Java 简明教程
Java.io.FileInputStream Class
Introduction
Java.io.FileInputStream 类从文件系统中的文件获取输入字节。可用文件取决于主机环境。以下是 FileInputStream 的重要要点：
The Java.io.FileInputStream class obtains input bytes from a file in a file system. What files are available depends on the host environment. Following are the important points about FileInputStream −
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This class is meant for reading streams of raw bytes such as image data.
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For reading streams of characters, use FileReader.
Class declaration
以下是 Java.io.FileInputStream 类的声明：
Following is the declaration for Java.io.FileInputStream class −
public class FileInputStream
extends InputStreamClass constructors
Sr.No. |
Constructor & Description |
1 |
FileInputStream(File file) This creates a FileInputStream by opening a connection to an actual file, the file named by the File object file in the file system. |
2 |
FileInputStream(FileDescriptor fdObj) This creates a FileInputStream by using the file descriptor fdObj, which represents an existing connection to an actual file in the file system. |
3 |
FileInputStream(String name) This creates a FileInputStream by opening a connection to an actual file, the file named by the path name name in the file system. |
Class methods
Sr.No. |
Method & Description |
1 |
int available()This method returns an estimate of the number of remaining bytes that can be read (or skipped over) from this input stream without blocking by the next invocation of a method for this input stream. |
2 |
void close()This method closes this file input stream and releases any system resources associated with the stream. |
3 |
protected void finalize()This method ensures that the close method of this file input stream is called when there are no more references to it. |
4 |
FileChannel getChannel()This method returns the unique FileChannel object associated with this file input stream. |
5 |
FileDescriptor getFD()This method returns the FileDescriptor object that represents the connection to the actual file in the file system being used by this FileInputStream. |
6 |
int read()This method reads a byte of data from this input stream. |
7 |
int read(byte[] b)This method reads up to b.length bytes of data from this input stream into an array of bytes. |
8 |
int read(byte[] b, int off, int len)This method reads up to len bytes of data from this input stream into an array of bytes. |
9 |
long skip(long n)This method skips over and discards n bytes of data from the input stream. |