Java.io.StringBufferInputStream Java中的类

Java.io.StringBufferInputStream类有助于创建一个输入流，可以从字符串中读取字节。如果我们使用这个类，我们只能读取字符串中每个字符的低 8 位。
但是如果我们使用 ByteArrayInputStream，则没有限制只能读取字符串中每个字符的低 8 位。
此类已被 Oracle 弃用，不应再使用。

宣言：

public class StringBufferInputStream
   extends InputStream

构造函数：

• StringBufferInputStream(String str) ：创建一个字符串输入流以从指定的字符串中读取数据。

方法：

• read() : Java.io.StringBufferInputStream.read()从输入流中读取数据字节，如果到达流的末尾则返回-1。
  句法 ：

  public int read()
  Parameters : 
  -----------
  Return  :
  Returns read character as an integer ranging from range 0 to 65535.
  -1 : when end of file is reached.

• read(byte[] buffer, int offset, int maxlen) : Java.io.StringBufferInputStream.read(byte[] buffer, int offset, int maxlen))从缓冲区中从偏移位置开始读取数据字节，直到 maxlen 并返回如果到达 Stream 的末尾，则为 -1。
  句法 ：

  public int read(byte[] buffer, int offset, int maxlen))
  Parameters : 
  buffer : destination buffer to be read into  
  offset : starting position from where to store characters
  maxlen : maximum no. of characters to be read
  Return  :
  Returns all the characters read
  -1 : when end of file is reached.

• reset() : Java.io.StringBufferInputStream.reset()重置输入流并从输入流中存在的“缓冲区”的第一个字符开始读取。
  句法 ：

  public void reset()
  Parameters : 
  -----------
  Return  :
  void
  

• skip(long b) : Java.io.StringBufferInputStream.skip(long b)跳过“b”个字节。如果到达文件末尾，则跳过几个字节。
  句法 ：

  public long skip(long b)
  Parameters : 
  b : no. of bytes to be skipped
  Return  :
  no. of bytes skipped
  

• available() : Java.io.StringBufferInputStream.available()告诉总数。可供读取的字节数。
  句法 ：

  public int available()
  Parameters : 
  ----------------
  Return  :
  total no. of bytes that can be read
  

// Java program illustrating the working of StringBufferInputStream class methods
// read(), skip(), available(), reset()
// read(char[] char_array, int offset, int maxlen)
  
import java.io.*;
public class NewClass
{
    public static void main(String[] args) throws IOException
    {
  
        String str1 = "Hello Geeks";
        String str2 = "GeeksForGeeks";
        StringBufferInputStream Geek_buffer1 = new StringBufferInputStream(str1);
        StringBufferInputStream Geek_buffer2 = new StringBufferInputStream(str2);
  
        // USe of available() : to count total bytes to be read
        System.out.println("Use of available() 1 : "+ Geek_buffer1.available());
  
        int a = 0;
        System.out.print("Use of read() method : ");
          
        // Use of read() method : reading each byte one by one
        while((a = Geek_buffer1.read()) != -1)
        {
            // Converting byte to char
            char c1 = (char)a;
            System.out.println(c1);
  
            // Use of skip() method
            long char_no = Geek_buffer1.skip(1);
            System.out.println("Characters Skipped : "+ (c1+1));
  
        }
        System.out.println("");
  
        // USe of available() : to count total bytes to be read
        System.out.println("Use of available() 2 : "+ Geek_buffer2.available());
  
          
        byte[] buffer = new byte[15];
      
        // Use of read(char[] char_array, int offset, int maxlen):
        // reading a part of array
        Geek_buffer2.read(buffer, 1, 2);
        int b = 0;
  
        System.out.print("read(char[] char_array, int offset, int maxlen): ");
        while((b = Geek_buffer2.read()) != -1)
        {
            char c2 = (char)b;
            System.out.print(c2);
        }
        System.out.println("");
  
        // Use of reset() : to reset str1 for reading again
        Geek_buffer1.reset();
        int i = 0;
        System.out.print("\nUse of read() method again after reset() : ");
          
        // Use of read() method : reading each character one by one
        while((i = Geek_buffer1.read()) != -1)
        {
            char c3 = (char)i;
            System.out.print(c3);
        }
    }
}

输出 ：

Use of available() 1 : 11
Use of read() method : H
Characters Skipped : 73
l
Characters Skipped : 109
o
Characters Skipped : 112
G
Characters Skipped : 72
e
Characters Skipped : 102
s
Characters Skipped : 116

Use of available() 2 : 13
Use of read(char[] char_array, int offset, int maxlen) method : eksForGeeks

Use of read() method again after reset() : Hello Geeks