Java Basics 1.08

Using Equality Operators

 

 

Code:

public class Main {

 

    public static void main(String[] args) {

      String s1 = ("Welcome to California");

      String s2 = new String("Welcome to California");

      System.out.println(s2);

      

      if (s1 == s2) { //comparing OBJECTS not VALUES

            System.out.println("With == They match");

      }

      else {

            System.out.println("With == No match");

      }

      

      if (s1.equals(s2)) { //case sensitive

            System.out.println("With .equals() They match");

      } else {

            System.out.println("With .equals() No match");

      }

      

      // Prints string out one char at a time

      char[] chars = s1.toCharArray();

      for (char c : chars) {

            System.out.println(c);

      }

    }

 

}

 

 

String Builder vs String Buffer

• Builder - single thread
• Buffer - multi threaded

 

Code:

public class Main {

 

    public static void main(String[] args) {

      String s1 = "Welcome";

      StringBuilder sb = new StringBuilder(s1);

      

      sb.append(" to California");

      System.out.println(sb);

      //string builder vs string buffer

      

    }

 

}

 

 

String Manipulation

 

Code:

public class Main {

 

    public static void main(String[] args) {

      

      String s1 = ("Welcome to California!");

      System.out.println("Length of string: " + s1.length());

      

      //String position

      int pos = s1.indexOf("California");

      System.out.println("Position of California: " + pos);

      

      // SubStrings

      String sub = s1.substring(11);

      System.out.println(sub);

      

      //

      String s2 = "Welcome!     ";

      int len1 = s2.length();

      System.out.println(len1);

      String s3 = s2.trim();

      System.out.println(s3.length());

      

      

      

    }

 

}

 

 

Date Manipulation

Code:

import java.text.DateFormat;

import java.util.Date;

import java.util.GregorianCalendar;

 

 

public class Main {

 

    public static void main(String[] args) {

      Date d = new Date();

      System.out.println(d);

      //Fri Aug 03 17:43:06 CDT 2012

      

      //Date class that can add days to, etc

      GregorianCalendar gc = new GregorianCalendar(2009, 1, 28);

      System.out.println(gc);

      //java.util.GregorianCalendar[time=1235887200000,areFieldsSet=true,areAllFieldsSet=true,lenient=true,zone=sun.util.calendar.ZoneInfo[id="America/Chicago",offset=-21600000,dstSavings=3600000,useDaylight=true,transitions=235,lastRule=java.util.SimpleTimeZone[id=America/Chicago,offset=-21600000,dstSavings=3600000,useDaylight=true,startYear=0,startMode=3,startMonth=2,startDay=8,startDayOfWeek=1,startTime=7200000,startTimeMode=0,endMode=3,endMonth=10,endDay=1,endDayOfWeek=1,endTime=7200000,endTimeMode=0]],firstDayOfWeek=1,minimalDaysInFirstWeek=1,ERA=1,YEAR=2009,MONTH=2,WEEK_OF_YEAR=10,WEEK_OF_MONTH=1,DAY_OF_MONTH=1,DAY_OF_YEAR=60,DAY_OF_WEEK=1,DAY_OF_WEEK_IN_MONTH=1,AM_PM=0,HOUR=0,HOUR_OF_DAY=0,MINUTE=0,SECOND=0,MILLISECOND=0,ZONE_OFFSET=-21600000,DST_OFFSET=0]

      //need to prep for printing....

      

      //add gc field (YEAR/MONTH/DATE), add by how much

      gc.add(GregorianCalendar.DATE, 1);

 

      //prep for printing

      Date d2 = gc.getTime();

      System.out.println(d2);

      //Sun Mar 01 00:00:00 CST 2009

      

      //factoring method, returns an instance of that class

      DateFormat df = DateFormat.getDateInstance();

      String sd = df.format(d2);

      System.out.println(sd);

      //Mar 1, 2009

 

      // can format the Date object in many ways..

      DateFormat df2 = DateFormat.getDateInstance(DateFormat.FULL);

      String sd2 = df2.format(d2);

      System.out.println(sd2);

      //Sunday, March 1, 2009

      

    }

 

}