String 字符串截取

1. String originalFilename = file.getOriginalFilename();
   String flockGroupId = originalFilename.substring(3, originalFilename.indexOf("."));

String s = originalFilename.substring(3);
String[] split = s.split("\.");
3.
String str="1419459573@qq.com";
String str1=str.substring(0, str.indexOf("@"));//截取@之前的字符串
System.out.println(str1);//1419459573
String str2=str.substring(10);
System.out.println(str2);//@qq.com
String str3=str1.concat(str2);
System.out.println(str3);//1419459573@qq.co