Java的System对象的Properties里所有的内容信息：

Java的System类在开始“Hello World”的时候就是经常用到的，关于System类里的Properties又知道多少呢？

默认System.Properties会给我们封装一些基本的键值对信息

我们就通过代码来看看吧

package com.burns.javafx_study.test;

import java.util.Properties;
import java.util.Set;

public class System_Properties {

public static void main(String[] args) {
Properties properties = System.getProperties();
Set<Object> keys = properties.keySet();
for (Object key : keys) {
Object value = properties.get(key);
System.out.println(key+"====="+value);
}
System.out.println(properties);

}

}
得到的结果如下：
java.runtime.name=====Java(TM) SE Runtime Environment
sun.boot.library.path=====E:\Program Files\Java\jdk1.6.0_45\jre\bin
java.vm.version=====20.45-b01
java.vm.vendor=====Sun Microsystems Inc.
java.vendor.url=====http://java.sun.com/
path.separator=====;
java.vm.name=====Java HotSpot(TM) 64-Bit Server VM
file.encoding.pkg=====sun.io
sun.java.launcher=====SUN_STANDARD
user.country=====CN
sun.os.patch.level=====Service Pack 1
java.vm.specification.name=====Java Virtual Machine Specification
user.dir=====D:\Users\Administrator\workspace\javafx_study
java.runtime.version=====1.6.0_45-b06
java.awt.graphicsenv=====sun.awt.Win32GraphicsEnvironment
java.endorsed.dirs=====E:\Program Files\Java\jdk1.6.0_45\jre\lib\endorsed
os.arch=====amd64
java.io.tmpdir=====C:\Users\ADMINI~1\AppData\Local\Temp\
line.separator=====

java.vm.specification.vendor=====Sun Microsystems Inc.
user.variant=====
os.name=====Windows 7
sun.jnu.encoding=====GBK
java.library.path====="path环境变量的值，太多我就不粘贴了“”.
java.specification.name=====Java Platform API Specification
java.class.version=====50.0
sun.management.compiler=====HotSpot 64-Bit Tiered Compilers
os.version=====6.1
user.home=====C:\Users\Administrator
user.timezone=====
java.awt.printerjob=====sun.awt.windows.WPrinterJob
file.encoding=====GBK
java.specification.version=====1.6
java.class.path=====D:\Users\Administrator\workspace\javafx_study\bin
user.name=====Administrator
java.vm.specification.version=====1.0
sun.java.command=====com.burns.javafx_study.test.System_Properties
java.home=====E:\Program Files\Java\jdk1.6.0_45\jre
sun.arch.data.model=====64
user.language=====zh
java.specification.vendor=====Sun Microsystems Inc.
awt.toolkit=====sun.awt.windows.WToolkit
java.vm.info=====mixed mode
java.version=====1.6.0_45
java.ext.dirs=====E:\Program Files\Java\jdk1.6.0_45\jre\lib\ext;C:\Windows\Sun\Java\lib\ext
sun.boot.class.path=====E:\Program Files\Java\jdk1.6.0_45\jre\lib\resources.jar;E:\Program Files\Java\jdk1.6.0_45\jre\lib\rt.jar;E:\Program Files\Java\jdk1.6.0_45\jre\lib\sunrsasign.jar;E:\Program Files\Java\jdk1.6.0_45\jre\lib\jsse.jar;E:\Program Files\Java\jdk1.6.0_45\jre\lib\jce.jar;E:\Program Files\Java\jdk1.6.0_45\jre\lib\charsets.jar;E:\Program Files\Java\jdk1.6.0_45\jre\lib\modules\jdk.boot.jar;E:\Program Files\Java\jdk1.6.0_45\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=====windows
sun.cpu.isalist=====amd64


当然除了默认的这些，我们还可以自己添加键值对信息，并且使用他们。
package com.burns.javafx_study.test;

import java.util.Properties;
import java.util.Set;

public class System_Properties {

public static void main(String[] args) {
Properties properties = System.getProperties();
// Set<Object> keys = properties.keySet();
// for (Object key : keys) {
// Object value = properties.get(key);
// System.out.println(key+"====="+value);
// }
System.out.println("----------------------------------------------------------------");
properties.put("name", "$$$$$$$$张三@@@@@@@@@");
Set<Object> keys2 = properties.keySet();
for (Object key : keys2) {
Object value = properties.get(key);
System.out.println(key+"====="+value);
}

}

}


得到的结果如下：
----------------------------------------------------------------
java.runtime.name=====Java(TM) SE Runtime Environment
sun.boot.library.path=====E:\Program Files\Java\jdk1.6.0_45\jre\bin
java.vm.version=====20.45-b01
java.vm.vendor=====Sun Microsystems Inc.
java.vendor.url=====http://java.sun.com/
path.separator=====;
java.vm.name=====Java HotSpot(TM) 64-Bit Server VM
file.encoding.pkg=====sun.io
sun.java.launcher=====SUN_STANDARD
user.country=====CN
sun.os.patch.level=====Service Pack 1
java.vm.specification.name=====Java Virtual Machine Specification
user.dir=====D:\Users\Administrator\workspace\javafx_study
java.runtime.version=====1.6.0_45-b06
java.awt.graphicsenv=====sun.awt.Win32GraphicsEnvironment
java.endorsed.dirs=====E:\Program Files\Java\jdk1.6.0_45\jre\lib\endorsed
os.arch=====amd64
name=====$$$$$$$$张三@@@@@@@@@
java.io.tmpdir=====C:\Users\ADMINI~1\AppData\Local\Temp\
line.separator=====

java.vm.specification.vendor=====Sun Microsystems Inc.
user.variant=====
os.name=====Windows 7
sun.jnu.encoding=====GBK
java.library.path====="path具体内容"
java.specification.name=====Java Platform API Specification
java.class.version=====50.0
sun.management.compiler=====HotSpot 64-Bit Tiered Compilers
os.version=====6.1
user.home=====C:\Users\Administrator
user.timezone=====
java.awt.printerjob=====sun.awt.windows.WPrinterJob
file.encoding=====GBK
java.specification.version=====1.6
java.class.path=====D:\Users\Administrator\workspace\javafx_study\bin
user.name=====Administrator
java.vm.specification.version=====1.0
sun.java.command=====com.burns.javafx_study.test.System_Properties
java.home=====E:\Program Files\Java\jdk1.6.0_45\jre
sun.arch.data.model=====64
user.language=====zh
java.specification.vendor=====Sun Microsystems Inc.
awt.toolkit=====sun.awt.windows.WToolkit
java.vm.info=====mixed mode
java.version=====1.6.0_45
java.ext.dirs=====E:\Program Files\Java\jdk1.6.0_45\jre\lib\ext;C:\Windows\Sun\Java\lib\ext
sun.boot.class.path=====E:\Program Files\Java\jdk1.6.0_45\jre\lib\resources.jar;E:\Program Files\Java\jdk1.6.0_45\jre\lib\rt.jar;E:\Program Files\Java\jdk1.6.0_45\jre\lib\sunrsasign.jar;E:\Program Files\Java\jdk1.6.0_45\jre\lib\jsse.jar;E:\Program Files\Java\jdk1.6.0_45\jre\lib\jce.jar;E:\Program Files\Java\jdk1.6.0_45\jre\lib\charsets.jar;E:\Program Files\Java\jdk1.6.0_45\jre\lib\modules\jdk.boot.jar;E:\Program Files\Java\jdk1.6.0_45\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=====windows
sun.cpu.isalist=====amd64