Java中的提供程序values()方法

可以使用使用values()类java.security.Provider中的方法获得的不可修改的Collection视图来查看Provider中的属性值。此方法不需要任何参数，并且返回属性值的不可修改的Collection视图。

演示此的程序如下所示-

示例

import java.security.*;
import java.util.*;
public class Demo {
   public static void main(String[] argv) throws Exception {
      try {
         Signature sign = Signature.getInstance("DSA");
         Provider p = sign.getProvider();
         Collection<Object> val = p.values();
         Iterator i = val.iterator();
         System.out.println("The unmodifiable Collection view is: \n");
         int x = 30;
         while (x > 0) {
            System.out.println(i.next());
            x--;
         }
      } catch (NoSuchAlgorithmException e) {
         System.out.println("Error!!! NoSuchAlgorithmException");
      }
   }
}

输出结果

The unmodifiable Collection view is:
SHA1withDSA
SHA1withDSA
SHA1withDSA
Software
sun.security.provider.JavaKeyStore$DualFormatJKS
SHA
sun.security.provider.SHA
sun.security.provider.JavaKeyStore$CaseExactJKS
Software
sun.security.provider.DSA$SHA256withDSA
SHA
SHA1withDSA
Software
Software
Software
sun.security.provider.DSA$RawDSA
X.509
java.security.interfaces.DSAPublicKey|java.security.interfaces.DSAPrivateKey
sun.security.provider.certpath.IndexedCollectionCertStore
sun.security.provider.Sun
SHA
SHA1withDSA
sun.security.provider.DomainKeyStore$DKS
Software
SHA256withDSA
SHA224withDSA
1024
1024
Software
sun.security.provider.DSAKeyFactory