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@jonathanvila
Created April 25, 2024 17:06
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DBUtils no SonarLint
package demo.security.util;
import demo.security.servlet.FileServlet;
import javax.naming.AuthenticationException;
import java.io.Serializable;
import java.sql.*;
import java.util.*;
import java.util.concurrent.ThreadFactory;
import java.util.stream.Collectors;
public class DBUtils {
Object value;
Connection connection;
/**
* The following code shows how to use {@code Optional.isPresent}:
* {@snippet :
* if (v.isPresent()) { // @highlight substring="isPresent"
* System.out.println("v: " + v.get());
* }
*}
* Where v != null
*/
public boolean isPresent() {
return value != null;
}
public DBUtils() throws SQLException {
connection = DriverManager.getConnection(
"mYJDBCUrl", "myJDBCUser", "myJDBCPasswd");
ArrayList<String> list = new ArrayList<>();
list.add("hola");
for (var it = list.listIterator(list.size()); it.hasPrevious();) {
var element = it.previous();
System.out.println(element);
}
}
public void newConnect() throws SQLException {
connection = DriverManager.getConnection(
"mYJDBCUrl", "myJDBCUser", "myJDBCPasswd");
ArrayList<String> list = new ArrayList<>();
list.add("hola");
for (var it = list.listIterator(list.size()); it.hasPrevious();) {
var element = it.previous();
System.out.println(element);
}
}
public List<String> findUsers(String user) throws Exception {
String query = "SELECT userid FROM users WHERE username = '" + user + "'";
Statement statement = connection.createStatement();
ResultSet resultSet = statement.executeQuery(query);
List<String> users = new ArrayList<String>();
while (resultSet.next()) {
users.add(resultSet.getString(0));
}
sumNumbers(100);
return users;
}
public List<String> findItem(String itemId) throws Exception {
String query = "SELECT item_id FROM items WHERE item_id = '" + itemId + "'";
Statement statement = connection.createStatement();
ResultSet resultSet = statement.executeQuery(query);
List<String> items = new ArrayList<String>();
while (resultSet.next()) {
items.add(resultSet.getString(0));
}
return items;
}
public void sumNumbers(int max) {
int count, sum = 0;
for (int number = 1; number <= max; number++) {
count = 0;
for (int i = 2; i <= number / 2; i++) {
if (number % i == 0) {
count++;
break;
}
}
if (count == 0 && number != 1) {
sum = sum + number;
}
}
System.out.println("The Sum of numbers is: " + sum);
}
public void threads() {
Thread.Builder.OfVirtual virtual = Thread.ofVirtual();
var thread = virtual.start(() -> {
var a=10;
System.out.println(a);
});
thread.setDaemon(false);
thread.setPriority(10);
thread.getThreadGroup();
System.out.print(thread.getName());
Runnable printThread = () -> System.out.println(Thread.currentThread());
Thread virtualThread = Thread.ofVirtual().factory().newThread(printThread);
ThreadFactory kernelThreadFactory = Thread.ofPlatform().factory();
Thread kernelThread = kernelThreadFactory.newThread(printThread);
virtualThread.setPriority(Thread.MIN_PRIORITY);
virtualThread.start();
kernelThread.start();
var kernelThread3 = new Thread(printThread);
kernelThread3.setPriority(0);
kernelThread3.setDaemon(false);
System.out.println(STR."Group:\{kernelThread3.getThreadGroup()}");
kernelThread3.start();
}
String guardedCaseSwitch(Object obj) {
return switch (obj) {
case String s when !s.isEmpty() -> String.format("String %s", s);
case Integer i when i > 0 -> String.format("int %d", i);
default -> obj.toString();
};
}
public double calculateAverage(Collection<Integer> collection) {
int suma= 10;
int sum = 0;
for (Integer num : collection) {
sum += num;
}
return (double) sum / collection.size();
}
public double calculateAverageManual(Collection<Integer> collection) {
int suma = 10;
return collection.stream().collect(Collectors.teeing(
Collectors.summingDouble(i -> i),
Collectors.counting(),
(sum, count) -> sum / count));
}
}
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