Java 中的 Java.io.BufferedInputStream 类
原文:https://www . geesforgeks . org/Java-io-bufferedinputstream-class-Java/
缓冲输入流向另一个输入流添加功能，即缓冲输入并支持标记和重置方法的能力。创建缓冲区输入流时，会创建一个内部缓冲区数组。当读取或跳过流中的字节时，根据需要从包含的输入流中重新填充内部缓冲区，一次填充许多字节。
施工方及说明
- BufferedInputStream(InputStream in):创建一个 BufferedInputStream，并将其参数(输入流)保存在中，以备后用。
- BufferedInputStream(InputStream in，int size) : 创建一个具有指定缓冲区大小的 BufferedInputStream，并将其参数输入流保存在中，以备后用。
方法:
- int available() : 返回 可以从该输入流中读取(或跳过)的字节数的估计值，而不会被该输入流的方法的下一次调用所阻塞。
Syntax:public int available()
throws IOException
Returns: an estimate of the number of bytes that can be
read (or skipped over) from this input stream without blocking.
Throws:
IOException
-
void close() : 关闭此输入流并释放与该流相关联的任何系统资源。
```java Syntax:public void close() throws IOException Overrides: close in class FilterInputStream Throws: IOException
```
- 无效标记(int readlimit) : 标记该输入流中的当前位置。
```java Syntax:public void mark(int readlimit) Overrides: mark in class FilterInputStream Parameters: readlimit - the maximum limit of bytes that can be read before the mark position becomes invalid.
```
- 布尔标记支持():测试该输入流是否支持标记和重置方法。
```java Syntax:public boolean markSupported() Overrides: markSupported in class FilterInputStream Returns: a boolean indicating if this stream type supports the mark and reset methods.
```
- int read() : 从输入流中读取下一个字节的数据。
```java Syntax:public int read() throws IOException Returns: the next byte of data, or -1 if the end of the stream is reached. Throws: IOException
```
- int read(byte[] b，int off，int len) : 从给定的偏移量开始，将该字节输入流中的字节读入指定的字节数组。
```java Syntax:public int read(byte[] b, int off, int len) throws IOException Parameters: b - destination buffer. off - offset at which to start storing bytes. len - maximum number of bytes to read. Returns: the number of bytes read, or -1 if the end of the stream has been reached. Throws: IOException
```
- void reset() : 将此流重新定位到上次在此输入流上调用 mark 方法时的位置。
```java Syntax:public void reset() throws IOException Overrides: reset in class FilterInputStream Throws: IOException
```
- long skip(long n) :Skips over and discards n bytes of data from this input stream
java Syntax:public long skip(long n) throws IOException Parameters: n - the number of bytes to be skipped. Returns: the actual number of bytes skipped. Throws: IOException程序:
```java // Java program to demonstrate working of BufferedInputStream import java.io.BufferedInputStream; import java.io.FileInputStream; import java.io.IOException;
// Java program to demonstrate BufferedInputStream methods class BufferedInputStreamDemo { public static void main(String args[]) throws IOException { // attach the file to FileInputStream FileInputStream fin = new FileInputStream("file1.txt");
BufferedInputStream bin = new BufferedInputStream(fin);
// illustrating available method System.out.println("Number of remaining bytes:" + bin.available());
// illustrating markSupported() and mark() method boolean b=bin.markSupported(); if (b) bin.mark(bin.available());
// illustrating skip method /Original File content: * This is my first line * This is my second line/ bin.skip(4); System.out.println("FileContents :");
// read characters from FileInputStream and // write them int ch; while ((ch=bin.read()) != -1) System.out.print((char)ch);
// illustrating reset() method bin.reset(); while ((ch=bin.read()) != -1) System.out.print((char)ch);
// close the file fin.close(); } } ```
输出:
java Number of remaining bytes:47 FileContents : is my first line This is my second line This is my first line This is my second line下一篇: Java 中的 Java . io . bufferedoutstream 类
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