1, Java flow (Stream), file (File), IO
Read console input: Java control input is done by System.in
Multi-character read from the console char [] Input: string read by a read () method from BufferedReader objects,
String read from the console string []: reading a string for an Bufferedreader readLine from the standard input () method
Console output: print, println (), write ()
2、FileInputStream
Read data from the file reads:
Use string type of input file name to create a stream object to read the file
File object can also be used to create a stream object to read an input file, an object file that is created using File () method
3、FileOutputStream
Create a file and write data files
If the output stream before opening the file, the target file does not exist, then the flow will create a file
4, mkdir () Create Folder
mkdirs () to create a folder and all its parent folder
Returns true isDirectiry () method
list () and extract the files contained in the folder list
5, abnormal
Code missing semicolon: java.lang.Error
To do a divisor 0: java.lang.ArithmeticException
Trying to store the wrong type to an object thrown when an array of anomalies: ArrayStoreException
When attempting to cast an object is not an instance of a subclass: ClassCastException
Passed an illegal or incorrect parameter to the method: IIIegalArgumentException
There are many reasons for abnormal, usually containing:
Illegal user input data
To open a file does not exist
A communication network connection is interrupted, the memory overflow or JVM
[Some of these anomalies caused by user error, caused some procedural errors, physical errors caused some]
6, master three types of abnormal
Checked exception: user error or a problem caused by abnormal, compilation time can not be simply ignored
Runtime exceptions: the programmer may be avoided, it can be ignored at compile time
Error: not unusual, the problem is out of control of the programmer. Errors are usually ignored in the code. For example, stack overflow
7, Exception class hierarchy
All exceptions are inherited from java.lang.Exception class subclass: IOException, RuntimeException
Subclass Throwable class: Exception, Error