[Chapter 11] FileReader

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| Chapter 11 The java.io Package |

# FileReader

## Name

FileReader

## Synopsis

Class Name:

  `java.io.FileReader`

Superclass:

  `java.io.InputStreamReader`

Immediate Subclasses:

  None

Interfaces Implemented:

  None

Availability:

  New as of JDK 1.1

## Description

The `FileReader` class represents a character stream that reads data from a file. It is a subclass of `InputStreamReader` that uses a default buffer size (8192 bytes) to read bytes from a file and the default character encoding scheme to convert the bytes to characters. If you need to specify the character encoding or the buffer size, wrap an `InputStreamReader` around a `FileInputStream`.

The file can be specified using a `FileDescriptor`, a `File` object, or a `String` that represents a pathname. All of the constructors can throw a `SecurityException` if the application does not have permission to read from the specified file.

`FileReader` provides a low-level interface for reading character data from a file. You should think about wrapping a `FileReader` with a `BufferedReader` to increase reading efficiency.

If you need to read binary data from a file, you should use a `FileInputStream` wrapped by a `DataInputStream` instead.

## Class Summary

    public class java.io.FileReader extends java.io.InputStreamReader {
      // Constructors
      public FileReader(String fileName);
      public FileReader(File file);
      public FileReader(FileDescriptor fd);
    }

## Constructors

### FileInputStream

#### public FileReader(String fileName) throws FileNotFoundException

Parameters

  `fileName`

    A `String` that contains the pathname of the file to be accessed. The path must conform to the requirements of the native operating system.

Throws

  `FileNotFoundException`

    If the named file cannot be found.

  `SecurityException`

    If the application does not have permission to read the named file.

Description

  This constructor creates a `FileReader` that gets its input from the file named by the specified `String`.

#### public FileReader(File file) throws FileNotFoundException

Parameters

  `file`

    The `File` to use as input.

Throws

  `FileNotFoundException`

    If the named file cannot be found.

  `SecurityException`

    If the application does not have permission to read the named file.

Description

  This constructor creates a `FileReader` that gets its input from the file represented by the specified `File`.

#### public FileReader(FileDescriptor fdObj)

Parameters

  `fdObj`

    The `FileDescriptor` of the file to use as input.

Throws

  `SecurityException`

    If the application does not have permission to read the specified file.

  `NullPointerException`

    If `FileDescriptor` is `null`.

Description

  This constructor creates a `FileReader` that gets its input from the file identified by the given `FileDescriptor`.

## Inherited Methods

Method | Inherited From | Method | Inherited From
--- | --- | --- | ---
`clone()` | `Object` | `close()` | `InputStreamReader`
`equals(Object)` | `Object` | `finalize()` | `Object`
`getClass()` | `Object` | `getEncoding()` | `InputStreamReader`
`hashCode()` | `Object` | `mark(int)` | `Reader`
`markSupported()` | `Reader` | `notify()` | `Object`
`notifyAll()` | `Object` | `read()` | `InputStreamReader`
`read(char[])` | `Reader` | `read(char[], int, int)` | `InputStreamReader`
`ready()` | `InputStreamReader` | `reset()` | `Reader`
`skip(long)` | `Reader` | `toString()` | `Object`
`wait()` | `Object` | `wait(long)` | `Object`
`wait(long, int)` | `Object` |  |

## See Also

`BufferedReader`, `DataInputStream`, `File`, `FileDescriptor`, `FileInputStream`, `FileNotFoundException`, `InputStreamReader`, `IOException`, `NullPointerException`, `Reader`, `SecurityException`

FileOutputStream |  | FileWriter