Common Object API (StringBuffer Class)

StringBuffer: String buffer

Features: The composition of the string is achieved through this class.

StringBuffer can be used to delete the contents of the string.

StringBuffer is a container.

Many methods are the same as string.

The StringBuffer is variable-length.

StringBuffer can store different types of data.

Eventually you want to turn it into a string.

Since it is a container object, what function should it have?

1. Add:

StringBuffer append (date);

StringBuffer Insert (index, date)

2. Delete:

StringBuffer Delete (start, end); Contains a header, does not contain a tail.

StringBuffer deletecharat (int index): Deletes the element at the specified position. StringBuffer Delete (0, the length of the buffer);

3. Find:

Char charAt (index);

int indexOf (String);

int lastIndexOf (string);

4, modify:

StringBuffer replace (start, end, String);

void Setcharat (index, String);

General additions and deletions Change C (Create) U (update) R (read) D (delete)

Set Length:

void setLength (int newlength);

Construction Method:

Variable-length arrays:

StringBuffer (int capacity)

 PackageCn.itcast.p2.stringbuffer.demo; Public classStringbufferdemo {/**     * @paramargs*/     Public Static voidMain (string[] args) {/** StringBuffer: Is the string buffer.         * A container for storing data.          * Features: * 1, variable length.         * 2, you can store different types of data.         * 3, eventually to be converted into a string for use.         * 4, you can modify the string. * * * * Since it is a container object.         What functions should be available?         * 1, add: * stringbuffer append (data);         * StringBuffer Insert (index,data);         * 2, Delete: * StringBuffer Delete (start,end): Contains header, does not contain tail.         * StringBuffer deletecharat (int index): Delete the element at the specified position * 3, look for: * char charAt (index);         * int indexOf (string);         * int lastIndexOf (string);         * 4, Modified: * StringBuffer replace (start,end,string);         * void Setcharat (Index,char); * * Delete and change to C (create) U (update) R (read) D (delete) * * **/buffermethoddemo_2 (); }        Private Static voidbuffermethoddemo_2 () {StringBuffer sb=NewStringBuffer ("ABCE"); //Sb.delete (1, 3);//AE//clears the buffer. //Sb.delete (0,sb.length ());//sb = new StringBuffer (); //sb.replace (1, 3, "NBA");//Sb.setcharat (2, ' Q '); //Sb.setlength (10); //System.out.println ("SB:" +SB);//System.out.println ("Len:" +sb.length ());System.out.println (Sb.reverse ()); }    Private Static voidbuffermethoddemo_1 () {StringBuffer sb=NewStringBuffer ("ABCE"); //sb.append ("Xixi");Sb.insert (2, "QQ");    System.out.println (Sb.tostring ()); }     Public Static voidBuffermethoddemo () {//creates a buffer object. StringBuffer SB =NewStringBuffer (); Sb.append (4). Append (false);//. Append ("haha");Sb.insert (1, "haha");//Sb.append (true);System.out.println (SB); }        }

Common Object API (StringBuffer Class)