append、replace、replaceAll、indexof、lastIndexOf、substring、split、match的用法

package tcc.test.string;
/**
* @author tcc:
* @version 创建时间：2020年12月9日 下午4:25:04
* 类说明:String测试
*/
public class stringTest {
public static void main(String[] args) {
//indexOf用法：b字符串在a字符串中存在，则返回索引；没有则返回-1
// String aString = "abcdefg";
// String bString = "cdefg";
// int c = aString.indexOf(bString);
// System.out.println(c); // 2
// int b = aString.indexOf("童");
// System.out.println("b==="+b);

//append用法：字符串拼接，最后一位往前数
StringBuffer buf = new StringBuffer("Hard_");
String aString = "Waxworks ";
// System.out.println("buf===="+buf.append(aString,3,4));//Hard_w
// System.out.println("buf===="+buf.append(aString,3,5));//Hard_w

//replace、replaceall用法：基本相同，常用于字符换的替换，去空格
String bString = aString.replaceAll("W", "w");
String cString = aString.replaceAll("W", "");
String dString = aString.replaceAll(" ", "");
System.out.println("bString=="+bString);
System.out.println("cString=="+cString);
System.out.println("dString=="+dString);

//lastIndexOf用法：获取某个字符最后一个字符的索引下标
//substring用法：字符串截取
String jpgurl = "upload/shjz_db/2019/04/28/dfs_1_01_99_1556436628795_shjz_db_y5v9y5l2J4q6.jpg";
int index = jpgurl.lastIndexOf(".");
System.out.println("index=="+index);//72
String result = jpgurl.substring(index + 1);
String result1 = jpgurl.substring(0,2);
System.out.println("result=="+result);//jpg
System.out.println("result1=="+result1);//up

//split:以某个字符作为分裂，返回一个String数组
String aString1 = "W,a,x,w,o,r,k,s";
String[] array_h = aString1.split(",");
System.out.println("array_h==="+array_h);
//遍历数组
for(String arry:array_h){
System.out.println("arry===="+arry);
}

//contains用法：包含返回true,不包含返回false
String aString2 = "abc";
System.out.println(aString2.contains("a"));

}

}