java string and stitching interception

public static void main(String[] args) {
String sendContent = "请查收:www.baidu.com";

// query the last position of a string colon
int index = sendContent.lastIndexOf ( ":" );

//截取
String qian = sendContent.substring(0, index);
String houb = sendContent.substring(index);

//拼接
String all= qian.concat("http").concat(houb);

System.out.println(houb);
System.out.println(qian);
System.out.println(all);
}