Java中的 Provider.Service toString() 方法及示例

Java.security.Provider.Service类的toString()方法返回此提供者服务的字符串表示形式。

句法：

public String toString()

返回值：此方法提供此提供程序服务的字符串表示。

下面是说明toString()方法的示例：

示例 1：

// Java program to demonstrate
// toString() 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 string representation
            // of Provider.Service object
            // by using getClassName() method
            String value = service.toString();
  
            // display the result
            System.out.println("String representation : "
                               + value);
        }
  
        catch (NoSuchAlgorithmException e) {
            System.out.println("Exception thrown : " + e);
        }
        catch (NoSuchProviderException e) {
            System.out.println("Exception thrown : " + e);
        }
    }
}

输出：

String representation : SUN: Signature.SHA1withDSA -> sun.security.provider.DSA$SHA1withDSA
aliases: [DSA, DSS, SHA/DSA, SHA-1/DSA, SHA1/DSA, SHAwithDSA, DSAWithSHA1, OID.1.2.840.10040.4.3, 1.2.840.10040.4.3, 1.3.14.3.2.13, 1.3.14.3.2.27]
attributes: {ImplementedIn=Software, KeySize=1024, SupportedKeyClasses=java.security.interfaces.DSAPublicKey|java.security.interfaces.DSAPrivateKey}

示例 2：

// Java program to demonstrate
// toString() 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 a string representation
            // of Provider.Service object
            // by using getClassName() method
            String value = service.toString();
  
            // display the result
            System.out.println("String representation : "
                               + value);
        }
  
        catch (NoSuchAlgorithmException e) {
            System.out.println("Exception thrown : " + e);
        }
    }
}

输出：

String representation : SUN: MessageDigest.MD5 -> sun.security.provider.MD5
attributes: {ImplementedIn=Software}

参考： https://docs.oracle.com/javase/9/docs/api/ Java/security/Provider.Service.html#toString–