StringBuilder类练习
1 package cn.itcast.p2.stringbuffer.demo; 2 3 public class StringBuilderTest { 4 public static void main(String[] args) { 5 int[] arr = {3,1,5,3,8}; 6 String s = arrayToString(arr); 7 System.out.println(s); 8 System.out.println(arrayToString_2(arr)); 9 } 10 /** 11 * 讲一个int数组变成字符串 12 * @param arr 13 * @return 14 */ 15 public static String arrayToString_2(int[] arr) { 16 StringBuilder sb = new StringBuilder(); 17 sb.append("["); 18 for (int i = 0; i < arr.length; i++) { 19 if(i!=arr.length-1) 20 sb.append(arr[i]+","); 21 else { 22 sb.append(arr[i]+"]"); 23 } 24 } 25 26 return sb.toString(); 27 } 28 29 /** 30 * 讲一个int数组变成字符串 31 * @param arr 32 * @return 33 */ 34 public static String arrayToString(int[] arr) { 35 String str = "["; 36 for (int i = 0; i < arr.length; i++) { 37 if(i!=arr.length-1) 38 str+=arr[i]+",";//连接一次逗号就产生一个字符串常量的成员,循环后产生n多个 39 else { 40 str+=arr[i]+"]"; 41 } 42 } 43 44 return str; 45 } 46 47 //数据越多用容器,集合,stringbuffer,数组 ,这三个容器 48 }