin
        D:\Users\XXX\AppData\Local\Microsoft\WindowsApps

        .
    java.runtime.name = Java(TM) SE Runtime Environment
    java.runtime.version = 1.8.0_92-b14
    java.specification.name = Java Platform API Specification
    java.specification.vendor = Oracle Corporation
    java.specification.version = 1.8
    java.vendor = Oracle Corporation
    java.vendor.url = http://java.oracle.com/
    java.vendor.url.bug = http://bugreport.sun.com/bugreport/
    java.version = 1.8.0_92
    java.vm.info = mixed mode
    java.vm.name = Java HotSpot(TM) 64-Bit Server VM
    java.vm.specification.name = Java Virtual Machine Specification
    java.vm.specification.vendor = Oracle Corporation
    java.vm.specification.version = 1.8
    java.vm.vendor = Oracle Corporation
    java.vm.version = 25.92-b14
    line.separator = \r \n
    os.arch = amd64
    os.name = Windows 10
    os.version = 10.0
    path.separator = ;
    sun.arch.data.model = 64
    sun.boot.class.path = C:\Program Files\Java\jre1.8.0_92\lib\resources.jar
        C:\Program Files\Java\jre1.8.0_92\lib\rt.jar
        C:\Program Files\Java\jre1.8.0_92\lib\sunrsasign.jar
        C:\Program Files\Java\jre1.8.0_92\lib\jsse.jar
        C:\Program Files\Java\jre1.8.0_92\lib\jce.jar
        C:\Program Files\Java\jre1.8.0_92\lib\charsets.jar
        C:\Program Files\Java\jre1.8.0_92\lib\jfr.jar
        C:\Program Files\Java\jre1.8.0_92\classes
    sun.boot.library.path = C:\Program Files\Java\jre1.8.0_92\bin
    sun.cpu.endian = little
    sun.cpu.isalist = amd64
    sun.desktop = windows
    sun.io.unicode.encoding = UnicodeLittle
    sun.java.launcher = SUN_STANDARD
    sun.jnu.encoding = GB18030
    sun.management.compiler = HotSpot 64-Bit Tiered Compilers
    sun.os.patch.level =
    sun.stderr.encoding = ms936
    sun.stdout.encoding = ms936
    user.country = CN
    user.dir = D:\Users\XXX
    user.home = D:\Users\XXX
    user.language = zh
    user.name = XXX
    user.script =
    user.timezone =
    user.variant =

Locale settings:
    default locale = 中文
    default display locale = 中文 (中国)
    default format locale = 中文 (中国)
    available locales = , ar, ar_AE, ar_BH, ar_DZ, ar_EG, ar_IQ, ar_JO,
        ar_KW, ar_LB, ar_LY, ar_MA, ar_OM, ar_QA, ar_SA, ar_SD,
        ar_SY, ar_TN, ar_YE, be, be_BY, bg, bg_BG, ca,
        ca_ES, cs, cs_CZ, da, da_DK, de, de_AT, de_CH,
        de_DE, de_GR, de_LU, el, el_CY, el_GR, en, en_AU,
        en_CA, en_GB, en_IE, en_IN, en_MT, en_NZ, en_PH, en_SG,
        en_US, en_ZA, es, es_AR, es_BO, es_CL, es_CO, es_CR,
        es_CU, es_DO, es_EC, es_ES, es_GT, es_HN, es_MX, es_NI,
        es_PA, es_PE, es_PR, es_PY, es_SV, es_US, es_UY, es_VE,
        et, et_EE, fi, fi_FI, fr, fr_BE, fr_CA, fr_CH,
        fr_FR, fr_LU, ga, ga_IE, hi, hi_IN, hr, hr_HR,
        hu, hu_HU, in, in_ID, is, is_IS, it, it_CH,
        it_IT, iw, iw_IL, ja, ja_JP, ja_JP_JP_#u-ca-japanese, ko, ko_KR,
        lt, lt_LT, lv, lv_LV, mk, mk_MK, ms, ms_MY,
        mt, mt_MT, nl, nl_BE, nl_NL, no, no_NO, no_NO_NY,
        pl, pl_PL, pt, pt_BR, pt_PT, ro, ro_RO, ru,
        ru_RU, sk, sk_SK, sl, sl_SI, sq, sq_AL, sr,
        sr_BA, sr_BA_#Latn, sr_CS, sr_ME, sr_ME_#Latn, sr_RS, sr_RS_#Latn, sr__#Latn,
        sv, sv_SE, th, th_TH, th_TH_TH_#u-nu-thai, tr, tr_TR, uk,
        uk_UA, vi, vi_VN, zh, zh_CN, zh_HK, zh_SG, zh_TW

java version "1.8.0_92"
Java(TM) SE Runtime Environment (build 1.8.0_92-b14)
Java HotSpot(TM) 64-Bit Server VM (build 25.92-b14, mixed mode)

D:\Users\XXX>