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Articles by karthikeya Boyini
Page 128 of 143
As HTTP is a stateless then how to maintain the session between web browser and web server?
HTTP is a "stateless" protocol which means each time a client retrieves a Webpage, the client opens a separate connection to the Web server and the server automatically does not keep any record of previous client request.Maintaining Session Between Web Client And ServerLet us now discuss a few options to maintain the session between the Web Client and the Web Server −CookiesA webserver can assign a unique session ID as a cookie to each web client and for subsequent requests from the client they can be recognized using the received cookie.This may not be an effective way as the browser ...
Read MoreInsert default into not null column if value is null in MySQL?
You can use IFNULL() property or simple IF() with IS NULL property. The syntax is as follows −INSERT INTO yourTableName(yourColumnName1, yourColumnName2) VALUES('yourValue’', IF(yourColumnName1 IS NULL, DEFAULT(yourColumnName2), 'yourMessage'));To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table Post -> ( -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> UserName varchar(10), -> UserPostMessage varchar(50) NOT NULL DEFAULT 'Hi Good Morning !!!' -> ); Query OK, 0 rows affected (0.67 sec)Now you can ...
Read MoreCreate Pair Tuple from another collection in Java
Use the fromCollection() method to create a Pair Tuple from another collection, for example, List.Let us first see what we need to work with JavaTuples. To work with Pair class in JavaTuples, you need to import the following package −import org.javatuples.Pair;Note − Steps to download and run JavaTuples program If you are using Eclipse IDE to run Pair Class in JavaTuples, then Right Click Project → Properties → Java Build Path → Add External Jars and upload the downloaded JavaTuples jar file.The following is an example −Exampleimport org.javatuples.Pair; import java.util.*; public class Demo { public static void main(String[] args) ...
Read MoreHow to disable "Establishing SSL connection without server's identity verification is not recommended" warning when connecting to MySQL database in Java?
To disable the warning while connecting to a database in Java, use the below concept −autoReconnect=true&useSSL=falseThe complete syntax is as follows −yourJdbcURL="jdbc:mysql://localhost:yourPortNumber/yourDatabaseName?autoReconnect=true&useSSL=false";Here is the warning message if you do not include “useSSL=false” −Wed Feb 06 18:53:39 IST 2019 WARN: Establishing SSL connection without server's identity verification is not recommended. According to MySQL 5.5.45+, 5.6.26+ and 5.7.6+ requirements SSL connection must be established by default if explicit option isn't set. For compliance with existing applications not using SSL the verifyServerCertificate property is set to 'false'. You need either to explicitly disable SSL by setting useSSL=false, or set useSSL=true and provide truststore ...
Read MoreJavaTuples setAt0() method for Quintet class
The setAt0() method is used to set the Quintet value in JavaTuples and a copy with a new value at the specified index i.e. index 0 here.Let us first see what we need to work with JavaTuples. To work with Quintet class in JavaTuples, you need to import the following package −import org.javatuples.Quintet;Note − Steps to download and run JavaTuples program If you are using Eclipse IDE to run Quintet Class in JavaTuples, then Right Click Project → Properties → Java Build Path → Add External Jars and upload the downloaded JavaTuples jar file.The following is an example −Exampleimport org.javatuples.Quintet; ...
Read MoreJava Tuples addAtX() method for Pair class
The addAtX() method is used to add value at a particular position represented by X here.Let us first see what we need to work with JavaTuples. To work with Pair class in JavaTuples, you need to import the following package −import org.javatuples.Pair;Here we have also used the Triplet class, therefore import the following package −import org.javatuples.Triplet;Note − Steps to download and run JavaTuples program If you are using Eclipse IDE to run Pair Class in JavaTuples, then Right Click Project → Properties → Java Build Path → Add External Jars and upload the downloaded JavaTuples jar file.The following is an ...
Read MoreIs RowSet Scrollable? Explain with an example?
A RowSet object is similar to ResultSet, it also stores tabular data, in addition to the features of a ResultSet. A RowSet follows the JavaBeans component model.If you Retrieve a ResultSet object by default the cursor of it moves only in forward direction. i.e. you can retrieve the contents of it from first to last.But, in a scrollable result set, the cursor can scroll forward and backward and you can retrieve data backward too.To make ResultSet object scrollable, you need to create one as shown below −Statement stmt = con.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_UPDATABLE);Whereas, a RowSet object is Scrollable by default. Therefore, whenever ...
Read MoreJava Program to create custom DateTime formatter
To create custom DateTime formatter, use DateTimeFormatter. Let us first see for Time −DateTimeFormatter dtFormat = new DateTimeFormatterBuilder() .appendValue(ChronoField.HOUR_OF_DAY) .appendLiteral(":") .appendValue(ChronoField.MINUTE_OF_HOUR) .appendLiteral(":") .appendValue(ChronoField.SECOND_OF_MINUTE) .toFormatter();For Date −dtFormat = new DateTimeFormatterBuilder() .appendValue(ChronoField.YEAR) .appendLiteral("/") .appendValue(ChronoField.MONTH_OF_YEAR) .appendLiteral("/") .appendValue(ChronoField.DAY_OF_MONTH) .toFormatter();Exampleimport java.time.LocalDateTime; import java.time.format.DateTimeFormatter; import java.time.format.DateTimeFormatterBuilder; import java.time.temporal.ChronoField; public class Demo { public static void main(String[] args) { DateTimeFormatter dtFormat = new DateTimeFormatterBuilder() .appendValue(ChronoField.HOUR_OF_DAY) .appendLiteral(":") .appendValue(ChronoField.MINUTE_OF_HOUR) .appendLiteral(":") .appendValue(ChronoField.SECOND_OF_MINUTE) .toFormatter(); System.out.println("Time = "+dtFormat.format(LocalDateTime.now())); dtFormat = new DateTimeFormatterBuilder() ...
Read MoreCreate Quintet Tuple from another collection in Java
To create a tuple from another collection, you need to use fromCollection() method.Let us first see what we need to work with JavaTuples. To work with Quintet class in JavaTuples, you need to import the following package −import org.javatuples.Quintet;Note − Steps to download and run JavaTuples program If you are using Eclipse IDE to run Quintet Class in JavaTuples, then Right Click Project → Properties → Java Build Path → Add External Jars and upload the downloaded JavaTuples jar file.The following is an example −Exampleimport org.javatuples.Quintet; import java.util.*; public class Demo { public static void main(String[] args) { ...
Read MoreHow to insert data into a CachedRowSet in JDBC? Explain?
The CachedRowSet is the base implementation of disconnected row sets. It connects to the data source, reads data from it, disconnects with the data source and the processes the retrieved data, reconnects to the data source and writes the modifications.Creating a CachedRowSetYou can create a Cached RowSet object using the createCachedRowSet() method of the RowSetFactory.You can create a RowSetFactory object using the newfactory() method of the RowSetProvider method.Create a CachedRowSet object using the above mentioned methods as shown below −//Creating the RowSet object RowSetFactory factory = RowSetProvider.newFactory(); CachedRowSet rowSet = factory.createCachedRowSet();Connecting to the data sourceAfter creating a RowSet object you ...
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