Java Provider.Service getAttribute()用法及代碼示例

java.security.Provider.Service類的getAttribute()方法用於返回此方法中傳遞的特定屬性名稱的屬性值。

用法:

public final String getAttribute(String name)

返回值：此方法返回特定屬性類型的值。

下麵是說明getAttribute()方法的示例：

範例1：

// Java program to demonstrate 
// getAttribute() method 
  
import java.security.*; 
import java.util.*; 
  
public class GFG1 { 
    public static void main(String[] argv) 
    { 
        try { 
  
            // creating the object of Signature 
            Signature sr 
                = Signature.getInstance( 
                    "SHA1withDSA", "SUN"); 
  
            // getting the Provider of the Signature sr 
            // by using method getProvider() 
            Provider provider = sr.getProvider(); 
  
            // getting the service of the provider 
            // using getServices() method 
            Provider.Service service 
                = provider 
                      .getService("Signature", 
                                  sr.getAlgorithm()); 
  
            // getting algoritm of Provider.Service object 
            // by using getAlgorithm() method 
            String algo = service.getAttribute("KeySize"); 
  
            // display the result 
            System.out.println("KeySize is:" + algo); 
        } 
  
        catch (NoSuchAlgorithmException e) { 
            System.out.println("Exception thrown:" + e); 
        } 
        catch (NoSuchProviderException e) { 
            System.out.println("Exception thrown:" + e); 
        } 
    } 
}

輸出：

KeySize is:1024

範例2：

// Java program to demonstrate 
// getAttribute() method 
  
import java.security.*; 
import java.util.*; 
  
public class GFG1 { 
    public static void main(String[] argv) 
    { 
        try { 
  
            // creating object of MessageDigest 
            MessageDigest msd 
                = MessageDigest.getInstance("MD5"); 
  
            // getting the Provider of the Signature sr 
            // by using method getProvider() 
            Provider provider = msd.getProvider(); 
  
            // getting the service of the provider 
            // using getServices() method 
            Provider.Service service 
                = provider 
                      .getService("MessageDigest", 
                                  msd.getAlgorithm()); 
  
            // getting algoritm of Provider.Service object 
            // by using getAlgorithm() method 
            String algo 
                = service.getAttribute("ImplementedIn"); 
  
            // display the result 
            System.out.println("ImplementedIn:"
                               + algo); 
        } 
  
        catch (NoSuchAlgorithmException e) { 
            System.out.println("Exception thrown:"
                               + e); 
        } 
    } 
}

輸出：

ImplementedIn:Software

參考： https://docs.oracle.com/javase/9/docs/api/java/security/Provider.Service.html#getAttribute-java.lang.String-

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注：本文由純淨天空篩選整理自RohitPrasad3大神的英文原創作品 Provider.Service getAttribute() 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。