CharArrayReader 用示例读取 Java 中的(char[]，int，int)方法

原文:https://www . geeksforgeeks . org/chararrayreader-readchar-int-int-method-in-Java-with-examples/

Java 中 CharArrayReader 类的 read(char[]，int，int) 方法用于将指定长度的字符读入到指定偏移量的数组中。这个方法阻塞流直到:

  • It takes some input from the stream.
  • Some IOException occurred.
  • It has reached the end of the stream when reading.

语法:

公共 int read(char[] charArray，int offset，int length)

参数:该方法接受三个强制参数:

  • 字符数组是要写入流中的字符数组。
  • 偏移量是数组中字符写入的偏移量索引。
  • 长度是数组中要写入的字符数。

返回值:该方法返回一个整数值，即从流中读取的字符数。如果未读取任何字符，则返回-1。

异常:如果输入输出时出现错误，该方法抛出以下异常:

  • Exception: .
  • Index out of bounds exception: If the offset value is not in the character array

的范围内

下面的方法说明了 read(char[]，int，int)方法的工作原理:

程序 1:

// Java program to demonstrate
// CharArrayReader read(char[], int, int) method

import java.io.*;
import java.util.*;

class GFG {
    public static void main(String[] args)
    {

        try {

            char[] str = { 'G', 'e', 'e', 'k', 's',
                           'F', 'o', 'r',
                           'G', 'e', 'e', 'k', 's' };

            // Create a CharArrayReader instance
            CharArrayReader reader
                = new CharArrayReader(str);

            // Get the character array
            // to be read from the stream
            char[] charArray = new char[5];

            // Get the offset index
            int offset = 0;

            // Get the length
            int length = 5;

            // Read the charArray
            // to this reader using read() method
            // This will put the str in the stream
            // till it is read by the reader
            reader.read(charArray, offset, length);

            // Print the read charArray
            System.out.println(
                Arrays.toString(charArray));

            reader.close();
        }
        catch (Exception e) {
            System.out.println(e);
        }
    }
}

输出:

[G, e, e, k, s]

程序二:

// Java program to demonstrate
// CharArrayReader read(char[], int, int) method

import java.io.*;
import java.util.*;

class GFG {
    public static void main(String[] args)
    {

        try {

            char[] str = { 'G', 'e', 'e', 'k', 's',
                           'F', 'o', 'r',
                           'G', 'e', 'e', 'k', 's' };

            // Create a CharArrayReader instance
            CharArrayReader reader
                = new CharArrayReader(str);

            // Get the character array
            // to be read from the stream
            char[] charArray
                = new char[13];

            // Get the offset index
            int offset = 0;

            // Get the length
            int length = 13;

            // Read the charArray
            // to this reader using read() method
            // This will put the str in the stream
            // till it is read by the reader
            reader.read(charArray, offset, length);

            // Print the read charArray
            System.out.println(
                Arrays.toString(charArray));

            reader.close();
        }
        catch (Exception e) {
            System.out.println(e);
        }
    }
}

输出:

[G, e, e, k, s, F, o, r, G, e, e, k, s]

参考:<A href = " https://docs . Oracle . com/javase/9/docs/API/Java/io/chararrayreader . html # read-char:A-int-int-" https://docs . Oracle . com/javase/9/docs/API/Java/io/chararrayreader . html # read-char:A-int-int-

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