Java KeyStore getCertificate()用法及代码示例

java.security.KeyStore类的getCertificate()方法用于为所请求的别名提供证书。。

用法:

public final Certificate
  getCertificate(String alias)
  throws KeyStoreException

参数：此方法接受别名的名称作为要获取其证书的参数。

返回值：此方法返回所请求别名的证书(如果存在)。

异常：如果您不初始化此 key 库，则此方法将引发KeyStoreException。

注意：由于不存在“ privatekey” key 库，因此本文中的所有程序都无法在在线IDE上运行。您可以在系统上的Java编译器上检查此代码。要检查此代码，请在系统上创建 key 库“ privatekey”，并设置自己的 key 库密码以访问该 key 库。

下面是说明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); 
        } 
    } 
}

输出：

Certificate version : 3

示例2:对于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); 
        } 
    } 
}

输出：

Exception thrown :
 java.security.KeyStoreException:
 Uninitialized keystore

参考： https://docs.oracle.com/javase/9/docs/api/java/security/KeyStore.html#getCertificate-java.lang.String-

相关用法

注：本文由纯净天空筛选整理自RohitPrasad3大神的英文原创作品 KeyStore getCertificate() method in Java with Examples。非经特殊声明，原始代码版权归原作者所有，本译文未经允许或授权，请勿转载或复制。