1 import java.text.*; 2 public class Gxjun 3 { 4 public static void main(String atgs[]) 5 { 6 StringBuffer str= new StringBuffer(); 7 str.append("大家好"); 8 System.out.println("str:"+str); 9 System.out.println("length:"+str.length()); 10 System.out.println("capacity:"+str.capacity()); 11 str.setCharAt(0,'w'); 12 str.setCharAt(1,'e'); 13 System.out.println(str); 14 str.insert(2, "are all"); 15 System.out.println(str); 16 int index=str.indexOf("好"); 17 str.replace(index, str.length(),"right"); 18 System.out.println(str); 19 } 20 }