Java Bytes类

Bytes 是原始类型字节的一个实用类。它提供了与字节基元有关的 静态实用方法 ，这些 方法 在Byte或Arrays中都没有找到，并且将字节解释为有符号或无符号。具体将字节视为有符号或无符号的方法见于 SignedBytes 和 UnsignedBytes。

声明 :

@GwtCompatible(emulated=true)
public final class Bytes
extends Object

下表显示了Guava Bytes类所提供的方法。

异常。

• ensureCapacity : 如果minLength或padding为负数，则出现IllegalArgumentException。
• toArray： 如果集合或其任何元素为空，则出现NullPointerException。

下面给出了一些例子，显示了Guava Bytes类方法的实现：

例1 :

// Java code to show implementation
// of Guava Bytes.asList() method
  
import com.google.common.primitives.Bytes;
import java.util.*;
  
class GFG {
    // Driver method
    public static void main(String[] args)
    {
        byte arr[] = { 3, 4, 5, 6, 7 };
  
        // Using Bytes.asList() method which convert
        // array of primitives to array of objects
        List<Byte> myList = Bytes.asList(arr);
  
        // Displaying the elements
        System.out.println(myList);
    }
}

输出:

[3, 4, 5, 6, 7]

例2 :

// Java code to show implementation
// of Guava Bytes.indexOf() method
  
import com.google.common.primitives.Bytes;
import java.util.*;
  
class GFG {
    // Driver method
    public static void main(String[] args)
    {
        byte[] arr = { 3, 4, 5, 6, 7 };
  
        // Displaying the index for
        // first occurrence of given target
        System.out.println(Bytes.indexOf(arr, (byte)5));
    }
}

输出:

2

例3 :

// Java code to show implementation
// of Guava Bytes.concat() method
  
import com.google.common.primitives.Bytes;
import java.util.*;
  
class GFG {
    // Driver method
    public static void main(String[] args)
    {
        byte[] arr1 = { 3, 4, 5 };
        byte[] arr2 = { 6, 7 };
  
        // Using Bytes.concat() method which
        // combines arrays from specified
        // arrays into a single array
        byte[] arr = Bytes.concat(arr1, arr2);
  
        // Displaying the elements
        System.out.println(Arrays.toString(arr));
    }
}

输出:

[3, 4, 5, 6, 7]

例4 :

// Java code to show implementation
// of Guava Bytes.contains() method
  
import com.google.common.primitives.Bytes;
  
class GFG {
    // Driver method
    public static void main(String[] args)
    {
        byte[] arr = { 3, 4, 5, 6, 7 };
  
        // Using Bytes.contains() method which
        // checks if element is present in array
        // or not
        System.out.println(Bytes.contains(arr, (byte)8));
        System.out.println(Bytes.contains(arr, (byte)7));
    }
}

产出 :

false
true

例5 :

// Java code to show implementation
// of Guava Bytes.lastIndexOf() method
  
import com.google.common.primitives.Bytes;
  
class GFG {
    // Driver method
    public static void main(String[] args)
    {
        byte[] arr = { 3, 4, 5, 6, 7, 5, 5 };
  
        // Using Bytes.lastIndexOf() method
        // to get last occurrence of given target
        System.out.println(Bytes.lastIndexOf(arr, (byte)5));
    }
}

输出:

6

例6 :

// Java code to show implementation
// of Guava Bytes.lastIndexOf() method
  
import com.google.common.primitives.Bytes;
  
class GFG {
    // Driver method
    public static void main(String[] args)
    {
        byte[] arr = { 3, 4, 5, 6, 7, 5, 5 };
  
        // Using Bytes.lastIndexOf() method
        // to get last occurrence of given target
        // here target i.e, 9 is not present in
        // array arr, so -1 will be returned
        System.out.println(Bytes.lastIndexOf(arr, (byte)9));
    }
}

输出:

-1