Data input stream: DataInputStream
DataInputStream(InputStream in)
Data output stream: DataOutputStream
DataOutputStream(OutputStream out)
Memory Operation Flow: means for temporarily storing the information processing program ends, data from memory disappear
Operation byte array
ByteArrayIntputStream
ByteArrayOutputStream
Operating array of characters
charArrayReader
charArrayWriter
String operations
StringReader
StringWriter
Print flow characteristics:
Only operate a destination, the data source can not operate
Any type of data can be operated
If you have activated the automatic refresh automatically refresh
You can stream (stream copy print a text file) file operations
flow:
Elementary streams: stream is directly read and write the file;
Advanced Stream: provides some additional capabilities to the base of the stream
Which stream object can directly manipulate text files it
FileInputStream
FileOutputStream
FileReader
FileWriter
PrintStream
PrintWriter
See the API, the stream object constructor check, if File Type parameter of type String and at the same time, in general, the operation is directly stream files
PrintWriter
1. can operate any type of data
print() println()
2. Enable auto-refresh
PrintWriter pw=new PrintWriter(new FileWriter("pw.txt",true));
Or should call the println method can
This time not only automatically refresh the data also achieved wrap
println () is equivalent to
bw.writer();
bw.newLine();
bw.flush();
Stdio stream
field in a class system: in, out
Each represents a system standard input and output devices
The default input device is a keyboard, an output device is a calculator
System.in type is InputStream
System.out PrintStream type is a subclass of a subclass of FilterOutputStream OutputStream
:( three kinds of keyboard input data)
arg receiving main method parameters General: A
java helloWorld hello world java
B: Scanner (JDK5 later)
Scanner sc=new Scanner(System.in);
String sc=sc.nextLine();
int x=sc.nextInt();
C: the character the buffer flow through the package to achieve the standard input stream
BufferedReader br=new BufferedReader(new InputStreamReader(System.in))
String line=br.readLine();
int i=Integar.parseInt(br.readLine());
Random access stream
RandomAccessFile Overview
RandomAccessFile class does not belong to the stream, is a subclass of the Object class, but it combines the InputStream and OutputStream functionality, support for random read and write access to the file
public RandomAccessFile(String name,String mode):
The first parameter is the path to the file, the second argument is the mode of operation of the document, there are four models, we most commonly called "rw", in this way means I can either read can also write data
Merge Flow:
SequenceInputStream Overview
SequenceInputStream class can stream a plurality of input streams together into one input stream, this stream is also referred to as a combined stream
SequenceInputStream constructor
SequenceInputStream(InputStream s1,InputStream s2)
sequenceInputStream(Enumeration<？extends InputStream> e)
The contents of multiple files written to a text file
Serialization stream:
The objects stored in a text file or streamed in accordance with the same transmission network
objectOnputStream objects --------------> data stream
Deserialized stream:
Object data stream to restore a text file into an object or the network
objectInputStream stream ----------> Object
Achieve serialization:
Note: exception is the sequence (NotSerializableException)
Classes implementing the java.io.Serializable interface enable sequence features, do not implement this interface state can not make any serialization and deserialization (actually there is no method of this interface, similar to the method of this subclass are not referred to marker interface)
We want to know is:
See class implements the serialization interface when trying to solve the problem of the yellow warning line, it can automatically generate a serialized ID value, and this value is generated later, we change any class that reads previous data There is no problem
Note: There may be a class member variables are many, some of us do not want to serialize, ask how to do it, using the transient keyword to declare member variables do not need to serialize