Java 通过getProperties()获取系统属性值，参数值

System.getProperties()获得系统的所有属性值，然后返回一个Properties属性的集合。

里面存放的是属性和属性值的关系映射，包括默认的编码方式。简单演示如下

获取系统属性值

import java.util.Map.Entry;import java.util.Properties;import java.util.Set;//获取系统所有属性public class SystemPropertiesDemo {public static void main(String[] args) {Properties pro = System.getProperties();// 打印所有的键值对Set<Entry<Object, Object>> entrySet =  pro.entrySet();for (Entry<Object, Object> entry : entrySet) {System.out.println(entry.getKey()+" = "+entry.getValue());}}}

运行结果：

java.runtime.name = Java(TM) SE Runtime Environmentsun.boot.library.path = C:\Program Files\Java\jdk1.8.0_121\jre\binjava.vm.version = 25.121-b13java.vm.vendor = Oracle Corporationjava.vendor.url = http://java.oracle.com/path.separator = ;java.vm.name = Java HotSpot(TM) 64-Bit Server VMfile.encoding.pkg = sun.iouser.country = CNuser.script = sun.java.launcher = SUN_STANDARDsun.os.patch.level = java.vm.specification.name = Java Virtual Machine Specificationuser.dir = D:\eclipsesWorkspace\IO流java.runtime.version = 1.8.0_121-b13java.awt.graphicsenv = sun.awt.Win32GraphicsEnvironmentjava.endorsed.dirs = C:\Program Files\Java\jdk1.8.0_121\jre\lib\endorsedos.arch = amd64java.io.tmpdir = C:\Users\30382\AppData\Local\Temp\line.separator = java.vm.specification.vendor = Oracle Corporationuser.variant = os.name = Windows 10sun.jnu.encoding = GBKjava.library.path = C:\Program Files\Java\jdk1.8.0_121\bin;C:\Windows\Sun\Java\bin;C:\Windows\system32;C:\Windows;C:/Program Files/Java/jre1.8.0_121/bin/server;C:/Program Files/Java/jre1.8.0_121/bin;C:/Program Files/Java/jre1.8.0_121/lib/amd64;C:\ProgramData\Oracle\Java\javapath;C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Windows\System32\WindowsPowerShell\v1.0\;D:\Program Files\Microsoft SQL Server\110\DTS\Binn\;D:\Program Files (x86)\Microsoft SQL Server\110\Tools\Binn\;D:\Program Files\Microsoft SQL Server\110\Tools\Binn\;D:\Program Files (x86)\Microsoft SQL Server\110\Tools\Binn\ManagementStudio\;C:\Program Files (x86)\Microsoft Visual Studio 10.0\Common7\IDE\PrivateAssemblies\;D:\Program Files (x86)\Microsoft SQL Server\110\DTS\Binn\;C:\Program Files\Git\cmd;C:\Users\30382\AppData\Local\Microsoft\WindowsApps;C:\Program Files\Java\jdk1.8.0_121\bin;C:\Program Files\Java\jdk1.8.0_121\jre\bin;;D:\eclipse;;.java.specification.name = Java Platform API Specificationjava.class.version = 52.0sun.management.compiler = HotSpot 64-Bit Tiered Compilersos.version = 10.0user.home = C:\Users\30382user.timezone = java.awt.printerjob = sun.awt.windows.WPrinterJobfile.encoding = GBKjava.specification.version = 1.8java.class.path = D:\eclipsesWorkspace\IO流\binuser.name = 30382java.vm.specification.version = 1.8sun.java.command = _02_fileStream.SystemPropertiesDemojava.home = C:\Program Files\Java\jdk1.8.0_121\jresun.arch.data.model = 64user.language = zhjava.specification.vendor = Oracle Corporationawt.toolkit = sun.awt.windows.WToolkitjava.vm.info = mixed modejava.version = 1.8.0_121java.ext.dirs = C:\Program Files\Java\jdk1.8.0_121\jre\lib\ext;C:\Windows\Sun\Java\lib\extsun.boot.class.path = C:\Program Files\Java\jdk1.8.0_121\jre\lib\resources.jar;C:\Program Files\Java\jdk1.8.0_121\jre\lib\rt.jar;C:\Program Files\Java\jdk1.8.0_121\jre\lib\sunrsasign.jar;C:\Program Files\Java\jdk1.8.0_121\jre\lib\jsse.jar;C:\Program Files\Java\jdk1.8.0_121\jre\lib\jce.jar;C:\Program Files\Java\jdk1.8.0_121\jre\lib\charsets.jar;C:\Program Files\Java\jdk1.8.0_121\jre\lib\jfr.jar;C:\Program Files\Java\jdk1.8.0_121\jre\classesjava.vendor = Oracle Corporationfile.separator = \java.vendor.url.bug = http://bugreport.sun.com/bugreport/sun.io.unicode.encoding = UnicodeLittlesun.cpu.endian = littlesun.desktop = windowssun.cpu.isalist = amd64

获取系统参数：

import java.util.Properties;public class SystemPropertiesDemo {public static void main(String[] args) {Properties props=System.getProperties(); //系统属性    System.out.println("Java的运行环境版本："+props.getProperty("java.version"));    System.out.println("Java的运行环境供应商："+props.getProperty("java.vendor"));    System.out.println("Java供应商的URL："+props.getProperty("java.vendor.url"));    System.out.println("Java的安装路径："+props.getProperty("java.home"));    System.out.println("Java的虚拟机规范版本："+props.getProperty("java.vm.specification.version"));    System.out.println("Java的虚拟机规范供应商："+props.getProperty("java.vm.specification.vendor"));    System.out.println("Java的虚拟机规范名称："+props.getProperty("java.vm.specification.name"));    System.out.println("Java的虚拟机实现版本："+props.getProperty("java.vm.version"));    System.out.println("Java的虚拟机实现供应商："+props.getProperty("java.vm.vendor"));    System.out.println("Java的虚拟机实现名称："+props.getProperty("java.vm.name"));    System.out.println("Java运行时环境规范版本："+props.getProperty("java.specification.version"));    System.out.println("Java运行时环境规范供应商："+props.getProperty("java.specification.vender"));    System.out.println("Java运行时环境规范名称："+props.getProperty("java.specification.name"));    System.out.println("Java的类格式版本号："+props.getProperty("java.class.version"));    System.out.println("Java的类路径："+props.getProperty("java.class.path"));    System.out.println("加载库时搜索的路径列表："+props.getProperty("java.library.path"));    System.out.println("默认的临时文件路径："+props.getProperty("java.io.tmpdir"));    System.out.println("一个或多个扩展目录的路径："+props.getProperty("java.ext.dirs"));    System.out.println("操作系统的名称："+props.getProperty("os.name"));    System.out.println("操作系统的构架："+props.getProperty("os.arch"));    System.out.println("操作系统的版本："+props.getProperty("os.version"));    System.out.println("文件分隔符："+props.getProperty("file.separator"));   //在 unix 系统中是＂／＂    System.out.println("路径分隔符："+props.getProperty("path.separator"));   //在 unix 系统中是＂:＂    System.out.println("行分隔符："+props.getProperty("line.separator"));   //在 unix 系统中是＂/n＂    System.out.println("用户的账户名称："+props.getProperty("user.name"));    System.out.println("用户的主目录："+props.getProperty("user.home"));    System.out.println("用户的当前工作目录："+props.getProperty("user.dir"));}}

运行结果：

Java的运行环境版本：1.8.0_121Java的运行环境供应商：Oracle CorporationJava供应商的URL：http://java.oracle.com/Java的安装路径：C:\Program Files\Java\jdk1.8.0_121\jreJava的虚拟机规范版本：1.8Java的虚拟机规范供应商：Oracle CorporationJava的虚拟机规范名称：Java Virtual Machine SpecificationJava的虚拟机实现版本：25.121-b13Java的虚拟机实现供应商：Oracle CorporationJava的虚拟机实现名称：Java HotSpot(TM) 64-Bit Server VMJava运行时环境规范版本：1.8Java运行时环境规范供应商：nullJava运行时环境规范名称：Java Platform API SpecificationJava的类格式版本号：52.0Java的类路径：D:\eclipsesWorkspace\IO流\bin加载库时搜索的路径列表：C:\Program Files\Java\jdk1.8.0_121\bin;C:\Windows\Sun\Java\bin;C:\Windows\system32;C:\Windows;C:/Program Files/Java/jre1.8.0_121/bin/server;C:/Program Files/Java/jre1.8.0_121/bin;C:/Program Files/Java/jre1.8.0_121/lib/amd64;C:\ProgramData\Oracle\Java\javapath;C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Windows\System32\WindowsPowerShell\v1.0\;D:\Program Files\Microsoft SQL Server\110\DTS\Binn\;D:\Program Files (x86)\Microsoft SQL Server\110\Tools\Binn\;D:\Program Files\Microsoft SQL Server\110\Tools\Binn\;D:\Program Files (x86)\Microsoft SQL Server\110\Tools\Binn\ManagementStudio\;C:\Program Files (x86)\Microsoft Visual Studio 10.0\Common7\IDE\PrivateAssemblies\;D:\Program Files (x86)\Microsoft SQL Server\110\DTS\Binn\;C:\Program Files\Git\cmd;C:\Users\30382\AppData\Local\Microsoft\WindowsApps;C:\Program Files\Java\jdk1.8.0_121\bin;C:\Program Files\Java\jdk1.8.0_121\jre\bin;;D:\eclipse;;.默认的临时文件路径：C:\Users\30382\AppData\Local\Temp\一个或多个扩展目录的路径：C:\Program Files\Java\jdk1.8.0_121\jre\lib\ext;C:\Windows\Sun\Java\lib\ext操作系统的名称：Windows 10操作系统的构架：amd64操作系统的版本：10.0文件分隔符：\路径分隔符：;行分隔符：用户的账户名称：30382用户的主目录：C:\Users\30382用户的当前工作目录：D:\eclipsesWorkspace\IO流