String Buffer和StringBuilder类-java

Java String Buffer和StringBuilder类

When the string changes, the need and the StringBuilder class String Buffer

• It can be modified several times, but do not generate new unused objects
• StringBuilder class is not thread safe.

• Speed ​​advantage, in the case of safety requirements must be StringBuffer class
  

  public class Test{
    public static void main(String args[]){ StringBuffer sBuffer = new StringBuffer("everyone："); sBuffer.append("say： "); sBuffer.append("Hello，"); sBuffer.append("world"); System.out.println(sBuffer); } } 

  
  

   

• StringBuffer methods

StringBuffer methods

Numbering	method
1	public StringBuffer appen (String s) specified string to this character sequence
2	public StringBuffer reverse () reverse text
3	public StringBuffer delete (int start, int end) delete part of a string
4	public StringBuffer insert (int offset, int i) will be inserted into this sequence int string representation of the parameter
5	replace (int start, int end, String str) replace the character string with the specified string

No.	method
1	int capacity () Returns the current capacity
2	char charAt (int index) Returns the specified sequence char value at index
3	void ensureCapacity (int minimumCapacity) ensure at least equal to the specified minimum capacity
4	void ensureCapacity (int secBegin, int srcEnd , char [] dst, int dstBegin) will be copied to the target sequence string from character array dst
5	int indexOf (String str) Returns the specified substring index of the first occurrence of the string
6	int indexOf (String str, int fromIndex ) starting from the specified index, substring Returns the index of the first occurrence of the string
7	int lastIndexOf (String str) Returns the rightmost occurrence of the specified string index within this string of
8	nt lastIndexOf (String str, int fromIndex ) Returns a String object position of the last occurrence of
9	int length () Returns the length (number of characters)
10	void setCharAt (int index, char ch ) character set for a given index ch
11	void setLength (int newLength) provided the length of the character sequence
12	CharSequence subSequence (int start, int end ) Returns a new character sequence, the character sequence is a subsequence of this sequence
13	String substring (int start) Returns a new String, which contains the character subsequence of this sequence of characters currently contained
14	String substring (int start, int end ) Returns a new String, which contains this sequence of characters currently contained in the subsequence
15	String toString () Returns the string representation of the data sequence