在Java中使用示例打包 isSealed(URL) 方法

Java.lang.Package 类的isSealed(URL)方法用于检查这个包是否是密封的，相对于指定的 URL。该方法将结果作为布尔值返回。
句法：

public boolean isSealed(URL url)

参数：此方法不接受任何参数。
返回值：此方法将结果作为布尔值返回。
下面的程序演示了 isSealed(URL) 方法。
示例 1：

Java

// Java program to demonstrate
// isSealed(URL) method
 
import java.net.*;
 
public class Test {
    public static void main(String[] args)
        throws MalformedURLException
    {
 
        // returns the Package
        // object for this package
        Package myPackage
            = Package.getPackage("java.lang");
 
        System.out.println(
            "Package represented by myPackage: "
            + myPackage.toString());
 
        URL url
            = new URL("https://www.geeksforgeeks.org");
 
        // check if this package is sealed or not
        // using isSealed(URL) method
        System.out.println(
            "Is this package sealed or not: "
            + myPackage.isSealed(url));
    }
}

输出：

Package represented by myPackage: package java.lang, Java Platform API Specification, version 1.8
Is this package sealed or not: false

示例 2：

Java

// Java program to demonstrate
// isSealed(URL) method
 
import java.net.*;
 
public class Test {
    public static void main(String[] args)
        throws MalformedURLException
    {
 
        // returns the Package
        // object for this package
        Package myPackage
            = Package.getPackage("java.io");
 
        System.out.println(
            "Package represented by myPackage: "
            + myPackage.toString());
 
        URL url
            = new URL("http://www.gfg.org");
 
        // check if this package is sealed or not
        // using isSealed(URL) method
        System.out.println(
            "Is this package sealed or not: "
            + myPackage.isSealed(url));
    }
}

输出：

Package represented by myPackage: package java.io, Java Platform API Specification, version 1.8
Is this package sealed or not: false

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