Java Provider keys()用法及代码示例

java.security.Provider类的keys()方法用于返回此哈希表中的键的枚举。

用法:

public Enumeration keys()

返回值：此方法返回此哈希表中的键的枚举。

下面是说明keys()方法的示例：

示例1:

// Java program to demonstrate 
// keys() method 
  
import java.security.*; 
import java.util.*; 
  
public class GFG1 { 
    public static void main(String[] argv) 
    { 
        // Declaring int variable 
        int i = 10; 
  
        try { 
            // creating the object of SecureRandom 
            SecureRandom sr = SecureRandom.getInstance("NativePRNGBlocking"); 
  
            // getting the Provider of the SecureRandom sr 
            // by using method getProvider() 
            Provider provider = sr.getProvider(); 
  
            // Declaring the variable of Enumeration<Object> type 
            Enumeration<Object> enume; 
  
            // getting the enumeration of the keys 
            enume = provider.keys(); 
  
            // printing the enummerated keys 
            System.out.println("enumeration of the values: \n"); 
            while (i > 0) { 
                System.out.println("Value is: " + enume.nextElement()); 
                i--; 
            } 
        } 
  
        catch (NoSuchAlgorithmException e) { 
            System.out.println("Exception thrown : " + e); 
        } 
    } 
}

输出：

enumeration of the values: 

Value is: Alg.Alias.Signature.SHA1/DSA
Value is: Alg.Alias.Signature.1.2.840.10040.4.3
Value is: Alg.Alias.Signature.DSS
Value is: SecureRandom.SHA1PRNG ImplementedIn
Value is: KeyStore.JKS
Value is: Alg.Alias.MessageDigest.SHA-1
Value is: MessageDigest.SHA
Value is: KeyStore.CaseExactJKS
Value is: CertStore.com.sun.security.IndexedCollection ImplementedIn
Value is: Signature.SHA256withDSA

示例2:

// Java program to demonstrate 
// keys() method 
  
import java.security.*; 
import java.util.*; 
  
public class GFG1 { 
    public static void main(String[] argv) 
    { 
        // Declaring int variable 
        int i = 10; 
  
        try { 
            // creating the object of Signature 
            Signature sr = Signature.getInstance("SHA1withDSA"); 
  
            // getting the Provider of the Signature sr 
            // by using method getProvider() 
            Provider provider = sr.getProvider(); 
  
            // Declaring the variable of Enumeration<Object> type 
            Enumeration<Object> enume; 
  
            // getting the enumeration of the keys 
            enume = provider.keys(); 
  
            // printing the enummerated keys 
            System.out.println("enumeration of the values: \n"); 
            while (i > 0) { 
                System.out.println("Value is: " + enume.nextElement()); 
                i--; 
            } 
        } 
  
        catch (NoSuchAlgorithmException e) { 
            System.out.println("Exception thrown : " + e); 
        } 
    } 
}

输出：

enumeration of the values: 

Value is: Alg.Alias.Signature.SHA1/DSA
Value is: Alg.Alias.Signature.1.2.840.10040.4.3
Value is: Alg.Alias.Signature.DSS
Value is: SecureRandom.SHA1PRNG ImplementedIn
Value is: KeyStore.JKS
Value is: Alg.Alias.MessageDigest.SHA-1
Value is: MessageDigest.SHA
Value is: KeyStore.CaseExactJKS
Value is: CertStore.com.sun.security.IndexedCollection ImplementedIn
Value is: Signature.SHA256withDSA

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注：本文由纯净天空筛选整理自RohitPrasad3大神的英文原创作品 Provider keys() method in Java with Examples。非经特殊声明，原始代码版权归原作者所有，本译文未经允许或授权，请勿转载或复制。