Java Package isSealed(URL)用法及代碼示例

java.lang.Package類的isSealed(URL)方法用於檢查此程序包是否相對於指定的URL是密封的。該方法以布爾值返回結果。

用法:

public boolean isSealed(URL url)

參數：此方法不接受任何參數。

返回值：此方法將結果作為布爾值返回。

下麵的程序演示了isSealed(URL)方法。

範例1：

// 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("http://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)); 
    } 
}

輸出：

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

範例2：

// 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)); 
    } 
}

輸出：

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

參考： https://docs.oracle.com/javase/9/docs/api/java/lang/Package.html#isSealed-

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注：本文由純淨天空篩選整理自guptayashgupta53大神的英文原創作品 Package isSealed(URL) method in Java with Examples。非經特殊聲明，原始代碼版權歸原作者所有，本譯文未經允許或授權，請勿轉載或複製。