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String method (JDK9)
Constructor: String#String() No-parameter constructor, the default is an "" empty string String#String(java.lang.String) Gives you a char array, it will help you perform ABCD output
GBK Chinese Simplified + Traditional Character Set
GB2312 Chinese Simplified Character Set
As shown below: Give you some traditional characters, which can be displayed according to the default character set, the default is GBK
But if you convert the character set to GB2312, those traditional characters will not be displayed, and some garbled characters will appear.
How to know the default character set in your system? use
Charset.defaultCharset().displayName()
Convert bytes (uniformly returns byte arrays):
Other methods:
As shown below: Remove left and right spaces and lowercase to uppercase writing
Java.lang.String # split (java.lang.String)
Separated by specific characters, regular expressions can be written in the parameters
As shown below: For example, I want to divide 192.168.101 into four parts, how to separate them? is to separate it according to a specific symbol
If it is these 5,564,21341,561,231415,4564,415641,4 with semicolons
Just put a semicolon there.
As shown in the figure below: You can also use regular expressions to separate, for example, writing a | line is to separate them one by one
If you encounter 1564561|15451|89754|54646 with these | symbols
To separate them, you need to add \\|
indexOf(search) returns -1 is not found
The first two are from the front, the latter two are from the back
Locate lookup:
As shown below: It is the writing method of finding a single character and finding a string
As shown below: It is a positioning search, starting from the 13th
