String concatenation, truncation, search, and date conversion

Import java. util. Date;
Public class JavaString {
 
/**
* @ Param args
*/
Public static void main (String [] args ){
// TODO Auto-generated method stub
// Char to string
Char a [] = {'G', 'O', 'O', 'D ','.'};
String s = new String (a); // All characters
System. out. println (s );
String ss = new String (a, 2, 2); // some characters
System. out. println (ss );
// Connect multiple strings
String s1 = new String ("Hello ");
String s2 = new String ("World ");
String sss = s1 + "" + s2;
System. out. println (sss );
// Connect other data types, int and float
Int booktime = 4;
Float practice = 2.5f;
System. out. println ("I spent" + booktime + "hours reading books;" + practice + "hours on-board exercises .");
// String str = String. format ("I spent {1} hours reading a book every day; {2} hours on-board exercises.", booktime, practice );
// System. out. println (str );
// Obtain the string length:
String str = "We are studentsa ";
Int size = str. length ();
System. out. println ("str. length () =" + size );
// String SEARCH:
Int size1 = str. indexOf ("");
System. out. println ("string SEARCH indexOf (a):" + size1 );
Int size2 = str. lastIndexOf ("");
System. out. println ("string SEARCH: lastIndexOf (a)" + size2 );
// Search for an empty string:
Int size3 = str. indexOf (""); // int size3 = str. indexOf ("");
System. out. println ("null string location:" + size3 );
// Obtain the sub-string: // beginIndex <= endIndex
String substr = str. substring (3, 4); // String substr = str. substring (3 );
System. out. println ("Get substring:" + substr );
// Remove spaces:
String javaStr = "Java Class ";
System. out. println ("original String length:" + javaStr. length ());
System. out. println ("length of the string after spaces are removed:" + javaStr. trim (). length ());
// String replacement
String address = "address ";
String newstr = address. replace ("a", "");
System. out. println (newstr );
// Judge the start and end of a string:
String num1 = "22045612 ";
String num2 = "21304578 ";
Boolean B = num1.startsWith ("22 ");
Boolean b2 = num1.endsWith ("78 ");
Boolean b3 = num2.startsWith ("22 ");
Boolean b4 = num2.endsWith ("78 ");
System. out. println ("does the string num1 start with '22? "+ B );
System. out. println ("is the string num1 ending with '78? "+ B2 );
System. out. println ("does the string num1 start with '22? "+ B3 );
System. out. println ("is the string num1 ending with '78? "+ B4 );
// Judge whether the string is equal
String tom = new String ("I am ");
String jerry = new String ("I am ");
Boolean bb = (tom = jerry );
Boolean bbb = tom. equals (jerry); // specify signorecase
System. out. println ("tom = jerry:" + bb );
System. out. println ("tom. equals (jerry):" + bbb );
// Case-insensitive conversion:
String mystr = new String ("abc DEF ");
String newstrs = mystr. toLowerCase ();
String newstrs2 = mystr. toUpperCase ();
System. out. println (newstrs );
System. out. println (newstrs2 );
// String segmentation:
String splitStr = new String ("abc, def, ghi, gkl ");
String [] newsplitstr = splitStr. split (",");
For (int I = 0; I <newsplitstr. length; I ++)
{
System. out. println (newsplitstr [I]);
}
String [] newsplitstr2 = splitStr. split (",", 2); // you can specify the number of splits.
For (int I = 0; I <newsplitstr2.length; I ++)
{
System. out. println (newsplitstr2 [I]);
}
// Format the string:
// Format the date
// % Te a day in a month (1-31)
// % Tb month
// Full name of % tB month
// % TA full name of the day of the week
// % Ta day of the week
// % Tc
// % TY 4-digit year (2009)
// % The day of the tj year (001-366)
// % Tm month
// % Td the day of the month (01-31)
// % Ty 2-digit year
Date date = new Date ();
String dates = String. format ("% te", date );
String datedays = String. format ("% tj", date );
System. out. println ("Date:" + dates );
System. out. println ("day of the year:" + datedays );
// Time format:
// % TH 2-digit 24 hours: (00-23)
// % TI 2-digit 12 hours: (01-12)
// % Tk 2-digit 24 hours: (0-23)
// % Tl 2-digit 12 hours: (1-12)
// % TM 2-digit minute (00-59)
// % TS 2-digit second (00-60)
// % TL 8-bit Millisecond (000-999)
// % TN 9-bit Millisecond ()
// % Tp upper afternoon,
// % Tz
// % TZ
// % Ts 1970-01-01 00:00:00 seconds passed so far
// % TQ 00:00:00 milliseconds passed so far
String hour = String. format ("% tH", date );
String minute = String. format ("% tM", date );
String second = String. format ("% tS", date );
String msecond = String. format ("% tQ", date );
System. out. println ("now" + hour + "" + minute + "minute" + second + "second ");
System. out. println ("now in milliseconds:" + msecond );
// Date and Time combination:
// % TF year-month-day
// % TD month/day/year
// % Tc all date and time information
// % Tr minutes and seconds last afternoon
// % TT hour/minute/second
// % TR time
String time = String. format ("% tc", date );
String form = String. format ("% tF", date );
String sfm = String. format ("% tT", date );
System. out. println ("all time information:" + time );
System. out. println ("year-month-day format:" + form );
System. out. println ("hour/minute/Second:" + sfm );
System. out. println ("date. toString ():" + date. toString (); // date. toLocaleString ()
System. out. println ("date. toLocaleString ():" + date. toLocaleString ());
// Use a regular expression
// String builder: StringBuilder
// Builder. append (); insert (int offset arg); delete (int start, int end );
StringBuilder bf = new StringBuilder ("Hello ");
Bf. insert (5, "word ");
System. out. println (bf. toString ());
}
 
}

Author: ERDP Technical Architecture"