java String 类的基本方法

1.String.subString(int i )字符串截取，从第i个字符串截取直到字符串的末尾。

2.String.subString(int beginindex,int endindex)从beginindex开始截取到endindex。

public class SubString {
public static void main(String[] args) {
String a =" this is my food";
/*System.out.println("index of letter 's' ="+a.indexOf('s'));
System.out.println("index of letter 'o'="+a.indexOf('a'));*/
System.out.println(a.substring(2));
System.out.println(a.substring(2, 4));
}
}

运行结果:

his is my food

hi

3.String.charAt(i) 返回指定索引值出的char值。索引的范围是从0 到length-1。

public class SubString {
public static void main(String[] args) {
String a =" this is my food";
System.out.println(a.charAt(2));
}
}

运行结果:h。