在Java中如何读取Windows的环境变量?!

[dimaomao]

在Java中如何读取Windows的环境变量?!
例如：PATH或者TEMP等等……

[xjx802]

up

[15年老程创业中]

Class System的Doc
getProperties
public static Properties getProperties()Determines the current system properties.
First, if there is a security manager, its checkPropertiesAccess method is called with no arguments. This may result in a security exception.

The current set of system properties for use by the getProperty(String) method is returned as a Properties object. If there is no current set of system properties, a set of system properties is first created and initialized. This set of system properties always includes values for the following keys:
Key Description of Associated Value

java.io.tmpdir Default temp file path
os.name Operating system name
os.arch Operating system architecture
os.version Operating system version
等等

[geyf]

System.out.println("tmpdir:"+System.getProperty("java.io.tmpdir"));//临时目录

要知道有哪些系统属性可获得，可以看看资料，或者自己写个代码看看：
Properties p=System.getProperties();
Enumeration tttt=p.propertyNames();
while( tttt.hasMoreElements())
System.out.println(tttt.nextElement().toString());

[dimaomao]

我需要的是Windows的环境变量,不是system的属性!!
Windows的环境变量例如:"CLASSPATH"、"JAVA_HOME"!!

[lymkelly]

关注

[dimaomao]

Java 不支援环境变数, 因为它们是不具可携性的.
不过我们可以在JAVA里面调用WINDOWS的系统命令"Echo %JAVA_HOME%"取得其输出,在经过处理取得字符串返回值.
程序如下:
package test;
import java.io.*;
import java.util.*;
/**
* <p>Title: </p>
* <p>Description: </p>
* <p>Copyright: Copyright (c) 2003</p>
* <p>Company: </p>
* @author not attributable
* @version 1.0
*/

public class Test {
public Test() {
Runtime ObjRunTime = Runtime.getRuntime();
byte[] env = new byte[1000];
try{
Process ObjPrcess = ObjRunTime.exec("cmd /c echo %Path%");
InputStream in = ObjPrcess.getInputStream();
in.read(env);
}catch(Exception e) { e.printStackTrace();}
System.out.println(new String(env).trim());
}
public static void main(String[] args) {
Test test = new Test();
}
}
首先,java.lang.Runtime执行WINDOWS命令.要说明"echo"并不是系统命令所以要在WIN SHELL内执行.
其次,java.lang.Process取得执行结果.
再次,转化为字符串返回.
谢谢诸君关注,来者有分.稍后结贴!

[rsldy]

不行，打印出来是 ：%Path%

[rsldy]

行了