Conversion between string and date, timestamp in Java _java

One, string and Date (java.util.Date) interchange

1.1 String-> Date

String datestr = "//::";  
    Date date = new Date ();  
   Note format must match the format of date string  
   dateformat sdf = new SimpleDateFormat ("Yyyy/mm/dd HH:mm:ss");  
   try {  
     date = Sdf.parse (DATESTR);  
      System.out.println (Date.tostring ());  
    } catch (Exception e) {  
      e.printstacktrace ();  
    } 
 String datestr = "2010/05/04 12:34:23";
 Date date = new Date ();
 Note format must match the format of date string
 dateformat sdf = new SimpleDateFormat ("Yyyy/mm/dd HH:mm:ss");
 try {
  date = Sdf.parse (DATESTR);
  System.out.println (Date.tostring ());
 } catch (Exception e) {
  e.printstacktrace ();
 

1.2 Date-> String

Date to string conversion, you can set any conversion format

String datestr = "";  
   Date date = new Date ();  
   Format can be arbitrary  
    dateformat sdf = new SimpleDateFormat ("Yyyy/mm/dd HH:mm:ss");  
   DateFormat SDF = new SimpleDateFormat ("Yyyy-mm-dd hh/mm/ss");  
    try {  
      datestr = Sdf.format (date);  
     System.out.println (DATESTR);  
      Datestr = Sdf.format (date);  
      System.out.println (DATESTR);  
    } catch (Exception e) {  
      e.printstacktrace ();  
    } 
 String datestr = "";
 Date date = new Date ();
 Format can be arbitrary
 dateformat sdf = new SimpleDateFormat ("Yyyy/mm/dd HH:mm:ss");
 DateFormat sdf2 = new SimpleDateFormat ("Yyyy-mm-dd hh/mm/ss");
 try {
  datestr = Sdf.format (date);
  System.out.println (DATESTR);
  Datestr = Sdf2.format (date);
  System.out.println (DATESTR);
 } catch (Exception e) {
  e.printstacktrace ();
 

Two, string and timestamp mutual turn

2.1 String->timestamp

Using the timestamp valueof () method

Timestamp ts = new Timestamp (System.currenttimemillis ());  
    String tsstr = "--::";  
     try {  
       ts = timestamp.valueof (TSSTR);  
       SYSTEM.OUT.PRINTLN (TS);  
    } catch (Exception e) {  
      e.printstacktrace ();  
    } 
 Timestamp ts = new Timestamp (System.currenttimemillis ());
 String tsstr = "2011-05-09 11:49:45";
 try {
  ts = timestamp.valueof (TSSTR);
  SYSTEM.OUT.PRINTLN (TS);
 } catch (Exception e) {
  e.printstacktrace ();
 

Note: String must be of type such as: Yyyy-mm-dd hh:mm:ss[.f ...] in this format, brackets indicate optional, otherwise the error is!!!

If the string is in another format, consider parsing the string again, and then reorganizing ~ ~

2.2 Timestamp-> String

Use Timestamp's ToString () method or borrow DateFormat

Timestamp ts = new Timestamp (System.currenttimemillis ());  
    String tsstr = "";  
    DateFormat SDF = new SimpleDateFormat ("Yyyy/mm/dd HH:mm:ss");  
    try {  
      //method one  
      tsstr = Sdf.format (ts);  
     System.out.println (TSSTR);  
     Method two  
    tsstr = ts.tostring ();  
      System.out.println (TSSTR);  
    } catch (Exception e) {  
     e.printstacktrace ();  
   } 
 Timestamp ts = new Timestamp (System.currenttimemillis ());
 String tsstr = "";
 DateFormat SDF = new SimpleDateFormat ("Yyyy/mm/dd HH:mm:ss");
 try {
  //method one
  tsstr = Sdf.format (ts);
  System.out.println (TSSTR);
  Method two
  tsstr = ts.tostring ();
  System.out.println (TSSTR);
 } catch (Exception e) {
  e.printstacktrace ();
 

It is easy to see that the advantage of method one is that it is flexible to set the form of a string.

Iii. Date (java.util.Date) and timestamp interchange

Statement: Check API, date and Timesta are parent-child relationships

3.1 Timestamp-> Date

Timestamp ts = new Timestamp (System.currenttimemillis ());  
   Date date = new Date ();  
   try {  
     date = ts;  
      SYSTEM.OUT.PRINTLN (date);  
    catch (Exception e) {  
     e.printstacktrace ();  
    } 
 Timestamp ts = new Timestamp (System.currenttimemillis ());
 Date date = new Date ();
 try {
  date = ts;
  SYSTEM.OUT.PRINTLN (date);
 catch (Exception e) {
  e.printstacktrace ();
 }

Very simple, but at the moment the date object points to an entity that is a timestamp, that is, date has a method of the date class, but the executing entity of the overridden method is in timestamp.

3.2 Date-> Timestamp

The parent class cannot be directly converted to subclasses, with the help of the middle string~~~~

Java.sql.Date only store date data does not store time data
//will lose time Data
preparedstatement.setdate (1, New Java.sql.Date (Date.gettime ()));
This can be done with
Preparedstatement.settimestamp (1, New Java.sql.Timestamp (New Java.util.Date (). GetTime ()));
 Want to get complete data, including date and time, you can do so
java.util.Date d = resultset.gettimestamp (1);
This is a more appropriate process to avoid some potential timestamp problems
java.util.Date d = new Java.util.Date (Resultset.gettimestamp (1). GetTime ());

Make up your own words, such words:

When storing to the database, you can receive the Java.util.Date type and then use the GetTime () method to get a long value representing that date object, and then construct a timestamp object into the database with this long value.

When you take it from a stored database, you can get timestamp to use his gettime () method to get a long value and then construct a Java.util.Date object with this long value so that you can manipulate the date object. It's better to say new Simpletimeformat ("Yyyyy-mm-dd HH:mm:ss"). Format () and so on