| Types java app |
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| Data Types and Operators |
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| (Primitive Data Types) |
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| (Non-Primitive Data Types) |
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| Control Flow Statements |
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| Conditional Statements |
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| Looping Statements |
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| Branching Statements |
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| Object-Oriented Programming (OOP) |
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| Classes and Objects |
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| Inheritance |
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| Polymorphism |
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| Encapsulation |
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| Abstraction |
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| Exception Handling |
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| Introduction to Exceptions |
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| Collections Framework |
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| Overview of Collections |
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| Commonly Used Collections |
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| Iterators |
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| Java I/O |
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| File Handling |
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| Serialization |
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| Multithreading |
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| Introduction to Threads |
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| Thread Synchronization |
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| GUI Programming with Swing |
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| Introduction to Swing |
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| Event Handling |
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| Advanced Topics |
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| Java Database Connectivity (JDBC) |
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| JAVA CODE |
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Java Basics
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Working with Objects
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Arrays, Conditionals, and Loops
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Creating Classes and Applications in Java
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More About Methods
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Java Applet Basics
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Graphics, Fonts, and Color
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Simple Animation and Threads
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More Animation, Images, and Sound
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Managing Simple Events and Interactivity
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Creating User Interfaces with the awt
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Windows, Networking, and Other Tidbits
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Modifiers, Access Control, and Class Design
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Packages and Interfaces
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Exceptions
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Multithreading
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Streams and I/O
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Using Native Methods and Libraries
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Under the Hood
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Java Programming Tools
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Working with Data Structures in Java
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Advanced Animation and Media
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Fun with Image Filters
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Client/Server Networking in Java
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Emerging Technologies
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appendix A :- Language Summary
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appendix B :- Class Hierarchy Diagrams
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appendix C The Java Class Library
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appendix D Bytecodes Reference
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appendix E java.applet Package Reference
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appendix F java.awt Package Reference
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appendix G java.awt.image Package Reference
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appendix H java.awt.peer Package Reference
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appendix I java.io Package Reference
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appendix J java.lang Package Reference
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appendix K java.net Package Reference
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appendix L java.util Package Reference
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In Java, JDBC (Java Database Connectivity) is an API that allows Java applications to interact with databases. Two important components of JDBC are ‘ResultSet‘ and ‘PreparedStatement‘. Let’s dive deeper into each with detailed descriptions and examples.
PreparedStatement
Description
PreparedStatement is an interface in the java.sql package. It extends the Statement interface and provides a more efficient and secure way to execute SQL queries. The primary advantages of using PreparedStatement are:
- Pre-compilation: SQL queries are pre-compiled and stored in a
PreparedStatementobject. This can improve performance, especially when executing the same query multiple times. - Prevention of SQL Injection: By using placeholders (
?) in SQL statements and setting parameter values through methods,PreparedStatementhelps prevent SQL injection attacks. - Parameter Binding: Allows binding of parameters to placeholders, making it easier to handle SQL queries with varying parameters.
Example
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
public class PreparedStatementExample {
public static void main(String[] args) {
String jdbcURL = "jdbc:mysql://localhost:3306/mydatabase";
String username = "root";
String password = "password";
Connection connection = null;
PreparedStatement preparedStatement = null;
ResultSet resultSet = null;
try {
// Establishing a connection
connection = DriverManager.getConnection(jdbcURL, username, password);
// SQL query with placeholders
String sql = "SELECT * FROM users WHERE username = ? AND password = ?";
// Creating PreparedStatement object
preparedStatement = connection.prepareStatement(sql);
preparedStatement.setString(1, "john_doe"); // Setting the first parameter
preparedStatement.setString(2, "secret123"); // Setting the second parameter
// Executing the query
resultSet = preparedStatement.executeQuery();
// Processing the ResultSet
while (resultSet.next()) {
int id = resultSet.getInt("id");
String usernameDB = resultSet.getString("username");
String passwordDB = resultSet.getString("password");
System.out.println("ID: " + id + ", Username: " + usernameDB + ", Password: " + passwordDB);
}
} catch (SQLException e) {
e.printStackTrace();
} finally {
// Closing resources
try {
if (resultSet != null) resultSet.close();
if (preparedStatement != null) preparedStatement.close();
if (connection != null) connection.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
}
ResultSet
Description
‘ResultSet‘ is an interface in the ‘java.sql‘ package that represents the result set of a database query. It is used to retrieve and manipulate the data returned by the SQL query. The ResultSet object maintains a cursor pointing to its current row of data. Initially, the cursor is positioned before the first row. The ‘next()‘ method moves the cursor to the next row.
Example
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
public class ResultSetExample {
public static void main(String[] args) {
String jdbcURL = "jdbc:mysql://localhost:3306/mydatabase";
String username = "root";
String password = "password";
Connection connection = null;
PreparedStatement preparedStatement = null;
ResultSet resultSet = null;
try {
// Establishing a connection
connection = DriverManager.getConnection(jdbcURL, username, password);
// SQL query
String sql = "SELECT * FROM users";
// Creating PreparedStatement object
preparedStatement = connection.prepareStatement(sql);
// Executing the query
resultSet = preparedStatement.executeQuery();
// Processing the ResultSet
while (resultSet.next()) {
int id = resultSet.getInt("id");
String usernameDB = resultSet.getString("username");
String passwordDB = resultSet.getString("password");
System.out.println("ID: " + id + ", Username: " + usernameDB + ", Password: " + passwordDB);
}
} catch (SQLException e) {
e.printStackTrace();
} finally {
// Closing resources
try {
if (resultSet != null) resultSet.close();
if (preparedStatement != null) preparedStatement.close();
if (connection != null) connection.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
}
Key Methods
PreparedStatement Methods
setString(int parameterIndex, String x): Sets the designated parameter to the given JavaStringvalue.setInt(int parameterIndex, int x): Sets the designated parameter to the given Javaintvalue.executeQuery(): Executes the SQL query in thisPreparedStatementobject and returns aResultSetobject.executeUpdate(): Executes the SQL statement in thisPreparedStatementobject, which must be an SQL Data Manipulation Language (DML) statement, and returns the number of affected rows
ResultSet Methods
next(): Moves the cursor to the next row.getInt(String columnLabel): Retrieves the value of the designated column as anint.getString(String columnLabel): Retrieves the value of the designated column as aString.close(): Releases thisResultSetobject’s database and JDBC resources immediately.
