Java DigestOutputStream.toString()方法及示例

java.security.DigestOutputStream 类的 toString() 方法用于提供字符串格式的DigestOutputStream对象。

语法

public String toString()

返回值： 该方法以字符串格式返回 DigestOutputStream 的对象。

注意： 本文中的所有程序都不会在在线IDE上运行，因为没有’name’文件存在。你可以在你的系统中的Java编译器上检查这段代码。为了检查这段代码，在你的系统上创建一个’name’文件。

下面是说明 toString() 方法的例子。

例1 :

// Java program to demonstrate
// toString() method
  
import java.security.*;
import java.util.*;
import java.io.*;
  
public class GFG {
    public static void main(String[] argv)
    {
  
        try {
  
            // creating the object of MessageDigest
            // and getting instance
            // By using getInstance() method
            MessageDigest sr
                = MessageDigest.getInstance("MD5");
  
            // creating and initializing
            // object of OutputStream
            OutputStream is
                = new FileOutputStream(
                    "f:/java/name.txt");
  
            // creating and initializing
            // object of DigestOutputStream
            DigestOutputStream di
                = new DigestOutputStream(is, sr);
  
            // getting the string
            // representation of DigestOutputStream
            // using toString() method
            String str = di.toString();
  
            // display the result
            System.out.println("Status : " + str);
        }
  
        catch (NoSuchAlgorithmException e) {
  
            System.out.println("Exception thrown : " + e);
        }
        catch (NullPointerException e) {
  
            System.out.println("Exception thrown : " + e);
        }
        catch (FileNotFoundException e) {
  
            System.out.println("Exception thrown : " + e);
        }
    }
}

输出。

Status : [Digest Output Stream] MD5 Message Digest from SUN, 

例2 :

// Java program to demonstrate
// toString() method
  
import java.security.*;
import java.util.*;
import java.io.*;
  
public class GFG {
    public static void main(String[] argv)
    {
        try {
            // creating the object of MessageDigest
            // and getting instance
            // By using getInstance() method
            MessageDigest sr
                = MessageDigest.getInstance("SHA-1");
  
            // creating and initializing
            // object of OutputStream
            OutputStream is
                = new FileOutputStream(
                    "f:/java/name.txt");
  
            // creating and initializing
            // object of DigestOutputStream
            DigestOutputStream di
                = new DigestOutputStream(is, sr);
  
            // getting the string representation
            // of DigestOutputStream
            // using toString() method
            String str = di.toString();
  
            // display the result
            System.out.println("Status : " + str);
        }
  
        catch (NoSuchAlgorithmException e) {
  
            System.out.println("Exception thrown : " + e);
        }
        catch (NullPointerException e) {
  
            System.out.println("Exception thrown : " + e);
        }
        catch (FileNotFoundException e) {
  
            System.out.println("Exception thrown : " + e);
        }
    }
}

输出。

Status : [Digest Output Stream] SHA-1 Message Digest from SUN, 

参考资料: https://docs.oracle.com/javase/9/docs/api/java/security/DigestOutputStream.html#setMessageDigest-java.security.MessageDigest-