java105-字符串indexof，spilt，substring方法

public class test44 {
     //分割字符串数组
     public static String[] spitString(String resource,String tag){
         return resource.split(tag);
     }
 }
 测试public class test43 {
     public static void main(String[] args){
         //String的indexof
         String mail="javascript.com";
         System.out.println("索引位置"+mail.indexOf('a'));
         System.out.println("索引位置"+mail.indexOf('a',4));
         System.out.println("索引位置"+mail.indexOf("co"));
         //分割字符串方法
         String target="歌谣,小白,小红,小花,小草,小黑";
         String[] str=test44.spitString(target,",");
         for(String s:str){
             System.out.println(s);
         }
         //重载
         String str1=target.substring(3);
         System.out.println(str1);
         String str2=target.substring(3,10);
         System.out.println(str2);
     }
 }