问题描述
我完全迷失了这个：System.getProperty("user.home")和System.getProperty("user.name")返回问号”?”。
System-Specs:
Kubuntu 9.04
Gnome 2.2.61
Java 1.5.0_16
我的测试用例看起来像这样：
$ more Test.java
class Test { public static void main( String[] args ) { System.out.println( System.getProperties() ); } }
结果是(为了更好的可读性，添加了line-breaks，替换了公司名称和自己的名字)：
$ javac Test.java
$ java Test
{
java.runtime.name=Java(TM) 2 Runtime Environment, Standard Edition,
sun.boot.library.path=/home/MYCOMPANY/myname/apps/jdk1.5.0_16/jre/lib/i386,
java.vm.version=1.5.0_16-b02,
java.vm.vendor=Sun Microsystems Inc.,
java.vendor.url=http://java.sun.com/,
path.separator=:,
java.vm.name=Java HotSpot(TM) Server VM,
file.encoding.pkg=sun.io,
sun.java.launcher=SUN_STANDARD,
user.country=US,
sun.os.patch.level=unknown,
java.vm.specification.name=Java Virtual Machine Specification,
user.dir=/home/MYCOMPANY/myname/temp,
java.runtime.version=1.5.0_16-b02,
java.awt.graphicsenv=sun.awt.X11GraphicsEnvironment,
java.endorsed.dirs=/home/MYCOMPANY/myname/apps/jdk1.5.0_16/jre/lib/endorsed,
os.arch=i386,
java.io.tmpdir=/tmp,
line.separator=
,
java.vm.specification.vendor=Sun Microsystems Inc.,
os.name=Linux,
sun.jnu.encoding=UTF-8,
java.library.path=/home/MYCOMPANY/myname/apps/jdk1.5.0_16/jre/lib/i386/server:/home/MYCOMPANY/myname/apps/jdk1.5.0_16/jre/lib/i386:/home/MYCOMPANY/myname/apps/jdk1.5.0_16/jre/../lib/i386,
java.specification.name=Java Platform API Specification,
java.class.version=49.0,
sun.management.compiler=HotSpot Server Compiler,
os.version=2.6.28-15-generic,
user.home=?,
user.timezone=,
java.awt.printerjob=sun.print.PSPrinterJob,
file.encoding=UTF-8,
java.specification.version=1.5,
java.class.path=.,
user.name=?,
java.vm.specification.version=1.0,
java.home=/home/MYCOMPANY/myname/apps/jdk1.5.0_16/jre,
sun.arch.data.model=32,
user.language=en,
java.specification.vendor=Sun Microsystems Inc.,
java.vm.info=mixed mode,
java.version=1.5.0_16,
java.ext.dirs=/home/MYCOMPANY/myname/apps/jdk1.5.0_16/jre/lib/ext,
sun.boot.class.path=/home/MYCOMPANY/myname/apps/jdk1.5.0_16/jre/lib/rt.jar:/home/MYCOMPANY/myname/apps/jdk1.5.0_16/jre/lib/i18n.jar:/home/MYCOMPANY/myname/apps/jdk1.5.0_16/jre/lib/sunrsasign.jar:/home/MYCOMPANY/myname/apps/jdk1.5.0_16/jre/lib/jsse.jar:/home/MYCOMPANY/myname/apps/jdk1.5.0_16/jre/lib/jce.jar:/home/MYCOMPANY/myname/apps/jdk1.5.0_16/jre/lib/charsets.jar:/home/MYCOMPANY/myname/apps/jdk1.5.0_16/jre/classes,
java.vendor=Sun Microsystems Inc.,
file.separator=/,
java.vendor.url.bug=http://java.sun.com/cgi-bin/bugreport.cgi,
sun.io.unicode.encoding=UnicodeLittle,
sun.cpu.endian=little,
sun.desktop=gnome,
sun.cpu.isalist=
}
有人经历过吗？ Java在哪里寻找用户和主目录？我已经检查了正确设置的HOME环境变量。
最佳解决方法
这有点令人尴尬，但解决方案只是在64位系统上使用64位JDK。我从旧机器复制了所有内容，这也意味着32位JDK，这就是问题所在。它按预期工作，具有64位运行时。
很抱歉打扰。
次佳解决方法
解决方法，而不是解决方案。您应该可以通过添加-Duser.home=$HOME作为参数来设置它。
java -Duser.home=$HOME Test
第三种解决方法
其他有保障的属性怎么样？如果您调用类似于以下内容的电话会怎样？
public static void printAllGuaranteedProperties() {
printAProperty ("java.version", "Java version number");
printAProperty ("java.vendor", "Java vendor specific string");
printAProperty ("java.vendor.url", "Java vendor URL");
printAProperty ("java.home", "Java installation directory");
printAProperty ("java.class.version", "Java class version number");
printAProperty ("java.class.path", "Java classpath");
printAProperty ("os.name", "Operating System Name");
printAProperty ("os.arch", "Operating System Architecture");
printAProperty ("os.version", "Operating System Version");
printAProperty ("file.separator", "File separator");
printAProperty ("path.separator", "Path separator");
printAProperty ("line.separator", "Line separator");
printAProperty ("user.name", "User account name");
printAProperty ("user.home", "User home directory");
printAProperty ("user.dir", "User's current working directory");
}
public static void printAProperty (String propName, String desc) {
System.out.println ("Value for '" + desc + "' is '" + System.getProperty(propName) + "'.");
}
第四种方法
wds在他/她的评论中是正确的。 user.home值似乎取自/etc /passwd。您在/etc/passwd中为您的用户做什么？
如果将条目更改为/home/nonexisting，则Test类将打印/home/nonexisting。你碰巧在/etc /passwd中有?吗？