How To Convert Timestamp To Appointment Inwards Coffee -Jdbc Example Tutorial

In the final article, I receive got shown you lot how to convert Date to Timestamp inwards Java as well as today we'll acquire nigh converting timestamp value from database to Date inwards Java. As you lot remember, the JDBC API uses split Date, Time as well as Timestamp shape to confirm DATE, TIME as well as DATETIME information type from the database, but most of the Java object oriented code is written inwards java.util.Date. This agency you lot demand to know how to convert the timestamp to appointment as well as vice-versa. You tin sack exercise past times using the getTime() method, which furnish the publish of millisecond from Epoch value. This tin sack last used to exercise both Timestamp as well as java.util.Date, hence it acts as a span betwixt Date shape from java.util parcel as well as Date, Time as well as Timestamp shape from the java.sql package. Like Date, Timestamp besides contains both appointment as well as fourth dimension value, then you lot won't come across empty or null fourth dimension nosotros saw previously piece converting SQL Date to java.util.Date.

As I receive got said before, fifty-fifty though classes from java.sql parcel extends java.util.Date, including Timestamp they cannot last used inwards house of java.util.Date. Some of you lot may enquire why? Since Timestamp has both appointment as well as fourth dimension value, it should last able to acts every bit Date, nosotros empathise nigh java.sql.Date non having fourth dimension gene but amongst Timestamp nosotros receive got both.

Well, that's in 1 lawsuit to a greater extent than a really expert reasoning as well as directs your heed to detect the missing business office of why you lot cannot role Timestamp inwards house of date fifty-fifty if it has both appointment as well as fourth dimension part. The response lies inwards the Java documentation itself. The Timestamp shape is a composite of java.util.Date as well as an additional nanoseconds values, required to check the SQL TIMESTAMP fractional seconds value. If you lot aspect at the implementation of Timestamp class, you lot volition detect that exclusively integral seconds are stored inwards the java.util.Date component. The fractional seconds - the nanos - are separate.



The Timestamp.equals(Object) method never returns truthful when passed an object that isn't an instance of java.sql.Timestamp e.g. Timestamp.equals(date) volition furnish false fifty-fifty if they comprise same value because the nanos gene of a appointment is unknown. As a result, the Timestamp.equals(Object) method is not symmetric amongst abide by to the java.util.Date.equals(Object) method, hence it besides violates the contract of equals method. Also, the hashCode method uses the underlying java.util.Date implementation as well as thence does non include nanos inwards its computation.

Btw, If you lot desire to refresh your concepts of equals as well as hashcode, I advise you lot reading Effective Java, where Joshua Bloch has discussed it inwards slap-up detail.

So fifty-fifty though, methods similar getHours(), getMinutes(), getSeconds() doesn't throw IllegalArgumentException, because of these differences, you lot withal should non role a Timestamp value inwards house of java.util.Date. The inheritance human relationship betwixt Timestamp as well as java.util.Date actually denotes implementation inheritance, as well as non type inheritance.

Java Program to convert Timestamp to Date amongst example

Now, let's come across our sample Java programme to convert a Timestamp value to Date inwards Java. In this example, our Java programme connects to the Microsoft SQL server as well as telephone phone the CURRENT_TIMESTAMP method using PreparedStatment object. This method returns the electrical flow database organization timestamp every bit a DATETIME value withtout the database fourth dimension zone offsert. This value is derived from the operating sytsem of the figurer on which the instance of SQL Server is running (see SQL fundamentals).

When nosotros read this value inwards Java using ResultSet, nosotros role the getTimestamp() method as well as transcend it the column index. If you lot remember, columns inwards JDBC API starts amongst 1 instead of zero, nosotros transcend 1. We besides demand to telephone phone the next() method of ResultSet to motion the cursor to the start element, otherwise you lot won't the right value. Once you lot got the java.sql.Timestamp value, merely telephone phone the getTime() as well as exercise a java.util.Date instnace using that. Now, you lot receive got successfully converted a java.sql.Timestamp value to java.util.Date value.

Program to convert Timestamp to Date inwards Java

import java.io.PrintWriter; import java.sql.Connection; import java.sql.DriverManager; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.Timestamp; import java.util.Date;  /*  * Java Program to convert Timestamp to Date inwards JDBC.  */  public class Pattern {    public static void main(String[] args) {      Timestamp timestamp = timeStampFromDatabase();     Date appointment = new java.util.Date(timestamp.getTime());     System.out.println("current timestamp from database: " + timestamp);     System.out.println("converted appointment inwards Java: " + date);    }    public static Timestamp timeStampFromDatabase() {     Connection con = null;     Timestamp currentTimeStamp = null;     try {       Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");       String url = "jdbc:sqlserver://localhost:42588;";       DriverManager.setLogWriter(new PrintWriter(System.out, true));       con = DriverManager.getConnection(url, "sa", "root");        PreparedStatement ps = con.prepareStatement("select CURRENT_TIMESTAMP");       ResultSet rs = ps.executeQuery();        rs.next(); // motion the cursor to start column       currentTimeStamp = rs.getTimestamp(1);      } catch (Exception e) {       e.printStackTrace();     }     return currentTimeStamp;   }  }  Output DriverManager.getConnection("jdbc:sqlserver://localhost:42588;") trying sun.jdbc.odbc.JdbcOdbcDriver *Driver.connect (jdbc:sqlserver://localhost:42588;) trying com.microsoft.sqlserver.jdbc.SQLServerDriver getConnection returning com.microsoft.sqlserver.jdbc.SQLServerDriver electrical flow timestamp from database: 2016-06-17 13:13:56.61 converted appointment in Java: Friday Jun 17 13:13:56 PST 2016

Influenza A virus subtype H5N1 span of of import things to acquire inwards this program, first, I receive got non called the Class.forName() method to explicitly charge the JDBC driver because from Java 1.6 onward, it tin sack last automatically loaded past times JVM. The minute of import affair is the role of setting the logger for DriverManager, which volition impress of import details e.g. which JDBC driver it is loading as well as which host as well as port it is connecting to database.

The code to convert Timestamp into a java.util.Date is within main() method, you lot tin sack come across it's quite simple, merely receive got the long millisecond value past times calling getTime() on Timestamp as well as transcend it to Date constructor, that's it, you lot are done.

You tin sack farther read Core Java, Volume II--Advanced Features past times Cay S. Horstmann to acquire to a greater extent than nigh JDBC driver as well as other JDBC concepts, 1 of the most useful books to acquire Java concepts.

Important points

- Timestamp shape has both appointment as well as fourth dimension value every bit Date but cannot last used inwards house of java.util.Date becaues of additional nanosecond value it supports.

- The Timestamp.equals(Object) method volition furnish false if you lot compare Timestamp amongst Date, this is 1 of the reasons you cannot role Timestamp inwards house of Date inwards Java.

- The Timestamp shape has "s" instead of "S" which you lot powerfulness aspect given most of the Java classes are written using Camel case. Another 1 is Hashtable amongst "t" intead of "T"

- Columns are started amongst index 1 instead of null hence getTimestamp(1) is used. This is non merely related to Timestamp but related to ResultSet inwards JDBC as well as you lot must retrieve this to avoid java.sql.SQLException: invalid column index, which oftentimes comes when a programmer tries to access the start column amongst index zero, which is invalid.

- Don't forget to telephone phone ResultSet.next() method earlier calling get() fifty-fifty if it contains merely 1 row. It is required to motion the cursor to start element. It's a tricky concept to master copy but if you lot don't know the right way to cheque if ResultSet is empty or not, you lot volition grapple to write robust JDBC code inwards future.


That's all nigh how to convert a Timestamp to Date inwards Java. As a programmer working amongst Java, JDBC as well as database you lot must know these details nigh Timestamp as well as Date class, its imperative to write right JDBC code. Unfortunately, Java could receive got done ameliorate undertaking past times standaring things, every bit it's a drawback of an API, if programmer needs to retrieve then many special cases.

Further Learning
Complete Java Masterclass
Java Fundamentals: The Java Language
Java In-Depth: Become a Complete Java Engineer!