Java KeyStore containsAlias()用法及代碼示例

java.security.KeyStore類的containsAlias()方法用於檢查請求的alies的存在。

用法:

public final boolean containsAlias(String alias)
  throws KeyStoreException

參數：此方法將別名的名稱作為要檢查其條目的String類型的參數來查找。

返回值：此方法返回表明結果的布爾值。

異常：如果您不初始化此 key 庫，則此方法將引發KeyStoreException。

注意：由於不存在“ privatekey” key 庫，因此本文中的所有程序都無法在在線IDE上運行。您可以在係統上的Java編譯器上檢查此代碼。要檢查此代碼，請在係統上創建 key 庫“ privatekey”，並設置自己的 key 庫密碼以訪問該 key 庫。

下麵是說明containsAlias()方法的示例：

示例1:

// Java program to demonstrate 
// getInstance() method 
  
import java.security.*; 
import java.security.cert.*; 
import java.util.*; 
import java.io.*; 
  
public class GFG { 
    public static void main(String[] argv) 
    { 
        try { 
  
            // creating the object of MessageDigest 
            // and getting instance 
            // By usng getInstance() method 
            KeyStore sr = KeyStore.getInstance("JKS"); 
  
            // Keystore password is require 
            // to access Keystore 
            char[] pass = ("123456").toCharArray(); 
  
            // creating and intializing 
            // object of InputStream 
            InputStream is 
                = new FileInputStream( 
                    "f:/java/private key.store"); 
  
            // intializing keystore object 
            sr.load(is, pass); 
  
            // checking the presence of the aliases 
            // using containsAlias() method 
            boolean status 
                = sr.containsAlias("ftpkey"); 
  
            // display the result 
            if (status) 
                System.out.println("This aliases is present"); 
            else
                System.out.println("This aliases is absent"); 
        } 
  
        catch (NoSuchAlgorithmException e) { 
  
            System.out.println("Exception thrown : " + e); 
        } 
        catch (NullPointerException e) { 
  
            System.out.println("Exception thrown : " + e); 
        } 
        catch (KeyStoreException e) { 
  
            System.out.println("Exception thrown : " + e); 
        } 
        catch (FileNotFoundException e) { 
  
            System.out.println("Exception thrown : " + e); 
        } 
        catch (IOException e) { 
  
            System.out.println("Exception thrown : " + e); 
        } 
        catch (CertificateException e) { 
  
            System.out.println("Exception thrown : " + e); 
        } 
    } 
}

輸出：

This aliases is present

示例2:對於KeyStoreException

// Java program to demonstrate 
// getInstance() method 
  
import java.security.*; 
import java.security.cert.*; 
import java.util.*; 
import java.io.*; 
  
public class GFG { 
    public static void main(String[] argv) 
    { 
        try { 
  
            // creating the object of MessageDigest 
            // and getting instance 
            // By usng getInstance() method 
            KeyStore sr = KeyStore.getInstance("JKS"); 
  
            // intializing keystore object 
            // sr.load(is, pass); 
  
            // checking the presence of the aliases 
            // using containsAlias() method 
            boolean status = sr.containsAlias("gfg"); 
  
            // display the result 
            if (status) 
                System.out.println("This aliases is present"); 
            else
                System.out.println("This aliases is absent"); 
        } 
        catch (NullPointerException e) { 
  
            System.out.println("Exception thrown : " + e); 
        } 
        catch (KeyStoreException e) { 
  
            System.out.println("Exception thrown : " + e); 
        } 
    } 
}

輸出：

Exception thrown :
 java.security.KeyStoreException:
 Uninitialized keystore

參考： https://docs.oracle.com/javase/9/docs/api/java/security/KeyStore.html#containsAlias-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 KeyStore containsAlias() 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。