Java中的 DigestInputStream.toString() 方法及示例

Java.security.DigestInputStream类的toString()方法提供了字符串格式的 DigestInputStream 对象。
句法：

public String toString()

返回值：该方法以字符串形式返回 DigestInputStream 的对象。
注意：本文中的所有程序都不会在在线 IDE 上运行，因为不存在“名称”文件。您可以在系统上的Java编译器上检查此代码。要检查此代码，请在您的系统上创建一个文件“名称”。
下面是说明toString()方法的示例：
示例 1：

Java

// 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 InputStream
            InputStream is
                = new FileInputStream("f:/java/name.txt");
 
            // creating and initializing
            // object of DigestInputStream
            DigestInputStream di
                = new DigestInputStream(is, sr);
 
            // getting the string representation
            // of DigestInputStream
            // 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 Input Stream] MD5 Message Digest from SUN, 

示例 2：

Java

// 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 InputStream
            InputStream is
                = new FileInputStream("f:/java/name.txt");
 
            // creating and initializing
            // object of DigestInputStream
            DigestInputStream di
                = new DigestInputStream(is, sr);
 
            // getting the string
            // representation of DigestInputStream
            // 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 Input Stream] SHA-1 Message Digest from SUN, 

参考： https://docs.oracle.com/javase/9/docs/api/ Java/security/DigestInputStream.html#toString–