Wu Yuxiong - born naturally develop common java class library study notes: StringBuffer

public  class StringBufferDemo01 {
     public  static  void main (String args []) { 
        StringBuffer buf = new new StringBuffer ();     // declare StringBuffer object 
        buf.append ( "the Hello");                     // add content to the StringBuffer 
        buf.append ( "World ") .append (" !!! ");         // continuously calling append () method 
        buf.append (" \ the n-");                         // add an escape character 
        buf.append (" digital = ") .append ( . 1) .append ( "\ n-");     // add a digital 
        buf.append ( "character =") .append ( 'C'      ) append ( "\ n").;// add character
        buf.append ( "boolean =") .append ( to true );     // add Boolean 
        System.out.println (buf);             // direct output object, call toString () 
    } 
};

public  class StringBufferDemo02 {
     public  static  void main (String args []) { 
        StringBuffer buf = new new StringBuffer ();     // declare StringBuffer object 
        buf.append ( "the Hello" );         
        Fun (buf);         // pass StringBuffer content 
        System.out .println (buf);     // print 
    }
     public  static  void Fun (StringBuffer S) {         // receiving StringBuffer reference 
        s.append ( "MLDN") .append ( "LiXingHua");     // content of StringBuffer 
    } 
};

public  class StringBufferDemo03 {
     public  static  void main (String args []) { 
        StringBuffer buf = new new StringBuffer ();     // declare StringBuffer object 
        buf.append ( "World !!");         // add content 
        buf.insert (0, " the Hello ");         // add content before the first content 
        System.out.println (buf); 
        buf.insert (to buf.length (), " MLDN ~ ");     // at the end add content 
        System.out.println (buf); 
    } 
};

public  class StringBufferDemo04 {
     public  static  void main (String args []) { 
        StringBuffer buf = new new StringBuffer ();     // declare StringBuffer object 
        buf.append ( "World !!");         // add content 
        buf.insert (0, " hello ");         // added before the first contents 
        String = buf.reverse STR () toString ();.     // content after inversion becomes a String 
        System.out.println (STR);         // the content output 
    } 
};

public  class StringBufferDemo05 {
     public  static  void main (String args []) { 
        StringBuffer buf = new new StringBuffer ();     // declare StringBuffer object 
        buf.append ( "the Hello") .append ( "World !!");         // to StringBuffer add content 
        buf.replace (6,11, "LiXingHua");         // the world's replaces 
        System.out.println ( "replaces following results:" + buf);     // outputting content 
    } 
};

public  class StringBufferDemo06 {
     public  static  void main (String args []) { 
        StringBuffer buf = new new StringBuffer ();     // declare StringBuffer object 
        buf.append ( "the Hello") .append ( "World !!");         // to StringBuffer add content 
        buf.replace (6,11, "LiXingHua");         // the world replaces the 
        String STR = buf.substring (6,15);     // taken content specified range 
        System.out.println ( "replaces after results: "+ STR);     // outputting content 
    } 
};

public  class StringBufferDemo07 {
     public  static  void main (String args []) { 
        StringBuffer buf = new new StringBuffer ();     // declare StringBuffer object 
        buf.append ( "the Hello") .append ( "World !!");         // to StringBuffer add content 
        buf.replace (6, 11, "LiXingHua");         // the world's replaces 
        String str = buf.delete (6, 15) .toString ();     // delete the content in the specified range 
        System.out. println ( "result after:" + STR);     // outputting content 
    } 
};

public  class StringBufferDemo08 {
     public  static  void main (String args []) { 
        StringBuffer buf = new new StringBuffer ();     // declare StringBuffer object 
        buf.append ( "the Hello") .append ( "World !!");         // to StringBuffer add content 
        IF (buf.indexOf ( "the Hello") == -. 1 ) { 
            System.out.println ( "not find the specified content" ); 
        } the else {     // not find the content 01 showing 
            System.out. the println ( "You can find specific content" ); 
        } 
    } 
};

public  class StringBufferDemo09 {
     public  static  void main (String args []) { 
        String str1 = "LiXingHua" ;
         for ( int I = 0; I <100; I ++ ) { 
            str1 + = I;         // continue to modify the memory references a String, low performance 
        } 
        System.out.println (str1); 
    } 
};

public class StringBufferDemo10{
    public static void main(String args[]){
        StringBuffer buf = new StringBuffer() ;
        buf.append("LiXingHua") ;
        for(int i=0;i<100;i++){
            buf.append(i);        // StringBuffer可以修改，性能高
        }
        System.out.println(buf) ;
    }
};