Java MessageDigest getDigestLength()用法及代碼示例

MessageDigest類的getDigestLength()方法用於獲取消息摘要對象的對象大小(以字節為單位)。

用法:

public final int getDigestLength()

返回值：此方法以字節形式提供消息摘要的長度。

下麵是說明getDigestLength()方法的示例：

示例1:

// Java program to demonstrate 
// getDigestLength() method 
  
import java.security.*; 
import java.util.*; 
  
public class GFG1 { 
    public static void main(String[] argv) 
    { 
        try { 
  
            // creating object of MessageDigest 
            MessageDigest msd 
                = MessageDigest.getInstance("SHA-256", "SUN"); 
  
            // getting the length of MessageDigest of object msd 
            // by using method getDigestLength() 
            int length = msd.getDigestLength(); 
  
            // printing the provider name 
            System.out.println("Message digest length : "
                               + length); 
        } 
  
        catch (NoSuchAlgorithmException e) { 
  
            System.out.println("Exception thrown : " + e); 
        } 
        catch (NoSuchProviderException e) { 
  
            System.out.println("Exception thrown : " + e); 
        } 
    } 
}

輸出：

Message digest length : 32

示例2:

// Java program to demonstrate 
// getDigestLength() method 
  
import java.security.*; 
import java.util.*; 
  
public class GFG1 { 
    public static void main(String[] argv) 
    { 
        try { 
  
            // creating object of MessageDigest 
            MessageDigest msd 
                = MessageDigest.getInstance("MD5"); 
  
            // getting the length of MessageDigest of object msd 
            // by using method getDigestLength() 
            int length = msd.getDigestLength(); 
  
            // printing the provider name 
            System.out.println("Message digest length : "
                               + length); 
        } 
  
        catch (NoSuchAlgorithmException e) { 
  
            System.out.println("Exception thrown : " + e); 
        } 
    } 
}

輸出：

Message digest length : 16

參考： https://docs.oracle.com/javase/9/docs/api/java/security/MessageDigest.html#getDigestLength–

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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 getDigestLength() 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。