Java uses the getProperty() function of the System class to obtain system properties

Java uses the getProperty() function of the System class to obtain system properties

The System class is one of the core classes of Java and provides some system-related methods. Among them, the getProperty() function is a very practical method that can be used to obtain system-related properties. This method has the following syntax:

public static String getProperty(String key)

This method accepts a string parameter key, which represents the key name of the system property to be obtained, and returns a string. Indicates the value corresponding to this attribute.

In actual development, we often use the getProperty() function to obtain some system-related information. Below, we'll demonstrate how to use this function with some sample code.

Example 1: Get the Java version

public class GetSystemProperty {
    public static void main(String[] args) {
        String javaVersion = System.getProperty("java.version");
        System.out.println("Java版本：" + javaVersion);
    }
}

Running the above code will output the current Java version information, for example:

Java version: 14.0.2

Example 2: Get the operating system type

public class GetSystemProperty {
    public static void main(String[] args) {
        String osName = System.getProperty("os.name");
        System.out.println("操作系统：" + osName);
    }
}

Run the above code, the type of the current operating system will be output, for example:

Operating system: Windows 10

Example 3 : Get the user's username

public class GetSystemProperty {
    public static void main(String[] args) {
        String userName = System.getProperty("user.name");
        System.out.println("用户名：" + userName);
    }
}

Running the above code will output the current user's username, for example:

Username: john

Example 4: Get the current job Directory

public class GetSystemProperty {
    public static void main(String[] args) {
        String currentDirectory = System.getProperty("user.dir");
        System.out.println("当前工作目录：" + currentDirectory);
    }
}

Running the above code will output the path of the current working directory, for example:

Current working directory: C:UsersjohnDocuments

Through the above example, we can see The getProperty() function of the System class can easily obtain system-related information and help us better understand and control the status of the system.

It should be noted that when using the getProperty() function, you need to pass in the corresponding property key names. These key names have certain conventions with system-related properties. Commonly used system property key names can be obtained by consulting Java documentation or search engines such as Baidu.

Summary:

The getProperty() function of the System class is a very practical method that can be used to obtain system-related properties. We can use this function to obtain information such as Java version, operating system type, user name, current working directory, etc. With this information, we can better understand and control the status of the system. I hope this article can be helpful to readers.

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