com.aliyun.odps.io

Class WritableUtils

java.lang.Object

com.aliyun.odps.io.WritableUtils

public final class WritableUtils
extends Object

Writable 工具类.

Constructor Summary

Constructors

Constructor and Description
WritableUtils()

Method Summary

Modifier and Type	Method and Description
static <T extends Writable> T	clone(T orig, Configuration conf) 通过Writable序列化方式拷贝一个Writable对象.
static int	decodeVIntSize(byte value) 解析vint、vlong的首字节（表示其本身的长度）
static void	displayByteArray(byte[] record) 打印出byte数组的字符串形式
static int	getVIntSize(long i) 获取变长的int长度
static boolean	isNegativeVInt(byte value) 解析vint、vlong的首字节判断其是否为负值
static byte[]	readCompressedByteArray(DataInput in) 读取压缩的二进制输入流
static String	readCompressedString(DataInput in) 从二进制输入流中读取压缩的字符串
static String[]	readCompressedStringArray(DataInput in) 从二进制输入流中读取压缩的字符串数组
static <T extends Enum<T>> T	readEnum(DataInput in, Class<T> enumType) 从输入流中读取枚举值
static String	readString(DataInput in) 从二进制输入流中读取字符串
static String[]	readStringArray(DataInput in) 从二进制输入流中读取字符串数组
static int	readVInt(DataInput stream) 从二进制流中读取vint.
static long	readVLong(DataInput stream) 从二进制流中读取vlong.
static void	skipCompressedByteArray(DataInput in)
static void	skipFully(DataInput in, int len) 输入流中跳过指定长度的字节
static byte[]	toByteArray(Writable... writables) 将Writable对象转化成byte数组
static int	writeCompressedByteArray(DataOutput out, byte[] bytes) 压缩写入byte数组到二进制输出流中
static int	writeCompressedString(DataOutput out, String s) 压缩写入字符串到二进制输出流中
static void	writeCompressedStringArray(DataOutput out, String[] s) 压缩写入字符串数组到二进制输出流中
static void	writeEnum(DataOutput out, Enum<?> enumVal) 写入枚举到输出流
static void	writeString(DataOutput out, String s) 写入字符串到二进制输出流中
static void	writeStringArray(DataOutput out, String[] s) 写入字符串数组到二进制输出流中
static void	writeVInt(DataOutput stream, int i) vint方式序列化一个int到二进制输出流中
static void	writeVLong(DataOutput stream, long i) vlong方式序列化一个long到二进制输出流中

Methods inherited from class java.lang.Object

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

Constructor Detail

WritableUtils

public WritableUtils()

Method Detail

readCompressedByteArray

public static byte[] readCompressedByteArray(DataInput in)
                                      throws IOException

读取压缩的二进制输入流

Parameters:

in - 二进制输入流

Returns:

读取的二进制数据

Throws:

IOException

skipCompressedByteArray

public static void skipCompressedByteArray(DataInput in)
                                    throws IOException

Throws:

IOException

writeCompressedByteArray

public static int writeCompressedByteArray(DataOutput out,
                                           byte[] bytes)
                                    throws IOException

压缩写入byte数组到二进制输出流中

Parameters:

out - 二进制输出流

s - 写入的byte数组

Throws:

IOException

readCompressedString

public static String readCompressedString(DataInput in)
                                   throws IOException

从二进制输入流中读取压缩的字符串

Parameters:

in - 二进制输入流

Returns:

读取的字符串

Throws:

IOException

writeCompressedString

public static int writeCompressedString(DataOutput out,
                                        String s)
                                 throws IOException

压缩写入字符串到二进制输出流中

Parameters:

out - 二进制输出流

s - 写入的字符串

Throws:

IOException

writeString

public static void writeString(DataOutput out,
                               String s)
                        throws IOException

写入字符串到二进制输出流中

Parameters:

out - 二进制输出流

s - 写入的字符串

Throws:

IOException

readString

public static String readString(DataInput in)
                         throws IOException

从二进制输入流中读取字符串

Parameters:

in - 二进制输入流

Returns:

读取的字符串

Throws:

IOException

writeStringArray

public static void writeStringArray(DataOutput out,
                                    String[] s)
                             throws IOException

写入字符串数组到二进制输出流中

Parameters:

out - 二进制输出流

s - 字符串数组

Throws:

IOException

writeCompressedStringArray

public static void writeCompressedStringArray(DataOutput out,
                                              String[] s)
                                       throws IOException

压缩写入字符串数组到二进制输出流中

Parameters:

out - 二进制输出流

s - 字符串数组

Throws:

IOException

readStringArray

public static String[] readStringArray(DataInput in)
                                throws IOException

从二进制输入流中读取字符串数组

Parameters:

in - 二进制输入流

Returns:

字符串数组

Throws:

IOException

readCompressedStringArray

public static String[] readCompressedStringArray(DataInput in)
                                          throws IOException

从二进制输入流中读取压缩的字符串数组

Parameters:

in - 二进制输入流

Returns:

字符串数组

Throws:

IOException

displayByteArray

public static void displayByteArray(byte[] record)

打印出byte数组的字符串形式

Parameters:

record - byte数组

writeVInt

public static void writeVInt(DataOutput stream,
                             int i)
                      throws IOException

vint方式序列化一个int到二进制输出流中

Parameters:

stream - 二进制输出流

i - int的值

Throws:

IOException

writeVLong

public static void writeVLong(DataOutput stream,
                              long i)
                       throws IOException

vlong方式序列化一个long到二进制输出流中

Parameters:

stream - 二进制输出流

i - long的值

Throws:

IOException

readVLong

public static long readVLong(DataInput stream)
                      throws IOException

从二进制流中读取vlong.

Parameters:

stream - 输入二进制流

Returns:

vlong值

Throws:

IOException

readVInt

public static int readVInt(DataInput stream)
                    throws IOException

从二进制流中读取vint.

Parameters:

stream - 输入二进制流

Returns:

vint值

Throws:

IOException

isNegativeVInt

public static boolean isNegativeVInt(byte value)

解析vint、vlong的首字节判断其是否为负值

Parameters:

value - vint、vlong的首字节

Returns:

是否为负值

decodeVIntSize

public static int decodeVIntSize(byte value)

解析vint、vlong的首字节（表示其本身的长度）

Parameters:

value - vint、vlong的首字节

Returns:

字节长度(1 - 9)

getVIntSize

public static int getVIntSize(long i)

获取变长的int长度

Parameters:

i - int值

Returns:

变长的int长度

readEnum

public static <T extends Enum<T>> T readEnum(DataInput in,
                                             Class<T> enumType)
                                      throws IOException

从输入流中读取枚举值

Type Parameters:

T - Enum 枚举类型

Parameters:

in - 输入流

enumType - 枚举类

Returns:

Enum 读取枚举值

Throws:

IOException

writeEnum

public static void writeEnum(DataOutput out,
                             Enum<?> enumVal)
                      throws IOException

写入枚举到输出流

Parameters:

out - 输出流

enumVal - 枚举值

Throws:

IOException

skipFully

public static void skipFully(DataInput in,
                             int len)
                      throws IOException

输入流中跳过指定长度的字节

Parameters:

in - 输入流

len - 指定字节长度

Throws:

IOException

toByteArray

public static byte[] toByteArray(Writable... writables)

将Writable对象转化成byte数组

Parameters:

writables - Writable对象集合

Returns:

转化后二进制数据

clone

public static <T extends Writable> T clone(T orig,
                                           Configuration conf)

通过Writable序列化方式拷贝一个Writable对象.

Parameters:

orig - 拷贝源对象

Returns:

拷贝对象

Throws:

IOException