Java中的提供程序keySet()方法
可以使用keySet()类java.security.Provider中的方法使用不可修改的Set视图来查看提供程序中的属性键。此方法不需要任何参数，并且根据需要返回属性键的不可修改的Set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();
Set<Object> set = p.keySet();
Iterator i= set.iterator();
System.out.println("The unmodifiable Set view is as follows:\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 Set view is as follows: Alg.Alias.Signature.SHA1/DSA Alg.Alias.Signature.1.2.840.10040.4.3 Alg.Alias.Signature.DSS SecureRandom.SHA1PRNG ImplementedIn KeyStore.JKS Alg.Alias.MessageDigest.SHA-1 MessageDigest.SHA KeyStore.CaseExactJKS CertStore.com.sun.security.IndexedCollection ImplementedIn Signature.SHA256withDSA Alg.Alias.MessageDigest.OID.1.3.14.3.2.26 Alg.Alias.Signature.DSA KeyFactory.DSA ImplementedIn KeyStore.JKS ImplementedIn AlgorithmParameters.DSA ImplementedIn Signature.NONEwithDSA Alg.Alias.CertificateFactory.X509 Signature.SHA256withDSA SupportedKeyClasses CertStore.com.sun.security.IndexedCollection Provider.id className Alg.Alias.MessageDigest.1.3.14.3.2.26 Alg.Alias.Signature.SHA-1/DSA KeyStore.DKS CertificateFactory.X.509 ImplementedIn Alg.Alias.Signature.OID.2.16.840.1.101.3.4.3.2 Alg.Alias.Signature.OID.2.16.840.1.101.3.4.3.1 Signature.SHA1withDSA KeySize Signature.NONEwithDSA KeySize CertPathValidator.PKIX ImplementedIn KeyFactory.DSA