import java.util.*;
import java.sql.*;


public class Test { public static void main(String[] args) {

     int hour = 1;
     long retryDate = System.currentTimeMillis();
     Timestamp original = new Timestamp(retryDate);

     Calendar cal = Calendar.getInstance();
     cal.setTimeInMillis(original.getTime());
     cal.add(Calendar.HOUR, hour);

     Timestamp later = new Timestamp(cal.getTime().getTime());

     String now = original.toString().substring(0, 19);
     String nowPlus1hr = later.toString().substring(0, 19);

     System.out.println("現在時刻："+ now);
     System.out.println("現在時刻+1時間："+ nowPlus1hr);

  }

}


-------console

現在時刻：2021-01-07 07:06:19
現在時刻+1時間：2021-01-07 08:06:19

String str ="010-1234-5678";
String [] mobNum = str.split("-");
String ret1 = mobNum[0];
String ret2 = mobNum[1];
String ret3 = mobNum[2];

System.out.println("ret1 = "+ ret1);
System.out.println("ret2 = "+ ret2);
System.out.println("ret3 = "+ ret3);

-------console

ret1 = 010
ret1 = 1234
ret1 = 5678

String str2 = "Seoul,Busan,Tokyo";
String[] cityArr = str2.split(",");
for(int i=0; i<cityArr.length; i++)
System.out.println(cityArr[i]);
}

-------console

Seoul
Busan
Tokyo

String str3 = "123-2-456-789";
String[] arr = str3.split("-", 2);
System.out.println("ret4 = " + arr[0]);
System.out.println("ret5 = " + arr[1]);


-------console

ret4 = 123
ret5 = 2-456-789

String str4 = "123-2-456-789-010";
String[] arr4 = str4.split("-", 4);
System.out.println(arr4.length);
for(int i =0; i<arr4.length; i++){
System.out.println("ret" + i + " = " + arr4[i]);
}


-------console
4
ret0 = 123
ret1 = 2
ret2 = 456
ret3 = 789-010

import java.util.Random;


String reset_pw_key1;
String reset_pw_key2;

Random rnd =new Random();
StringBuffer buf =new StringBuffer();
StringBuffer buf1 =new StringBuffer();

// reset_pw_key1の生成
  for(int j=0;j<16;j++){

      if(rnd.nextBoolean()){

          buf.append((char)((int)(rnd.nextInt(26))+97));

      }else{

          buf.append((rnd.nextInt(10)));

      }
  }

    reset_pw_key1 = buf.toString();
    System.out.println("reset_pw_key1 : " + reset_pw_key1);

// reset_pw_key2の生成
  for(int j=0;j<16;j++){

      if(rnd.nextBoolean()){

          buf1.append((char)((int)(rnd.nextInt(26))+97));

      }else{

          buf1.append((rnd.nextInt(10)));

      }
  }
    reset_pw_key2 = buf1.toString();
    System.out.println("reset_pw_key2 : " + reset_pw_key2);
    }
}

------Console
reset_pw_key1 : 12v9nl26m1e1k44u
reset_pw_key2 : m52ip21t2c6xnwa7

import org.apache.commons.io.FilenameUtils;

public class test {
   
    public static void main(String [] args) {
        
        filenameComponents_();
    }
 
    private static void filenameComponents_() {
     
        String filename = "ABC.png";
        System.out.println("*** File name components ***");
        System.out.println("File name: " + filename);

        String name = FilenameUtils.getName(filename);
        System.out.println("Name: " + name);
         
        String baseName = FilenameUtils.getBaseName(filename);
        System.out.println("Base name: " + baseName);
         
        String extension = FilenameUtils.getExtension(filename);
        System.out.println("Extension: " + extension);
    }
}


------Console
*** File name components ***
File name: ABC.png
Name: ABC.png
Base name: ABC
Extension: png