Common API (a) in Java

StringBuffer

In order to solve the village that day redundancy String string manipulation leads to improve efficiency, Java and StrinBuilder provided StringBuffer to manipulate strings, and provides a number of ways to facilitate programmers to develop.

StringBuffer and StringBuilder in both the char type variable-length string is stored as an array of space. ArrayList using the method and the like.

StringBuffer thread-safe, low efficiency.

StringBuilder thread-safe, high efficiency

StringBuffer constructor

StringBuffer（）；

Create an empty StringBuffer any space to store the character string information, an array of a char type underlying initialization character 16

StringBuffer（String str）；

Create a String corresponding to the type of the supplied string StringBuffer space, the capacity of the underlying array of type char str.length + 16 based on the decision, and holds the corresponding str.

Add Method

append（Everything）

In StringBuffer and StringBuilder objects, additional data, and as strings.

insert（int index ， Everything）

In StringBuffer and StringBuilder object at a specified index position, add anything else, and as strings

Check method

String toString();

The bottom of the char conversion character type array to hold the contents to the corresponding

String type string is returned

int length();

Back underlying char what an effective element type has an array.

String substring(int begin);

Acquired from the start position to the specified char the end of the active element array corresponding to the type of

String capture operation,

String substring(int begin, int end);

From the specified location begin start to end end, obtaining a corresponding character string,

Do not head to tail

int indexOf(String str);

Element specifies the character string indexing position

int lastIndexOf(String str);

The last time the specified element string where the subscript position