Sample of Java8 time library

Java8TimeLibraryTest.java

package com.orb.framework;

import static java.time.format.DateTimeFormatter.ofPattern;
import static org.junit.Assert.fail;

import java.time.Instant;
import java.time.LocalDateTime;
import java.time.ZoneId;
import java.time.ZoneOffset;
import java.time.ZonedDateTime;
import java.time.format.DateTimeFormatter;
import java.time.format.DateTimeFormatterBuilder;
import java.time.format.DateTimeParseException;
import org.junit.Test;

public class InstantTest {

  @Test
  public void instantTest() {
    Instant i1 = LocalDateTime.of(2018,5,1,11,11,11,100000000).toInstant(ZoneOffset.UTC);
    Instant i2 = LocalDateTime.of(2018,5,1,11,11,11,0).toInstant(ZoneOffset.UTC);
    Instant i3 = LocalDateTime.of(2018,5,1,11,11,0,0).toInstant(ZoneOffset.UTC);
    Instant i4 = LocalDateTime.of(2018,5,1,11,0,0,0).toInstant(ZoneOffset.UTC);
    Instant i5 = LocalDateTime.of(2018,5,1,0,0,0,0).toInstant(ZoneOffset.UTC);
    System.out.println(i1);
    System.out.println(i2);
    System.out.println(i3);
    System.out.println(i4);
    System.out.println(i5);

    System.out.println("==== toString ====");
    System.out.println(i1.toString());
    System.out.println(i2.toString());
    System.out.println(i3.toString());
    System.out.println(i4.toString());
    System.out.println(i5.toString());
  }

  @Test
  public void formatterTest2() {
    DateTimeFormatter formatter = ofPattern("yyyy-MM-dd'T'HH:mm:ss'Z'");
    assertFormat("2018-04-12T08:49:07Z", formatter, ZoneOffset.UTC);
  }

  @Test
  public void formatterTest5() {
    DateTimeFormatterBuilder builder = new DateTimeFormatterBuilder()
        .append(ofPattern("yyyy-MM-dd'T'HH:mm:ss"))
        .appendOptional(ofPattern(".SSS"))
        .appendOptional(ofPattern("'Z'"));
    DateTimeFormatter formatter = builder.toFormatter();
    assertFormat("2018-04-12T08:49:07Z", formatter, ZoneId.of("Asia/Tokyo"));
    assertFormat("2018-04-12T08:49:07.237Z", formatter, ZoneId.of("Asia/Tokyo"));
  }

  @Test
  public void expressionTest() {
//    for (String z : ZoneId.getAvailableZoneIds()) {
//      System.out.println(z);
//    }
    ZonedDateTime znow = ZonedDateTime.now(ZoneId.of("Asia/Tokyo"));
    System.out.println(DateTimeFormatter.ofPattern("yyyy/MM/dd HH:mm:ss").format(znow));
    //znow = ZonedDateTime.now(ZoneOffset.UTC);
    znow = ZonedDateTime.now(ZoneId.of("UTC"));
    System.out.println(DateTimeFormatter.ofPattern("yyyy/MM/dd HH:mm:ss").format(znow));
  }

  public void assertFormat(String raw, DateTimeFormatter formatter, ZoneId zone) {
    try {
      LocalDateTime localDate = LocalDateTime.parse(raw, formatter);
      ZonedDateTime zLocalDate = ZonedDateTime.of(localDate, zone);
    } catch (DateTimeParseException e) {
      e.printStackTrace();
      fail();
    }
  }

}