Java Learning Note--string StringBuffer StringBuilder

String StringBuffer StringBuilder

String http://docs.oracle.com/javase/7/docs/api/

English: http://www.cnblogs.com/YSO1983/archive/2009/12/07/1618564.html

String STR0= "Most normal method of creation";                System.out.println (STR0); Char[] C1 =New Char[3]; c1[0] = ' C '; c1[1] = ' B '; c1[2] = ' a '; String str1=NewString ("string1"); String str2=NewString (C1); System.out.println (str1+ "" + str2);//output string1 CBA                /*string.valueof () It can convert Java primitives (Int,double,boolean, etc.) and objects (object) to String * toString () is a method of an object that converts the object to a string type, The conversion algorithm depends on the actual needs of the type, * basically every object in Java has a ToString method. */        //String Conversions        intI1 = 100; String STR3=integer.tostring (I1); System.out.println ("Integer.tostring:" +STR3);//Output integer.tostring:100//valueOf () for data conversionString Str32 = string.valueof (123456); System.out.println ("String.valueof ():" +str32);//output string.valueof (): 123456//Character Extraction//charAtString STR4 = "A long string!"; System.out.println ("CharAt (3):" +str4.charat (3));//Output Charat (3): O//GetChars ()        Charbuf [] =New Char[6-2]; Str4.getchars (2, 6, buf, 0); System.out.print ("GetChars Output:"); System.out.println (BUF); //output GetChars output: Long//char[] ToCharArray ()System.out.println (Str4.tochararray ());//output a long string! //extracting substringsString STR5 = str4.substring (2,8); System.out.println ("SubString (2,8) output:" +STR5);//output substring (2,8) output: Long S    

StringBuffer http://docs.oracle.com/javase/7/docs/api/

        /** StringBuffer () * stringbuffer (int size) * StringBuffer (String str) * Receives a string variable, Specify the initial contents of the StringBuffer object and reserve 16 additional character space * StringBuffer (charsequence chars)*/StringBuffer SBF=NewStringBuffer ("Hello"); System.out.println ("Buffer =" +SBF); System.out.println ("Length =" +sbf.length ()); System.out.println ("Capacity =" +sbf.capacity ()); System.out.println ("----Reassign buffer size----"); Sbf.ensurecapacity (55); System.out.println ("Buffer =" +SBF); System.out.println ("Length =" +sbf.length ()); System.out.println ("Capacity =" +sbf.capacity ()); System.out.println ("----Set buffer length----"); Sbf.setlength (30); System.out.println ("Buffer =" +SBF); System.out.println ("Length =" +sbf.length ()); System.out.println ("Capacity =" +sbf.capacity ()); 

Output Result:

Buffer == 5=----Re-specify the buffer size----= =5 =----Set the buffer length----= Hello

StringBuilder http://docs.oracle.com/javase/7/docs/api/

In addition to an important distinction, stringbuffer equates to StringBuilder, the difference being that it is not synchronous, meaning it is not thread-safe.

The StringBuilder advantage is faster performance, but you must use StringBuffer when using multi-threading, and you cannot use StringBuilder

Java Learning Note--string StringBuffer StringBuilder