Java Java.io.ByteArrayInputStream用法及代码示例

java.io 包的 ByteArrayInputStream 类包含所有缓冲区，其中包含要从输入流读取的字节。 ByteArrayInputStream类方法不存在IO异常。即使关闭 Stream 后也可以调用该类的方法，对类方法没有影响。类视图如下：

--> java.io Package
    --> ByteArrayInputStream Class

用法:

public class ByteArrayInputStream
extends InputStream

有一些特定的字段：

受保护的字节[] buf：由流的创建者提供的字节数组。
受保护的int计数：索引一大于输入流缓冲区中的最后一个有效字符。
受保护的int标记：流中当前标记的位置。
受保护的int位置：这是要从输入流缓冲区读取的下一个字符的索引。

Constructor of ByteArrayInputStream Class

构造函数	执行的操作
ByteArrayInputStream(字节[]缓冲区)	它创建ByteArrayInputStream以使用缓冲区数组-“buffer”。
ByteArrayInputStream(byte[] buf, int 偏移量, int 长度)	它创建使用“buffer”的某些部分的ByteArrayInputStream，即缓冲区数组

Methods of ByteArrayInputStream class

方法	执行的操作
available()	它告诉要从输入流读取的字节总数。
close()	它关闭输入流并释放系统资源。
mark()	它标记输入流的当前位置，这意味着设置读取限制。
markSupported()	它测试该输入流是否支持标记和重置方法。
read()	它从输入流中读取下一个数据字节。
reset()	它将输入流重新定位到标记位置，称为mark()方法
skip()	跳过输入流中的“args”。

执行：

Java


// Java Program to Demonstrate ByteArrayInputStream Class
// Via mark(), read(), skip(), available(),
// markSupported(), close(), reset() Method
// Importing required classes
import java.io.*;
// Main class
public class GFG {
    // Main driver method
    public static void main(String[] args) throws Exception
    {
        // Declaring and initializing byte array
        byte[] buffer = { 71, 69, 69, 75, 83 };
        ByteArrayInputStream geek = null;
        // Try block to check for exceptions
        try {
            geek = new ByteArrayInputStream(buffer);
            // Telling the no. of bytes to be read
            // using available() method
            int number = geek.available();
            System.out.println(
                "Use of available() method : " + number);
            // Reading and printing Characters one by one
            // using read() method
            System.out.println("\nChar : "
                               + (char)geek.read());
            System.out.println("Char : "
                               + (char)geek.read());
            System.out.println("Char : "
                               + (char)geek.read());
            // Usage of mark() method
            geek.mark(0);
            // Skipping 'k' from "GEEKS"
            // using skip() method
            geek.skip(1);
            System.out.println(
                "skip() method comes to play");
            System.out.println(
                "mark() method comes to play");
            System.out.println("Char : "
                               + (char)geek.read());
            // Usage of markSupported() method
            boolean check = geek.markSupported();
            System.out.println("\nmarkSupported() : "
                               + check);
            if (geek.markSupported()) {
                // Repositioning the stream to marked
                // positions using reset() method
                geek.reset();
                System.out.println("\nreset() invoked");
                System.out.println("Char : "
                                   + (char)geek.read());
                System.out.println("Char : "
                                   + (char)geek.read());
            }
            else {
                System.out.println(
                    "reset() method not supported.");
            }
            System.out.println(
                "geek.markSupported() supported reset() : "
                + check);
        }
        // Catch block to handle the exceptions
        catch (Exception except) {
            // Displaying the exception along with line
            // number using printStackTrace() method
            except.printStackTrace();
        }
        // finally block that execute for sure
        finally {
            // Releasing the resources back to GC when
            // closes
            if (geek != null) {
                // Closing the file and releasing resources
                // using close() method
                geek.close();
            }
        }
    }
}

输出

Use of available() method : 5

Char : G
Char : E
Char : E
skip() method comes to play
mark() method comes to play
Char : S

markSupported() : true

reset() invoked
Char : K
Char : S
geek.markSupported() supported reset() : true

相关用法

注：本文由纯净天空筛选整理自佚名大神的英文原创作品 Java.io.ByteArrayInputStream class in Java。非经特殊声明，原始代码版权归原作者所有，本译文未经允许或授权，请勿转载或复制。