java reads operating system environment variables
import java.util.*; import java.io.*; class SysProb { //返回当前系统变量的函数,结果放在一个Properties里边,这里只针对win2k以上的,其它系统可以自己改进 public Properties getEnv() throws Exception { Properties prop=new Properties(); String OS = System.getProperty("os.name").toLowerCase(); Process p=null; if(OS.indexOf("windows")>-1) { p=Runtime.getRuntime().exec("cmd /c set"); //其它的操作系统可以自行处理, 我这里是win2k } BufferedReader br=new BufferedReader(new InputStreamReader(p.getInputStream())); String line; while((line=br.readLine())!=null) { int i=line.indexOf("="); if(i>-1) { String key=line.substring(0,i); String value=line.substring(i+1); prop.setProperty(key,value); } } return prop; } //具体用法 public static void main(String[] args) { try { SysProb sp=new SysProb(); Properties p=sp.getEnv(); System.out.println(p.getProperty("Path")); //注意大小写,如果写成path就不对了 } catch(Exception e) { System.out.println(e); } } }
For more articles related to java reading operating system environment variables, please pay attention to the PHP Chinese website!

Java is widely used in enterprise-level applications because of its platform independence. 1) Platform independence is implemented through Java virtual machine (JVM), so that the code can run on any platform that supports Java. 2) It simplifies cross-platform deployment and development processes, providing greater flexibility and scalability. 3) However, it is necessary to pay attention to performance differences and third-party library compatibility and adopt best practices such as using pure Java code and cross-platform testing.

JavaplaysasignificantroleinIoTduetoitsplatformindependence.1)Itallowscodetobewrittenonceandrunonvariousdevices.2)Java'secosystemprovidesusefullibrariesforIoT.3)ItssecurityfeaturesenhanceIoTsystemsafety.However,developersmustaddressmemoryandstartuptim

ThesolutiontohandlefilepathsacrossWindowsandLinuxinJavaistousePaths.get()fromthejava.nio.filepackage.1)UsePaths.get()withSystem.getProperty("user.dir")andtherelativepathtoconstructthefilepath.2)ConverttheresultingPathobjecttoaFileobjectifne

Java'splatformindependenceissignificantbecauseitallowsdeveloperstowritecodeonceandrunitonanyplatformwithaJVM.This"writeonce,runanywhere"(WORA)approachoffers:1)Cross-platformcompatibility,enablingdeploymentacrossdifferentOSwithoutissues;2)Re

Java is suitable for developing cross-server web applications. 1) Java's "write once, run everywhere" philosophy makes its code run on any platform that supports JVM. 2) Java has a rich ecosystem, including tools such as Spring and Hibernate, to simplify the development process. 3) Java performs excellently in performance and security, providing efficient memory management and strong security guarantees.

JVM implements the WORA features of Java through bytecode interpretation, platform-independent APIs and dynamic class loading: 1. Bytecode is interpreted as machine code to ensure cross-platform operation; 2. Standard API abstract operating system differences; 3. Classes are loaded dynamically at runtime to ensure consistency.

The latest version of Java effectively solves platform-specific problems through JVM optimization, standard library improvements and third-party library support. 1) JVM optimization, such as Java11's ZGC improves garbage collection performance. 2) Standard library improvements, such as Java9's module system reducing platform-related problems. 3) Third-party libraries provide platform-optimized versions, such as OpenCV.

The JVM's bytecode verification process includes four key steps: 1) Check whether the class file format complies with the specifications, 2) Verify the validity and correctness of the bytecode instructions, 3) Perform data flow analysis to ensure type safety, and 4) Balancing the thoroughness and performance of verification. Through these steps, the JVM ensures that only secure, correct bytecode is executed, thereby protecting the integrity and security of the program.


Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

Dreamweaver CS6
Visual web development tools

Notepad++7.3.1
Easy-to-use and free code editor

SublimeText3 Linux new version
SublimeText3 Linux latest version

MantisBT
Mantis is an easy-to-deploy web-based defect tracking tool designed to aid in product defect tracking. It requires PHP, MySQL and a web server. Check out our demo and hosting services.

SublimeText3 Chinese version
Chinese version, very easy to use
