Java MessageDigest isEqual()用法及代碼示例

java.security.MessageDigest類的isEqual()方法用於測試兩個消息摘要是否相等。

用法:

public static boolean
  isEqual(byte[] digesta, byte[] digestb)

參數：此方法需要2個字節的數組進行比較。

返回值：此方法提供布爾值，如果兩個摘要相等，則為true，否則為false。

下麵是說明isEqual()方法的示例：

示例1:對於相等的摘要值

// Java program to demonstrate 
// isEqual() method 
  
import java.security.*; 
import java.util.*; 
  
public class GFG1 { 
    public static void main(String[] argv) 
    { 
        try { 
  
            // creating object of MessageDigest 
            MessageDigest msd1 
                = MessageDigest.getInstance("SHA-256"); 
  
            // creating object of MessageDigest 
            MessageDigest msd2 
                = MessageDigest.getInstance("SHA-256"); 
  
            // getting provider used in object msd 
            // using getAlgorithm() method 
            boolean status 
                = MessageDigest 
                      .isEqual(msd1.digest(), 
                               msd2.digest()); 
  
            // check the condition 
            if (status) 
                System.out.println("msd1 is equals to msd2"); 
            else
                System.out.println("msd1 is not equals to msd2"); 
        } 
  
        catch (NoSuchAlgorithmException e) { 
  
            System.out.println("Exception thrown : " + e); 
        } 
        catch (ProviderException e) { 
  
            System.out.println("Exception thrown : " + e); 
        } 
    } 
}

輸出：

msd1 is equals to msd2

示例2:對於不相等的摘要值

// Java program to demonstrate 
// isEqual() method 
  
import java.security.*; 
import java.util.*; 
  
public class GFG1 { 
    public static void main(String[] argv) 
    { 
        try { 
  
            // creating object of MessageDigest 
            MessageDigest msd1 
                = MessageDigest.getInstance("MD5"); 
  
            // creating object of MessageDigest 
            MessageDigest msd2 
                = MessageDigest.getInstance("SHA-256"); 
  
            // getting provider used in object msd 
            // using getAlgorithm() method 
            boolean status 
                = MessageDigest.isEqual(msd1.digest(), 
                                        msd2.digest()); 
  
            // check the condition 
            if (status) 
                System.out.println("msd1 is equals to msd2"); 
            else
                System.out.println("msd1 is not equals to msd2"); 
        } 
  
        catch (NoSuchAlgorithmException e) { 
  
            System.out.println("Exception thrown : " + e); 
        } 
        catch (ProviderException e) { 
  
            System.out.println("Exception thrown : " + e); 
        } 
    } 
}

輸出：

msd1 is not equals to msd2

參考： https://docs.oracle.com/javase/9/docs/api/java/security/MessageDigest.html#isEqual-byte:A-byte:A-

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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 MessageDigest isEqual() 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。