程序包 javax.crypto

类 CipherOutputStream

java.lang.Object

java.io.OutputStream

java.io.FilterOutputStream

javax.crypto.CipherOutputStream

所有已实现的接口:

Closeable, Flushable, AutoCloseable

public class CipherOutputStream
extends FilterOutputStream

A CipherOutputStream is composed of an OutputStream and a Cipher so that write() methods first process the data before writing them out to the underlying OutputStream. The cipher must be fully initialized before being used by a CipherOutputStream.

For example, if the cipher is initialized for encryption, the CipherOutputStream will attempt to encrypt data before writing out the encrypted data.

This class adheres strictly to the semantics, especially the failure semantics, of its ancestor classes java.io.OutputStream and java.io.FilterOutputStream. This class has exactly those methods specified in its ancestor classes, and overrides them all. Moreover, this class catches all exceptions that are not thrown by its ancestor classes. In particular, this class catches BadPaddingException and other exceptions thrown by failed integrity checks during decryption. These exceptions are not re-thrown, so the client will not be informed that integrity checks failed. Because of this behavior, this class may not be suitable for use with decryption in an authenticated mode of operation (e.g. GCM) if the application requires explicit notification when authentication fails. Such an application can use the Cipher API directly as an alternative to using this class.

It is crucial for a programmer using this class not to use methods that are not defined or overriden in this class (such as a new method or constructor that is later added to one of the super classes), because the design and implementation of those methods are unlikely to have considered security impact with regard to CipherOutputStream.

从以下版本开始:

1.4

另请参阅:

OutputStream, FilterOutputStream, Cipher, CipherInputStream

字段概要

从类继承的字段 java.io.FilterOutputStream

out

构造器概要

构造器

限定符	构造器	说明
protected	CipherOutputStream(OutputStream os)	Constructs a CipherOutputStream from an OutputStream without specifying a Cipher.
	CipherOutputStream(OutputStream os, Cipher c)	Constructs a CipherOutputStream from an OutputStream and a Cipher.

方法概要

限定符和类型	方法	说明
void	close()	Closes this output stream and releases any system resources associated with this stream.
void	flush()	Flushes this output stream by forcing any buffered output bytes that have already been processed by the encapsulated cipher object to be written out.
void	write(byte[] b)	Writes b.length bytes from the specified byte array to this output stream.
void	write(byte[] b, int off, int len)	Writes len bytes from the specified byte array starting at offset off to this output stream.
void	write(int b)	Writes the specified byte to this output stream.

从类继承的方法 java.lang.Object

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

构造器详细资料

CipherOutputStream

public CipherOutputStream(OutputStream os,
                          Cipher c)

Constructs a CipherOutputStream from an OutputStream and a Cipher.
Note: if the specified output stream or cipher is null, a NullPointerException may be thrown later when they are used.

参数:

os - the OutputStream object

c - an initialized Cipher object

CipherOutputStream

protected CipherOutputStream(OutputStream os)

Constructs a CipherOutputStream from an OutputStream without specifying a Cipher. This has the effect of constructing a CipherOutputStream using a NullCipher.
Note: if the specified output stream is null, a NullPointerException may be thrown later when it is used.

参数:

os - the OutputStream object

方法详细资料

write

public void write(int b)
           throws IOException

Writes the specified byte to this output stream.

覆盖:

write 在类中 FilterOutputStream

参数:

b - the byte.

抛出:

IOException - if an I/O error occurs.

从以下版本开始:

JCE1.2

write

public void write(byte[] b)
           throws IOException

Writes b.length bytes from the specified byte array to this output stream.

The write method of CipherOutputStream calls the write method of three arguments with the three arguments b, 0, and b.length.

覆盖:

write 在类中 FilterOutputStream

参数:

b - the data.

抛出:

NullPointerException - if b is null.

IOException - if an I/O error occurs.

从以下版本开始:

JCE1.2

另请参阅:

write(byte[], int, int)

write

public void write(byte[] b,
                  int off,
                  int len)
           throws IOException

Writes len bytes from the specified byte array starting at offset off to this output stream.

覆盖:

write 在类中 FilterOutputStream

参数:

b - the data.

off - the start offset in the data.

len - the number of bytes to write.

抛出:

IOException - if an I/O error occurs.

从以下版本开始:

JCE1.2

另请参阅:

FilterOutputStream.write(int)

flush

public void flush()
           throws IOException

Flushes this output stream by forcing any buffered output bytes that have already been processed by the encapsulated cipher object to be written out.

Any bytes buffered by the encapsulated cipher and waiting to be processed by it will not be written out. For example, if the encapsulated cipher is a block cipher, and the total number of bytes written using one of the write methods is less than the cipher's block size, no bytes will be written out.

指定者:

flush 在接口中 Flushable

覆盖:

flush 在类中 FilterOutputStream

抛出:

IOException - if an I/O error occurs.

从以下版本开始:

JCE1.2

另请参阅:

FilterOutputStream.out

close

public void close()
           throws IOException

Closes this output stream and releases any system resources associated with this stream.

This method invokes the doFinal method of the encapsulated cipher object, which causes any bytes buffered by the encapsulated cipher to be processed. The result is written out by calling the flush method of this output stream.

This method resets the encapsulated cipher object to its initial state and calls the close method of the underlying output stream.

指定者:

close 在接口中 AutoCloseable

指定者:

close 在接口中 Closeable

覆盖:

close 在类中 FilterOutputStream

抛出:

IOException - if an I/O error occurs.

从以下版本开始:

JCE1.2

另请参阅:

FilterOutputStream.flush(), FilterOutputStream.out