java Java 中的 KeyStore isKeyEntry()方法，示例

Java 中的 KeyStore isKeyEntry()方法，示例

原文:https://www . geesforgeks . org/keystore-iskey entry-method-in-Java-with-examples/

java.security.KeyStore 类的 isKeyEntry() 方法用于检查特定的指定密钥条目是否存在。它返回一个布尔值，表示相同的内容。

语法:

public final boolean isKeyEntry(String alias) 
    throws KeyStoreException

参数:该方法接受别名的名称作为要检查其关键字条目的参数。

返回值:该方法返回一个布尔值，说明请求的密钥条目的存在。

异常:如果不初始化这个密钥库，这个方法抛出密钥库异常。

注意:本文中的所有程序都不会在联机 IDE 上运行，因为不存在“privatekey”密钥库。您可以在系统的 Java 编译器上检查这些代码。要检查此代码，请在您的系统上创建一个密钥库“privatekey”，并设置您自己的密钥库密码来访问该密钥库。

以下是说明iscertifientry()方法的示例:

例 1:

Java 语言(一种计算机语言，尤用于创建网站)

// Java program to demonstrate isKeyEntry() 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 using getInstance() method
            KeyStore sr = KeyStore.getInstance("JKS");

            // keystore password is required to access keystore
            char[] pass = ("123456").toCharArray();

            // creating and initializing object of InputStream
            InputStream is
                = new FileInputStream(
                    "f:/java/private key.store");

            // initializing keystore object
            sr.load(is, pass);

            // checking the presence of key entry
            // using isCertificateEntry() method
            Boolean status
                = sr.isKeyEntry("ftpkey");

            // display the result
            if (status)
                System.out.println("\nkey entry is present");
            else
                System.out.println("\nkey entry is not present");
        }

        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:

示例 2: 适用于密钥库异常

Java 语言(一种计算机语言，尤用于创建网站)

// Java program to demonstrate isKeyEntry() 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 using getInstance() method
            KeyStore sr = KeyStore.getInstance("JKS");

            // keystore password is required to access keystore
            char[] pass = ("123456").toCharArray();

            // creating and initializing object of InputStream
            InputStream is
                = new FileInputStream(
                    "f:/java/private key.store");

            // initializing keystore object
            // sr.load(is, pass);

            // checking the presence of key entry
            // using isCertificateEntry() method
            Boolean status
                = sr.isKeyEntry("ftpkey");

            // display the result
            if (status)
                System.out.println("key entry is present");
            else
                System.out.println("key entry is not present");
        }
        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);
        }
    }
}