cn.hutool.core.io

Class BOMInputStream

java.lang.Object

java.io.InputStream

cn.hutool.core.io.BOMInputStream

All Implemented Interfaces:

Closeable, AutoCloseable

public class BOMInputStream
extends InputStream

读取带BOM头的流内容，getCharset()方法调用后会得到BOM头的编码，且会去除BOM头
BOM定义：http://www.unicode.org/unicode/faq/utf_bom.html

• 00 00 FE FF = UTF-32, big-endian
• FF FE 00 00 = UTF-32, little-endian
• EF BB BF = UTF-8
• FE FF = UTF-16, big-endian
• FF FE = UTF-16, little-endian

使用：
String enc = "UTF-8"; // or NULL to use systemdefault
FileInputStream fis = new FileInputStream(file);
BOMInputStream uin = new BOMInputStream(fis, enc);
enc = uin.getCharset(); // check and skip possible BOM bytes

参考： http://akini.mbnet.fi/java/unicodereader/UnicodeInputStream.java.txt

Author:

looly

Constructor Summary

Constructors

Constructor and Description
BOMInputStream(InputStream in) 构造
BOMInputStream(InputStream in, String defaultCharset) 构造

Method Summary

Modifier and Type	Method and Description
void	close()
String	getCharset() 获取BOM头中的编码
String	getDefaultCharset() 获取默认编码
protected void	init() Read-ahead four bytes and check for BOM marks.
int	read()

Methods inherited from class java.io.InputStream

available, mark, markSupported, read, read, reset, skip

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

BOMInputStream

public BOMInputStream(InputStream in)

构造

Parameters:

in - 流

BOMInputStream

public BOMInputStream(InputStream in,
                      String defaultCharset)

构造

Parameters:

in - 流

defaultCharset - 默认编码

Method Detail

getDefaultCharset

public String getDefaultCharset()

获取默认编码

Returns:

默认编码

getCharset

public String getCharset()

获取BOM头中的编码

Returns:

编码

close

public void close()
           throws IOException

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Overrides:

close in class InputStream

Throws:

IOException

read

public int read()
         throws IOException

Specified by:

read in class InputStream

Throws:

IOException

init

protected void init()
             throws IOException

Read-ahead four bytes and check for BOM marks.
Extra bytes are unread back to the stream, only BOM bytes are skipped.

Throws:

IOException - 读取引起的异常