com.fr.base.frpx.util

枚举 FileMagic

java.lang.Object

java.lang.Enum<FileMagic>

com.fr.base.frpx.util.FileMagic

所有已实现的接口:

java.io.Serializable, java.lang.Comparable<FileMagic>

public enum FileMagic
extends java.lang.Enum<FileMagic>

The file magic number, i.e. the file identification based on the first bytes of the file

枚举常量概要

枚举常量

枚举常量和说明
PDF PDF document
UNKNOWN UNKNOWN magic
XML XML file
ZIP ZIP stream

方法概要

方法

限定符和类型	方法和说明
static void	copy(java.io.InputStream inp, java.io.OutputStream out)
static byte[]	peekFirst8Bytes(java.io.InputStream stream) Peeks at the first 8 bytes of the stream.
static byte[]	peekFirstNBytes(java.io.InputStream stream, int limit) Peeks at the first N bytes of the stream.
static java.io.InputStream	prepareToCheckMagic(java.io.InputStream stream) Checks if an InputStream can be reseted (i.e. used for checking the header magic) and wraps it if not
static FileMagic	valueOf(byte[] magic)
static FileMagic	valueOf(java.io.InputStream inp) Get the file magic of the supplied InputStream (which MUST support mark and reset).
static FileMagic	valueOf(java.lang.String name) 返回带有指定名称的该类型的枚举常量。
static FileMagic[]	values() 按照声明该枚举类型的常量的顺序, 返回 包含这些常量的数组。

从类继承的方法 java.lang.Enum

clone, compareTo, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

从类继承的方法 java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

枚举常量详细资料

ZIP

public static final FileMagic ZIP

ZIP stream

XML

public static final FileMagic XML

XML file

PDF

public static final FileMagic PDF

PDF document

UNKNOWN

public static final FileMagic UNKNOWN

UNKNOWN magic

方法详细资料

values

public static FileMagic[] values()

按照声明该枚举类型的常量的顺序, 返回 包含这些常量的数组。该方法可用于迭代 常量, 如下所示:

for (FileMagic c : FileMagic.values())
    System.out.println(c);

返回:

按照声明该枚举类型的常量的顺序返回的包含这些常量的数组

valueOf

public static FileMagic valueOf(java.lang.String name)

返回带有指定名称的该类型的枚举常量。 字符串必须与用于声明该类型的枚举常量的 标识符完全匹配。(不允许有多余 的空格字符。)

参数:

name - 要返回的枚举常量的名称。

返回:

返回带有指定名称的枚举常量

抛出:

java.lang.IllegalArgumentException - 如果该枚举类型没有带有指定名称的常量

java.lang.NullPointerException - 如果参数为空值

valueOf

public static FileMagic valueOf(byte[] magic)

valueOf

public static FileMagic valueOf(java.io.InputStream inp)
                         throws java.io.IOException

Get the file magic of the supplied InputStream (which MUST support mark and reset).

If unsure if your InputStream does support mark / reset, use prepareToCheckMagic(InputStream) to wrap it and make sure to always use that, and not the original!

Even if this method returns UNKNOWN it could potentially mean, that the ZIP stream has leading junk bytes

参数:

inp - An InputStream which supports either mark/reset

抛出:

java.io.IOException

prepareToCheckMagic

public static java.io.InputStream prepareToCheckMagic(java.io.InputStream stream)

Checks if an InputStream can be reseted (i.e. used for checking the header magic) and wraps it if not

参数:

stream - stream to be checked for wrapping

返回:

a mark enabled stream

peekFirst8Bytes

public static byte[] peekFirst8Bytes(java.io.InputStream stream)
                              throws java.io.IOException,
                                     EmptyFileException

Peeks at the first 8 bytes of the stream. Returns those bytes, but with the stream unaffected. Requires a stream that supports mark/reset, or a PushbackInputStream. If the stream has >0 but <8 bytes, remaining bytes will be zero.

抛出:

EmptyFileException - if the stream is empty

java.io.IOException

peekFirstNBytes

public static byte[] peekFirstNBytes(java.io.InputStream stream,
                     int limit)
                              throws java.io.IOException,
                                     EmptyFileException

Peeks at the first N bytes of the stream. Returns those bytes, but with the stream unaffected. Requires a stream that supports mark/reset, or a PushbackInputStream. If the stream has >0 but <N bytes, remaining bytes will be zero.

抛出:

EmptyFileException - if the stream is empty

java.io.IOException

copy

public static void copy(java.io.InputStream inp,
        java.io.OutputStream out)
                 throws java.io.IOException

抛出:

java.io.IOException