java中获取系统属性以及环境变量

java中获取系统属性以及环境变量 System.getEnv()和 System.getProperties()的区别 从概念上讲，系统属性 和环境变量 都是名称与值之间的映射。两种机制都能用来将用户定义的信息传递给 Java 进程。环境变量产生更多的全局效应，因为它们不仅对Java 子进程可见，而且对于定义它们的进程的所有子进程都是可见的。在不同的操作系统上，它们的语义有细微的差别，比如，不区分大小写。因为这些原因，环境变量更可能有意料不到的副作用。最好在可能的地方使用系统属性。环境变量应该在需要全局效应的时候使用，或者在外部系统接口要求使用环境变量时使用(比如 PATH)。 代码如下: public static void main(String [] args) { Map m = System.getenv(); for ( Iterator it = m.keySet().iterator(); it.hasNext(); ) { String key = (String ) it.next(); String value = (String ) m.get(key); System.out.println(key +":" +value); } System.out.println( "--------------------------------------" ); Properties p = System.getProperties(); for ( Iterator it = p.keySet().iterator(); it.hasNext(); ) { String key = (String ) it.next(); String value = (String ) p.get(key); System.out.println(key +":" +value); } } 输入如下: ANT_HOME:D:/program/devel/ant PROCESSOR_ARCHITECTURE:x86 LOGONSERVER://RJ-WEIJIANJUN HOMEDRIVE:C: CATALINA_HOME:D:/program/server/Tomcat5.5 DXSDK_DIR:d:/Program Files/Microsoft DirectX SDK (August 2008)/ VS80COMNTOOLS:C:/Program Files/Microsoft Visual Studio 8/Common7/Tools/ SESSIONNAME:Console HOMEPATH:/Documents and Settings/Administrator TMP:C:/DOCUME~1/ADMINI~1/LOCALS~1/Temp windir:C:/WINDOWS PROCESSOR_IDENTIFIER:x86 Family 6 Model 15 Stepping 13, GenuineIntel VS90COMNTOOLS:e:/Program Files/Microsoft Visual Studio 9.0/Common7/Tools/ SystemDrive:C: USERPROFILE:C:/Documents and Settings/Administrator PATHEXT:.COM;.EXE;.BAT;.CMD;.VBS;.VBE;.JS;.JSE;.WSF;.WSH CommonProgramFiles:C:/Program Files/Common Files NUMBER_OF_PROCESSORS:2 ComSpec:C:/WINDOWS/system32/cmd.exe COMPUTERNAME:RJ-WEIJIANJUN OS:Windows_NT USERNAME:Administrator CLIENTNAME:Console TEMP:C:/DOCUME~1/ADMINI~1/LOCALS~1/Temp USERDOMAIN:RJ-WEIJIANJUN ALLUSERSPROFILE:C:/Documents and Settings/All Users lib:C:/Program Files/SQLXML 4.0/bin/ PROCESSOR_LEVEL:6 SystemRoot:C:/WINDOWS ClusterLog:C:/WINDOWS/Cluster/cluster.log APPDATA:C:/Documents and Settings/Administrator/Application Data Path:C:/WINDOWS/system32;C:/WINDOWS;C:/WINDOWS/System32/Wbem;C:/Program Files/Microsoft SQL Server/80/Tools/Binn/;C:/Program Files/Microsoft SQL Server/90/DTS/Binn/;C:/Program Files/Microsoft SQL Server/90/Tools/binn/;C:/Program Files/Microsoft SQL Server/90/Tools/Binn/VSShell/Common7/IDE/;C:/Program Files/Microsoft Visual Studio 8/Common7/IDE/PrivateAssemblies/;D:/program/devel/flex_sdk2/bin;D:/program/devel/ant/bin;C:/Program Files/Java/jdk1.6.0_07/bin;%JONAS_ROOT%/bin/nt;d:/program/devel/ant/bin JAVA_HOME:C:/Program Files/Java/jdk1.6.0_07 FP_NO_HOST_CHECK:NO PROCESSOR_REVISION:0f0d ProgramFiles:C:/Program Files 以下是property的输出: -------------------------------------- java.runtime.name:Java(TM) 2 Runtime Environment, Standard Edition sun.boot.library.path:D:/Program Files/MyEclipse 6.5/jre/bin java.vm.version:1.5.0_11-b03 java.vm.vendor:Sun Microsystems Inc. java.vendor.url: path.separator:; java.vm.name:Java HotSpot(TM) Client VM file.encoding.pkg:sun.io sun.java.launcher:SUN_STANDARD user.country:CN sun.os.patch.level:Service Pack 2 java.vm.specification.name:Java Virtual Machine Specification user.dir:D:/dev/eclipse/mye65/workspace/jmx java.runtime.version:1.5.0_11-b03 java.awt.graphicsenv:sun.awt.Win32GraphicsEnvironment java.endorsed.dirs:D:/Program Files/MyEclipse 6.5/jre/lib/endorsed os.arch:x86 java.io.tmpdir:C:/DOCUME~1/ADMINI~1/LOCALS~1/Temp/ line.separator: java.vm.specification.vendor:Sun Microsystems Inc. user.variant: os.name:Windows 2003 sun.jnu.encoding:GBK java.library.path:D:/Program Files/MyEclipse 6.5/jre/bin;.;C:/WINDOWS/system32;C:/WINDOWS;C:/WINDOWS/system32;C:/WINDOWS;C:/WINDOWS/System32/Wbem;C:/Program Files/Microsoft SQL Server/80/Tools/Binn/;C:/Program Files/Microsoft SQL Server/90/DTS/Binn/;C:/Program Files/Microsoft SQL Server/90/Tools/binn/;C:/Program Files/Microsoft SQL Server/90/Tools/Binn/VSShell/Common7/IDE/;C:/Program Files/Microsoft Visual Studio 8/Common7/IDE/PrivateAssemblies/;D:/program/devel/flex_sdk2/bin;D:/program/devel/ant/bin;C:/Program Files/Java/jdk1.6.0_07/bin;%JONAS_ROOT%/bin/nt;d:/program/devel/ant/bin java.specification.name:Java Platform API Specification java.class.version:49.0 sun.management.compiler:HotSpot Client Compiler os.version:5.2 user.home:C:/Documents and Settings/Administrator user.timezone:Asia/Shanghai java.awt.printerjob:sun.awt.windows.WPrinterJob file.encoding:GBK java.specification.version:1.5 java.class.path:D:/dev/eclipse/mye65/workspace/jmx/bin;D:/program/lib/jmx/jmxtools.jar;D:/program/lib/log/commons-logging-1.1.1.jar;D:/program/lib/log/log4j-1.2.15.jar; D:/program/lib/registry/registry.jar user.name:Administrator java.vm.specification.version:1.0 java.home:D:/Program Files/MyEclipse 6.5/jre sun.arch.data.model:32 user.language:zh java.specification.vendor:Sun Microsystems Inc. awt.toolkit:sun.awt.windows.WToolkit java.vm.info:mixed mode java.version:1.5.0_11 java.ext.dirs:D:/Program Files/MyEclipse 6.5/jre/lib/ext sun.boot.class.path:D:/Program Files/MyEclipse 6.5/jre/lib/rt.jar;D:/Program Files/MyEclipse 6.5/jre/lib/i18n.jar;D:/Program Files/MyEclipse 6.5/jre/lib/sunrsasign.jar;D:/Program Files/MyEclipse 6.5/jre/lib/jsse.jar;D:/Program Files/MyEclipse 6.5/jre/lib/jce.jar;D:/Program Files/MyEclipse 6.5/jre/lib/charsets.jar;D:/Program Files/MyEclipse 6.5/jre/classes java.vendor:Sun Microsystems Inc. file.separator:/ java.vendor.url.bug: i-bin/bugreport.cgi sun.io.unicode.encoding:UnicodeLittle sun.cpu.endian:little sun.desktop:windows sun.cpu.isalist:pentium_pro+mmx pentium_pro pentium+mmx pentium i486 i386 i86 个人认为比较重要的系统属性: java.home:Java 安装目录 (比如D:/JavaStudio/jdk15/jre) java.class.path:Java 类路径 java.vm.version:Java虚拟机版本号(比如:1.5.0-b64) java.version:Java版本号(比如:1.5.0) os.name:操作系统的名称(比如:Windows XP) os.version:操作系统的版本(比如:Windows XP 的版本为5.1) user.home:用户的主目录 (比如:C:/Documents and Settings/zhangsan) user.name:当前用户名 user.country:当前用户所属国家 user.dir:用户的当前工作目录 比较重要的环境变量(Windows操作系统): %COMPUTERNAME% 返回计算机的名称。 %COMSPEC% 返回命令行解释器可执行程序的准确路径。 %WINDIR% 返回操作系统目录的位置。 %OS% 返回操作系统的名称。Windows 2000 将操作系统显示为 Windows_NT。 %PATH% 指定可执行文件的搜索路径。 %USERDOMAIN% 返回包含用户帐户的域的名称。 %USERNAME% 返回当前登录的用户的名称。 下面是一篇在jdk1.4中得到环境变量的方法: Access user defined environment variable inside the java program with jdk1.4 In JDK 1.4 System.getenv() is deprecated. (In JDK 1.5 it is un-deprected again.) The getProperty method is now the correspoding method to get the variables. For example: System.getProperty("java.class.path",""). But it doesn't work for user defined environment variable. This problem can be solved by using the following code: import java.io.BufferedReader; import java.io.InputStreamReader; /** * Environment class simulates the System.getenv() method which is deprecated * on java 1.4.2 * * @author v-josp */ public class TestRoot { //result of all enviornment variables private static BufferedReader commandResult; static { String cmd = null; String os = null; //getting the OS name os = System.getProperty("os.name").toLowerCase(); // according to OS set the command to execute if(os.startsWith("windows")) { cmd = "cmd /c SET"; } else { cmd="env"; } try { //execute the command and get the result in the form of InputStream Process p = Runtime.getRuntime().exec(cmd); //parse the InputStream data InputStreamReader isr = new InputStreamReader(p.getInputStream()); commandResult= new BufferedReader(isr); } catch (Exception e) { System.out.println("OSEnvironment.class error: " + cmd + ":" + e); } } /** * This method is used to get the path of the given enviornment variable. This * method tries to simulates the System.getenv() which is deprecated on java 1.4.2 * * @param String - name of the environment variable * @param String - default value * @return */ public static String getenv(String envName,String defaultValue) { String line = null; try { while ((line = commandResult.readLine()) != null) { if(line.indexOf(envName)>-1) { return line.substring(line.indexOf(envName)+envName.length()+1); } } return defaultValue; } catch (Exception e) { return defaultValue; } } public static void main(String args[]) { System.out.println(TestRoot.getenv("CLASSPATH","")); } }