java常用API之查找字符串出现次数

/*
*1.先定义一个字符串，以及需要查找的字符串
String st1="nafjfalsnafjlajnafjlkajnafjlakjfnafjlajfnafnafnafnanfanfanfnafnafnfanfanfnafn";
String key="naf";
*2.定义一个计数器用于记录次数
*3.判断是否查找到,如果找到就记录
*4.接着查找第二个位置
*5.循环

*/
public class FindKey//查找数组中一个字符串出现的次数

{
public static void main(String[] args)
{
String st1="nafjfalsnafjlajnafjlkajnafjlakjfnafjlajfnafnafnafnanfanfanfnafnafnfanfanfnafn";
String key1="naf";
String key2="naf";
int count1 = getKey1(st1 , key1);
System.out.print("count1="+count1);
int count2 = getKey2(st1 , key2);
System.out.print("count2="+count2);
}
public static int getKey1(String st1 , String key1)
{
int count = 0;
int index = 0;
while((index = st1.indexOf(key1,index))!=-1)
{
index = index+key1.length();
count++;
}
return count;
}
public static int getKey2(String st1 , String key2)
{
int index = 0;
int count2 = 0;
while((index=st1.indexOf(key2))!=-1)
{
st1 = st1.substring(index+key2.length());
count2++;
}
return count2;
}

}