JAVA伊奥。Java中的SequenceInputStream-yiteyi-C++库

SequenceInputStream类允许连接多个InputStreams。它逐个读取流的数据。它从输入流的有序集合开始，从第一个流开始读取，直到到达文件末尾，然后从第二个流开始读取，依此类推，直到最后一个包含的输入流到达文件末尾。

null

构造函数和描述

SequenceInputStream（枚举e）： 初始化新创建的SequenceInputStream，它必须是生成类型为InputStream的对象的枚举。
SequenceInputStream（InputStream s1，InputStream s2）： 通过记住两个参数来初始化新创建的SequenceInputStream，这两个参数将按顺序读取，首先是s1，然后是s2。

重要方法：

阅读： 从这个输入流中读取下一个字节的数据。

Syntax:
public int read()
         throws IOException 
Returns: the next byte of data, or -1 if the end of the stream is reached.
Throws: IOException - if an I/O error occurs.

读取（字节[]b，整数关闭，整数长度）： 从这个输入流中读取多达len字节的数据到

Syntax:
public int read(byte[] b,
       int off,
       int len)
         throws IOException
Overrides: read in class InputStream
Parameters:
b - the buffer into which the data is read.
off - the start offset in array b at which the data is written.
len - the maximum number of bytes read.
Returns: int the number of bytes read.
Throws:
NullPointerException - If b is null.
IndexOutOfBoundsException - If off is negative, len is negative, 
or len is greater than b.length - off
IOException - if an I/O error occurs.

可供选择： 返回可从当前基础输入流读取（或跳过）的字节数的估计值，而无需在下次调用当前基础输入流的方法时阻塞。

Syntax :
public int available()
              throws IOException 
Overrides: available in class InputStream
Returns:an estimate of the number of bytes that can be read (or skipped over) 
from the current underlying input stream without blocking or 0 if this input stream
has been closed by invoking its close() method
Throws:
IOException - if an I/O error occurs.

关闭： 关闭此输入流并释放与该流关联的所有系统资源。

Syntax :
public void close()
           throws IOException
Overrides: close in class InputStream
Throws:
IOException - if an I/O error occurs.

下面是SequenceInputStream类的一个示例，它实现了一些重要的方法。 节目：

                     //Java program to demonstrate SequenceInputStream                   
                     import                               java.io.*;                   
                     import                               java.util.*;                   
                             
                     class                               SequenceISDemp                   
                     {                   
                                         public                               static                               void                               main(String args[])                               throws                               IOException                   
                                         {                   
                             
                                         //creating the FileInputStream objects for all the following files                   
                                         FileInputStream fin=                               new                               FileInputStream(                               "file1.txt"                               );                   
                                         FileInputStream fin2=                               new                               FileInputStream(                               "file2.txt"                               );                   
                                         FileInputStream fin3=                               new                               FileInputStream(                               "file3.txt"                               );                   
                             
                                         //adding fileinputstream obj to a vector object                   
                                         Vector v =                               new                               Vector();                   
                             
                                         v.add(fin);                   
                                         v.add(fin2);                   
                                         v.add(fin3);                   
                             
                                         //creating enumeration object by calling the elements method                   
                                         Enumeration enumeration = v.elements();                   
                             
                                         //passing the enumeration object in the constructor                   
                                         SequenceInputStream sin =                               new                               SequenceInputStream(enumeration);                   
                             
                                         // determine how many bytes are available in the first stream                   
                                         System.out.println(                               ""                               + sin.available());                   
                             
                                         // Estimating the number of bytes that can be read                   
                                         // from the current underlying input stream                   
                                         System.out.println( sin.available());                   
                             
                                         int                               i =                               0                               ;                   
                                         while                               ((i = sin.read())! = -                               1                               )                   
                                         {                   
                                         System.out.print((                               char                               )i);                   
                                         }                   
                                         sin.close();                   
                                         fin.close();                   
                                         fin2.close();                   
                                         fin3.close();                   
                                         }                   
                     }                   

输出：

19
This is first file This is second file This is third file

注意：此程序不会在联机IDE上运行，因为没有与之关联的文件。

本文由 尼森特·夏尔马 .如果你喜欢GeekSforgek，并想贡献自己的力量，你也可以使用贡献极客。组织或者把你的文章寄到contribute@geeksforgeeks.org.看到你的文章出现在Geeksforgeks主页上，并帮助其他极客。

如果您发现任何不正确的地方，或者您想分享有关上述主题的更多信息，请写下评论。

文章版权归作者所有，未经允许请勿转载。

THE END

Java