The function and usage instructions of System.getProperty() in Java

Table of Contents

1. System of Java

1.getProperty()

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1. System of Java

1.getProperty()

System.getProperties() can determine the current system properties, and the return value is a Properties;

System.load(String filename) is equivalent to: System.getProperties().load(String filename). Their function is to load the code file with the specified file name from the local file system as a dynamic library.
System.setProperties(Properties propes) sets system properties to Properties parameters;
System.setProperties(String key,String value) is equivalent to System.getProperties().setProperties(String key,String value): Sets the system property indicated by the specified key

Description of key-related values
java.version Java runtime environment version
java.vendor Java runtime environment vendor
java.vendor.url Java vendor URL
java.home Java installation directory
java.vm.specification.version Java virtual machine specification version
java.vm.specification.vendor Java Virtual Machine Specification Vendor
java.vm.specification.name Java virtual machine specification name
java.vm.version Java virtual machine implementation version
java.vm.vendor Java virtual machine implementation vendor
java.vm.name Java virtual machine implementation name
java.specification.version Java runtime environment specification version
java.specification.vendor Java Runtime Environment Specification Vendor
java.specification.name Java runtime environment specification name
java.class.version Java class format version number
java.class.path Java class path
java.library.path List of paths searched when loading the library
java.io.tmpdir default temporary file path
java.compiler The name of the JIT compiler to use
java.ext.dirs Path to one or more extension directories
os.name The name of the operating system
os.arch operating system architecture
os.version operating system version
file.separator file separator ("/" on UNIX systems)
path.separator path separator (":" on UNIX systems)
line.separator line separator ("/n" on UNIX systems)
user.name User’s account name
user.home User's home directory
user.dir The current working directory of the user

Java code

public class TestSystemGetSet {
    static{
        System.setProperty("DB", "mysql");//Can be used as a global variable and used anywhere
    }
    public static void main(String[] args) {
        System.out.println(System.getProperty("os.version"));
        System.out.println(System.getProperty("java.library.path"));
        System.out.println(System.getProperty("DB"));

        Properties properties = System.getProperties();
        for (Object key : properties.keySet()) {
            System.out.println("key=" + key + "\t\t\tvalue=" + properties.get(key));
        }
    }
}

Output results

10.0
C:\Program Files\Java\jdk1.8.0_202\bin;C:\Windows\Sun\Java\bin;C:\Windows\system32;C:\Windows;C :\Program Files (x86)\Common Files\Oracle\Java\javapath;C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C :\Windows\System32\WindowsPowerShell\v1.0\;C:\Windows\System32\OpenSSH\;C:\Program Files (x86)\\
VIDIA Corporation\PhysX\ Common;C:\Program Files\\
VIDIA Corporation\\
VIDIA NvDLISR;"C:\Program Files\Java\jdk1.8.0_202\bin;C:\Program Files\Java\jdk1 .8.0_202\jre\bin;";C:\Program Files\Go\bin;C:\Program Files\Go\bin;C:\Program Files\PuTTY\ ;C:\Program Files\Git\cmd;C:\Program Files\TortoiseGit\bin;C:\Program Files\Microsoft VS Code\bin;C:\Users\Administrator \AppData\Local\Microsoft\WindowsApps;C:\Users\Administrator\go\bin;C:\Program Files\JetBrains\GoLand 2023.2\bin;;C:\ Program Files\JetBrains\IntelliJ IDEA 2023.2.3\bin;;.
mysql
key=java.runtime.name value=Java(TM) SE Runtime Environment
key=sun.boot.library.path value=C:\Program Files\Java\jdk1.8.0_202\jre\bin
key=java.vm.version value=25.202-b08
key=DB value=mysql
key=java.vm.vendor value=Oracle Corporation
key=java.vendor.url value=http://java.oracle.com/
key=path.separator value=;
key=java.vm.name value=Java HotSpot(TM) 64-Bit Server VM
key=file.encoding.pkg value=sun.io
key=user.country value=CN
key=user.script value=
key=sun.java.launcher value=SUN_STANDARD
key=sun.os.patch.level value=
key=java.vm.specification.name value=Java Virtual Machine Specification
key=user.dir value=D:\WorkSpace\EclipseWorkSpace\springboot_aop
key=java.runtime.version value=1.8.0_202-b08
key=java.awt.graphicsenv value=sun.awt.Win32GraphicsEnvironment
key=java.endorsed.dirs value=C:\Program Files\Java\jdk1.8.0_202\jre\lib\endorsed
key=os.arch value=amd64
key=java.io.tmpdir value=C:\Users\ADMINI~1\AppData\Local\Temp\
key=line.separator value=

key=java.vm.specification.vendor value=Oracle Corporation
key=user.variant value=
key=os.name value=Windows 10
key=sun.jnu.encoding value=GBK
key=java.library.path value=C:\Program Files\Java\jdk1.8.0_202\bin;C:\Windows\Sun\Java\bin;C:\Windows\ system32;C:\Windows;C:\Program Files (x86)\Common Files\Oracle\Java\javapath;C:\Windows\system32;C:\Windows;C:\ Windows\System32\Wbem;C:\Windows\System32\WindowsPowerShell\v1.0\;C:\Windows\System32\OpenSSH\;C:\Program Files (x86) \\
VIDIA Corporation\PhysX\Common;C:\Program Files\\
VIDIA Corporation\\
VIDIA NvDLISR;"C:\Program Files\Java\jdk1.8.0_202\bin;C:\ \Program Files\Java\jdk1.8.0_202\jre\bin;";C:\Program Files\Go\bin;C:\Program Files\Go\bin;C: \Program Files\PuTTY\;C:\Program Files\Git\cmd;C:\Program Files\TortoiseGit\bin;C:\Program Files\Microsoft VS Code\bin ;C:\Users\Administrator\AppData\Local\Microsoft\WindowsApps;C:\Users\Administrator\go\bin;C:\Program Files\JetBrains\GoLand 2023.2 \bin;;C:\Program Files\JetBrains\IntelliJ IDEA 2023.2.3\bin;;.
key=java.specification.name value=Java Platform API Specification
key=java.class.version value=52.0
key=sun.management.compiler value=HotSpot 64-Bit Tiered Compilers
key=os.version value=10.0
key=user.home value=C:\Users\Administrator
key=user.timezone value=
key=java.awt.printerjob value=sun.awt.windows.WPrinterJob
key=file.encoding value=UTF-8
key=java.specification.version value=1.8
key=java.class.path value=C:\Program Files\Java\jdk1.8.0_202\jre\lib\charsets.jar;C:\Program Files\Java\jdk1.8.0 _202\jre\lib\deploy.jar;C:\Program Files\Java\jdk1.8.0_202\jre\lib\ext\access-bridge-64.jar;C:\ \Program Files\Java\jdk1.8.0_202\jre\lib\ext\cldrdata.jar;C:\Program Files\Java\jdk1.8.0_202\jre\lib\ ext\dnsns.jar;C:\Program Files\Java\jdk1.8.0_202\jre\lib\ext\jaccess.jar;C:\Program Files\Java\jdk1. 8.0_202\jre\lib\ext\jfxrt.jar;C:\Program Files\Java\jdk1.8.0_202\jre\lib\ext\localedata.jar;C:\ \Program Files\Java\jdk1.8.0_202\jre\lib\ext\\
ashorn.jar;C:\Program Files\Java\jdk1.8.0_202\jre\lib\ ext\sunec.jar;C:\Program Files\Java\jdk1.8.0_202\jre\lib\ext\sunjce_provider.jar;C:\Program Files\Java\jdk1. 8.0_202\jre\lib\ext\sunmscapi.jar;C:\Program Files\Java\jdk1.8.0_202\jre\lib\ext\sunpkcs11.jar;C:\ \Program Files\Java\jdk1.8.0_202\jre\lib\ext\zipfs.jar;C:\Program Files\Java\jdk1.8.0_202\jre\lib\ javaws.jar;C:\Program Files\Java\jdk1.8.0_202\jre\lib\jce.jar;C:\Program Files\Java\jdk1.8.0_202\jre\ \lib\jfr.jar;C:\Program Files\Java\jdk1.8.0_202\jre\lib\jfxswt.jar;C:\Program Files\Java\jdk1.8.0_202 \jre\lib\jsse.jar;C:\Program Files\Java\jdk1.8.0_202\jre\lib\management-agent.jar;C:\Program Files\Java \jdk1.8.0_202\jre\lib\plugin.jar;C:\Program Files\Java\jdk1.8.0_202\jre\lib\resources.jar;C:\Program Files\Java\jdk1.8.0_202\jre\lib\rt.jar;D:\WorkSpace\EclipseWorkSpace\springboot_aop\target\test-classes;D:\WorkSpace\EclipseWorkSpace \springboot_aop\target\classes;D:\.m2\repo\org\springframework\spring-context\5.1.6.RELEASE\spring-context-5.1.6.RELEASE.jar ;D:\.m2\repo\org\springframework\spring-aop\5.1.6.RELEASE\spring-aop-5.1.6.RELEASE.jar;D:\.m2\ repo\org\springframework\spring-beans\5.1.6.RELEASE\spring-beans-5.1.6.RELEASE.jar;D:\.m2\repo\org\springframework\ spring-core\5.1.6.RELEASE\spring-core-5.1.6.RELEASE.jar;D:\.m2\repo\org\springframework\spring-jcl\5.1.6. RELEASE\spring-jcl-5.1.6.RELEASE.jar;D:\.m2\repo\org\springframework\spring-expression\5.1.6.RELEASE\spring-expression-5.1. 6.RELEASE.jar;C:\Program Files\JetBrains\IntelliJ IDEA 2023.2.3\lib\idea_rt.jar
key=user.name value=Administrator
key=java.vm.specification.version value=1.8
key=sun.java.command value=com.lwz.TestSystemGetSet
key=java.home value=C:\Program Files\Java\jdk1.8.0_202\jre
key=sun.arch.data.model value=64
key=user.language value=zh
key=java.specification.vendor value=Oracle Corporation
key=awt.toolkit value=sun.awt.windows.WToolkit
key=java.vm.info value=mixed mode
key=java.version value=1.8.0_202
key=java.ext.dirs value=C:\Program Files\Java\jdk1.8.0_202\jre\lib\ext;C:\Windows\Sun\Java\lib\ ext
key=sun.boot.class.path value=C:\Program Files\Java\jdk1.8.0_202\jre\lib\resources.jar;C:\Program Files\Java\jdk1 .8.0_202\jre\lib\rt.jar;C:\Program Files\Java\jdk1.8.0_202\jre\lib\sunrsasign.jar;C:\Program Files\ Java\jdk1.8.0_202\jre\lib\jsse.jar;C:\Program Files\Java\jdk1.8.0_202\jre\lib\jce.jar;C:\ Program Files\Java\jdk1.8.0_202\jre\lib\charsets.jar;C:\Program Files\Java\jdk1.8.0_202\jre\lib\jfr.jar; C:\Program Files\Java\jdk1.8.0_202\jre\classes
key=java.vendor value=Oracle Corporation
key=file.separator value=\
key=java.vendor.url.bug value=http://bugreport.sun.com/bugreport/
key=sun.io.unicode.encoding value=UnicodeLittle
key=sun.cpu.endian value=little
key=sun.desktop value=windows
key=sun.cpu.isalist value=amd64

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