Java programming notes 5: stringbuffer and stringtokenizer

1. String Array Constructor: String [] array = new string [5]; String [] array = new string [] {"AA", "BB", "CC "}; String [] array = {"AA", "BB", "CC "}; String arrays are also seen as objects: Attribute: length (different from the string method length ()) Common Methods: void system. arraycopy (object [] From, intfromindex, object [] to, int fromindex, int count), a static method of the system 2. String cache stringbuffer Once declared, the string class object cannot be changed. The stringbuffer cache class implements a variable character sequence. The basic operations on stringbuffer are append and insert. They accept arbitrary data, convert the given data to a string, and add the string to the end of the buffer or insert it to the specified place. Public final classStringbuffer Extends object Implements serializable, charsequence Constructor Summary Stringbuffer() Construct a string buffer with no characters. The initial size is 16 characters. Stringbuffer(Charsequence SEQ) Public java. Lang. stringbuilder (charsequence SEQ) constructs a string buffer that contains the same characters as the specified charsequence. Stringbuffer(INT capacity) Construct a string buffer with no characters but a specified initial capacity. Stringbuffer(String Str) Constructs a string buffer and initializes its content to the specified string content. Other methods: Stringbuffer is converted to a string object: tostring () String Tostring() Returns a string representing the data in this sequence. Stringbuffer extension appand (): Stringbuffer Append(Boolean B) Appends the string representation of the Boolean argument to the sequence. Stringbuffer Append(Char C) Appends the string representation of the char argument to this sequence. Stringbuffer Append(Char [] Str) Appends the string representation of the char array argument to this sequence. Stringbuffer Append(Char [] STR, int offset, int Len) Appends the string representation of a subarray of the char array argument to this sequence. Stringbuffer Append(Charsequence S) Add the specified charsequence to the sequence. Stringbuffer Append(Charsequence S, int start, int end) Appends a subsequence of the specified charsequence to this sequence. Wait ....... Any type will be converted into strings and added to the cache end Insert () of stringbuffer (): Stringbuffer Insert(INT offset, object OBJ) Inserts the string representation of the object argument into this character sequence. Stringbuffer Insert(INT offset, string Str) Inserts the string into this character sequence. Stringbuffer Insert(INT offset, char [] Str) Inserts the string representation of the char array argument into this sequence. Stringbuffer Insert(INT index, char [] STR, int offset, int Len) Inserts the string representation of a subarray of the STR array argument into this sequence. Wait ...... Other typical operations: Int Length() Returns the length (character count ). Char Charat(INT index) Returns the char value in this sequence at the specified index. String Substring(INT start) Returns a new string that contains a subsequence of characters currently contained in this character sequence. Int Indexof(StringStr) Returns the index within this string of the first occurrence of the specified substring. Stringbuffer Replace(INT start, int end,StringStr) Replaces the characters in a substring of this sequence with characters in the specified string. Stringbuffer Delete(INT start, int end) Removes the characters in a substring of this sequence. And so on .....