📅  最后修改于: 2020-11-15 03:07:59             🧑  作者: Mango
java.lang.StringBuffer类是线程安全的可变字符序列。以下是关于StringBuffer的要点-
字符串缓冲区类似于字符串,但是可以修改。
它包含一些特定的字符序列,但是可以通过某些方法调用来更改序列的长度和内容。
它们可以安全地被多个线程使用。
每个字符串缓冲区都有一个容量。
以下是java.lang.StringBuffer类的声明-
public final class StringBuffer
extends Object
implements Serializable, CharSequence
Sr.No. | Constructor & Description |
---|---|
1 |
StringBuffer() This constructs a string buffer with no characters in it and an initial capacity of 16 characters. |
2 |
StringBuffer(CharSequence seq) This constructs a string buffer that contains the same characters as the specified CharSequence. |
3 |
StringBuffer(int capacity) This constructs a string buffer with no characters in it and the specified initial capacity. |
4 |
StringBuffer(String str) This constructs a string buffer initialized to the contents of the specified string. |
Sr.No. | Method & Description |
---|---|
1 | StringBuffer append(boolean b)
This method appends the string representation of the boolean argument to the sequence |
2 | StringBuffer append(char c)
This method appends the string representation of the char argument to this sequence. |
3 | StringBuffer append(char[] str)
This method appends the string representation of the char array argument to this sequence. |
4 | StringBuffer append(char[] str, int offset, int len)
This method appends the string representation of a subarray of the char array argument to this sequence. |
5 | StringBuffer append(CharSequence s)
This method appends the specified CharSequence to this sequence. |
6 | StringBuffer append(CharSequence s, int start, int end)
This method appends a subsequence of the specified CharSequence to this sequence. |
7 | StringBuffer append(double d)
This method appends the string representation of the double argument to this sequence. |
8 | StringBuffer append(float f)
This method appends the string representation of the float argument to this sequence. |
9 | StringBuffer append(int i)
This method appends the string representation of the int argument to this sequence. |
10 | StringBuffer append(long lng)
This method appends the string representation of the long argument to this sequence. |
11 | StringBuffer append(Object obj)
This method appends the string representation of the Object argument. |
12 | StringBuffer append(String str)
This method appends the specified string to this character sequence. |
13 | StringBuffer append(StringBuffer sb)
This method appends the specified StringBuffer to this sequence. |
14 | StringBuffer appendCodePoint(int codePoint)
This method appends the string representation of the codePoint argument to this sequence. |
15 | int capacity()
This method returns the current capacity. |
16 | char charAt(int index)
This method returns the char value in this sequence at the specified index. |
17 | int codePointAt(int index)
This method returns the character (Unicode code point) at the specified index |
18 | int codePointBefore(int index)
This method returns the character (Unicode code point) before the specified index |
19 | int codePointCount(int beginIndex, int endIndex)
This method returns the number of Unicode code points in the specified text range of this sequence |
20 | StringBuffer delete(int start, int end)
This method removes the characters in a substring of this sequence. |
21 | StringBuffer deleteCharAt(int index)
This method removes the char at the specified position in this sequence |
22 | void ensureCapacity(int minimumCapacity)
This method ensures that the capacity is at least equal to the specified minimum. |
23 | void getChars(int srcBegin, int srcEnd, char[] dst, int dstBegin)
This method characters are copied from this sequence into the destination character array dst. |
24 | int indexOf(String str)
This method returns the index within this string of the first occurrence of the specified substring. |
25 | int indexOf(String str, int fromIndex)
This method returns the index within this string of the first occurrence of the specified substring, starting at the specified index. |
26 | StringBuffer insert(int offset, boolean b)
This method inserts the string representation of the boolean argument into this sequence. |
27 | StringBuffer insert(int offset, char c)
This method inserts the string representation of the char argument into this sequence. |
28 | StringBuffer insert(int offset, char[] str)
This method inserts the string representation of the char array argument into this sequence. |
29 | StringBuffer insert(int index, char[] str, int offset, int len)
This method inserts the string representation of a subarray of the str array argument into this sequence. |
30 | StringBuffer insert(int dstOffset, CharSequence s)
This method inserts the specified CharSequence into this sequence. |
31 | StringBuffer insert(int dstOffset, CharSequence s, int start, int end)
This method inserts a subsequence of the specified CharSequence into this sequence. |
32 | StringBuffer insert(int offset, double d)
This method inserts the string representation of the double argument into this sequence. |
33 | StringBuffer insert(int offset, float f)
This method inserts the string representation of the float argument into this sequence. |
34 | StringBuffer insert(int offset, int i
This method inserts the string representation of the second int argument into this sequence. |
35 | StringBuffer insert(int offset, long l)
This method inserts the string representation of the long argument into this sequence. |
36 | StringBuffer insert(int offset, Object obj)
This method inserts the string representation of the Object argument into this character sequence. |
37 | StringBuffer insert(int offset, String str)
This method inserts the string into this character sequence. |
38 | int lastIndexOf(String str)
This method returns the index within this string of the rightmost occurrence of the specified substring. |
39 | int lastIndexOf(String str, int fromIndex)
This method returns the index within this string of the last occurrence of the specified substring. |
40 | int length()
This method returns the length (character count). |
41 | int offsetByCodePoints(int index, int codePointOffset)
This method returns the index within this sequence that is offset from the given index by codePointOffset code points. |
42 | StringBuffer replace(int start, int end, String str)
This method replaces the characters in a substring of this sequence with characters in the specified String. |
43 | StringBuffer reverse()
This method causes this character sequence to be replaced by the reverse of the sequence. |
44 | void setCharAt(int index, char ch)
The character at the specified index is set to ch. |
45 | void setLength(int newLength)
This method sets the length of the character sequence. |
46 | CharSequence subSequence(int start, int end)
This method returns a new character sequence that is a subsequence of this sequence. |
47 | String substring(int start)
This method returns a new String that contains a subsequence of characters currently contained in this character sequence |
48 | String substring(int start, int end)
This method returns a new String that contains a subsequence of characters currently contained in this sequence. |
49 | String toString()
This method returns a string representing the data in this sequence. |
50 | void trimToSize()
This method attempts to reduce storage used for the character sequence. |
此类从以下类继承方法-