Java KeyStore getCertificate()用法及代碼示例

java.security.KeyStore類的getCertificate()方法用於為所請求的別名提供證書。。

用法:

public final Certificate
  getCertificate(String alias)
  throws KeyStoreException

參數：此方法接受別名的名稱作為要獲取其證書的參數。

返回值：此方法返回所請求別名的證書(如果存在)。

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getCertificate()方法的示例：

示例1:

// Java program to demonstrate 
// getCertificate() 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 KeyStore 
            // and getting instance 
            // By usng getInstance() method 
            KeyStore sr = KeyStore.getInstance("JKS"); 
  
            // keystore password is required 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); 
  
            // getting the certificate 
            // using getCertificate() method 
            X509Certificate cert 
                = (X509Certificate)sr 
                      .getCertificate("ftpkey"); 
  
            // display the result 
            System.out.println("Certificate version : "
                               + cert.getVersion()); 
        } 
  
        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：

Certificate version : 3

示例2:對於KeyStoreException

// Java program to demonstrate 
// getCertificate() 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 KeyStore 
            // and getting instance 
            // By usng getInstance() method 
            KeyStore sr = KeyStore.getInstance("JKS"); 
  
            // intializing keystore object 
            // sr.load(is, pass); 
  
            // getting the certificate 
            // using getCertificate() method 
            X509Certificate cert 
                = (X509Certificate)sr 
                      .getCertificate("ftpkey"); 
  
            // display the result 
            System.out.println("Certificate version : "
                               + cert.getVersion()); 
        } 
        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#getCertificate-java.lang.String-

相關用法

注：本文由純淨天空篩選整理自RohitPrasad3大神的英文原創作品 KeyStore getCertificate() 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。