[Chapter 11] FileWriter

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| Chapter 11 The java.io Package |

# FileWriter

## Name

FileWriter

## Synopsis

Class Name:

  `java.io.FileWriter`

Superclass:

  `java.io.OutputStreamWriter`

Immediate Subclasses:

  None

Interfaces Implemented:

  None

Availability:

  New as of JDK 1.1

## Description

The `FileWriter` class represents a character stream that writes data to a file. It is a subclass of `OutputStreamWriter` that uses a default buffer size (8192 bytes) to write bytes to a file and the default character encoding scheme to convert characters to bytes. If you need to specify the character encoding or the buffer size, wrap an `OutputStreamWriter` around a `FileOutputStream`.

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 write to the specified file.

`FileWriter` provides a low-level interface for writing character data to a file. You should think about wrapping a `FileWriter` with a `BufferedWriter` to increase writing efficiency.

If you need to write binary data to a file, you should use a `FileOutputStream` wrapped by a `DataOutputStream` or a `PrintStream` instead.

## Class Summary

    public class java.io.FileWriter extends java.io.OutputStreamWriter {
      // Constructors
      public FileWriter(String fileName);
      public FileWriter(String fileName, boolean append);
      public FileWriter(File file);
      public FileWriter(FileDescriptor fd);
    }

## Constructors

### FileWriter

#### public FileWriter(String fileName) throws IOException

Parameters

  `fileName`

    The pathname of the file to use as output.

Throws

  `FileNotFoundException`

    If the named file cannot be found.

  `SecurityException`

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

Description

  This constructor creates a `FileWriter` that sends its output to the file named by the specified `String`.

####

     public FileWriter(String fileName, boolean append) throws IOException

Parameters

  `fileName`

    The pathname of the file to use as output.

  `append`

    Specifies whether or not data is appended to the output stream.

Throws

  `FileNotFoundException`

    If the named file cannot be found.

  `SecurityException`

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

Description

  This constructor creates a `FileWriter` that sends its output to the named file. If `append` is `true`, the stream is positioned at the end of the file, and data is appended to the end of the file. Otherwise, if `append` is `false`, the stream is positioned at the beginning of the file, and any previous data is overwritten.

#### public FileWriter(File file) throws IOException

Parameters

  `file`

    The `File` to use as output.

Throws

  `FileNotFoundException`

    If the named file cannot be found.

  `SecurityException`

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

Description

  This constructor creates a `FileWriter` that sends its output to the file represented by the specified `File` object.

#### public FileWriter(FileDescriptor fdObj)

Parameters

  `fdObj`

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

Throws

  `SecurityException`

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

  `NullPointerException`

    If `FileDescriptor` is `null`.

Description

  This constructor creates a `FileWriter` that sends its output to the file identified by the given `FileDescriptor`.

## Inherited Methods

Method | Inherited From | Method | Inherited From
--- | --- | --- | ---
`clone()` | `Object` | `close()` | `OutputStreamWriter`
`equals(Object)` | `Object` | `finalize()` | `Object`
`flush()` | `OutputStreamWriter` | `getClass()` | `Object`
`getEncoding()` | `OutputStreamWriter` | `hashCode()` | `Object`
`notify()` | `Object` | `notifyAll()` | `Object`
`toString()` | `Object` | `wait()` | `Object`
`wait(long)` | `Object` | `wait(long, int)` | `Object`
`write(int)` | `OutputStreamWriter` | `write(char[])` | `Writer`
`write(char[], int, int)` | `OutputStreamWriter` | `write(String)` | `Writer`
`write(String, int, int)` | `OutputStreamWriter` |  |

## See Also

`BufferedWriter`, `DataOutputStream`, `File`, `FileDescriptor`, `FileNotFoundException`, `FileOutputStream`, `IOException`, `NullPointerException`, `OutputStreamWriter`, `SecurityException`, `Writer`

FileReader |  | FilterInputStream