java_StringBuilder和StringBuffer 用法

 1 public class TestStringBuilder {
 2     public static void main(String[] args) {
 3         StringBuilder sb=new StringBuilder();
 4         //字符串的追加
 5         sb.append("hello");
 6         sb.append(true);
 7         sb.append(‘你‘);
 8         sb.append(100);
 9         System.out.println(sb.toString());//hellotrue你100
10         
11         sb.delete(3, 5);//含头不含尾
12         System.out.println(sb);//heltrue你100
13         sb.deleteCharAt(1);//删除指定位置上的字符
14         System.out.println(sb);//hltrue你100
15         
16         sb.insert(2, ‘好‘);
17         System.out.println(sb);//hl好true你100
18         System.out.println(sb.indexOf("t")+"\t"+sb.indexOf("k"));//3    -1    
19     }
20 }