用示例在Java中打包 getSpecificationVersion() 方法

Java.lang.Package 类的getSpecificationVersion()方法用于获取该包的规范版本。该方法将包的规范版本作为字符串返回。
句法：

public String getSpecificationVersion()

参数：此方法不接受任何参数。
返回值：此方法将包的规范版本作为字符串返回（如果已知）。否则返回 null
下面的程序演示了 getSpecificationVersion() 方法。
示例 1：

Java

// Java program to demonstrate
// getSpecificationVersion() method
 
public class Test {
    public static void main(String[] args)
    {
 
        // returns the Package object
        // for this package
        Package myPackage
            = Package.getPackage("java.lang");
 
        System.out.println(
            "Package represented by myPackage: "
            + myPackage.toString());
 
        // Get the specification version of myPackage
        // using getSpecificationVersion() method
        System.out.println(
            "Specification version of myPackage: "
            + myPackage.getSpecificationVersion());
    }
}

输出：

Package represented by myPackage: package java.lang, Java Platform API Specification, version 1.8
Specification version of myPackage: 1.8

示例 2：

Java

// Java program to demonstrate
// getSpecificationVersion() method
 
public class Test {
    public static void main(String[] args)
    {
 
        // returns the Package object
        // for this package
        Package myPackage
            = Package.getPackage("java.io");
 
        System.out.println(
            "Package represented by myPackage: "
            + myPackage.toString());
 
        // Get the name of myPackage
        // using getSpecificationVersion() method
        System.out.println(
            "Specification version of myPackage: "
            + myPackage.getSpecificationVersion());
    }
}

输出：

Package represented by myPackage: package java.io, Java Platform API Specification, version 1.8
Specification version of myPackage: 1.8

参考： https://docs.oracle.com/javase/9/docs/api/ Java/lang/Package.html#getSpecificationVersion–