import java.util.StringTokenizer;

public class StringDemo02 {

//split :特殊符号不适应：. | \ $ + * ，如果要用 加\\

public static void test01() {

String str = "hello|world";

String[] split = str.split("\\|");

for (int i = 0; i < split.length; i++) {

System.out.println(split[i]);

}

}

public static void test02() {

String str = "helloaworld";

StringTokenizer token = new StringTokenizer(str, "a");

while (token.hasMoreElements()) {

System.out.println(token.nextElement());

}

}

//输入一个字符串 ，统计该字符串中某个单字符串出现的次数

/*

helloworld ：

helloworld -> {"h","e","l","l","o",...}

*/

//input:helloworld

public static int test03(String input, String word) {//l

// helloworld -> {"h","e","l","l","o",...}

int count = 0;

String[] strs = new String[input.length()];

for (int i = 0; i < input.length(); i++) {

strs[i] = input.substring(i, i + 1);

if (strs[i].equals(word)) {

count++;

}

}

return count;

}

//input: helloworld "low" ，判断一个字符串中 ， 某个子字符串出现的次数

public static int test04(String input, String llo) {

/*

input: hellowollodxxxllloxxxxxxxx ,llo

*/

// int position = input.indexOf(llo) ;//==-1

// System.out.println(position);

int count = 0;

while (input.indexOf(llo) != -1) {

count++;

input = input.substring(input.indexOf(llo) + 1);

}

return count;

}

public static void test05() {

//indexOf("子字符串"): 子字符串在源字符串中的 位置

//位置->字符

String str = "hexxxoworxxd";

int position = str.indexOf("llo");

System.out.println(position);

//位置->字符

char c = str.charAt(2);

System.out.println(c);

//replace

System.out.println(str);

// str = str.replace('x','y');

// System.out.println(str);

str = str.replace("xow", "AAA");

System.out.println(str);

}

//helloworld :llo

public static void test06() {

StringBuffer sb = new StringBuffer("abc");//String str = "abc";

//str += "aaa"

//abcaaa

sb.append("aaa");//追加

sb.insert(2, "bbb");//插入

System.out.println(sb);

sb.reverse();//逆序

System.out.println(sb);

//String - StringBuffer各自独立， 可以相互转换

//String ->StringBuffer

String a = "hello";

StringBuffer sb2 = new StringBuffer(a);

//StringBuffer ->String

// String b = sb2.toString() ;

// System.out.println(b);

String c = sb2 + "";//任何类型遇到字符串 都会转为字符串

System.out.println(c);

}

//"12345678" -> 12,345,678

public static void test07(String digital) {

StringBuffer sb = new StringBuffer(digital);

for (int i = digital.length() - 3; i > 0; i = i - 3) {

sb.insert(i, ",");

}

System.out.println(sb.toString());

}

public static void main(String[] args) {

// test01();

// test02();

// System.out.println( test03("ooohelloworldoo","o"));

// System.out.println( test04( "hlloelloworllolllod" ,"o"));;

// test05();

// test06();

test07("12345678");

}

}