Blog of Java Programmer

Sort digits with ArrayList:

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;

public class Solution {
public static void main(String[] args) throws IOException {
// insert code here
BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));

ArrayList mainList = new ArrayList();
for (int i = 0; i < 20; i++) {
mainList.add(Integer.parseInt(reader.readLine()));
}

ArrayList multipleThree = new ArrayList();
ArrayList multipleTwo = new ArrayList();
ArrayList multipleThreeAndTwo = new ArrayList();

for (int i = 0; i < mainList.size(); i++) {
Integer figure = mainList.get(i);

if (figure % 3 == 0 || figure % 2 == 0) {
if (figure % 3 == 0) {
multipleThree.add(figure);
}
if (figure % 2 == 0) {
multipleTwo.add(figure);
}
}else {
multipleThreeAndTwo.add(figure);
}
}

Java coding

Оператор деления по модулю - оператор mod, обозначается символом %.
Этот оператор возвращает остаток от деления первого операнда на второй.
Оператор mod "%" в Java работает не только с целыми (такие как: byte/int/short/long),
но и с плавающей точкой (такие как: float/double) числами\типами.

https://examples.javacodegeeks.com/enterprise-java/jpa/java-persistence-xml-example/

JPA persistence.xml Example | Examples Java Code Geeks - 2021 In this tutorial, we will show how to implement the Java Persistence API and define the JPA Persistence Units with EclipseLink and MySQL in Java.

Pattern: Object Pool

public class PullObjects {
public static void main(String[] args) {
ObjectPool objectPool = new ObjectPool();
PooledObject pooledObject = objectPool.getPooledObject();
objectPool.releasePooledObject(pooledObject);
}
}

class PooledObject {

}
// басейн
class ObjectPool {
List free = new LinkedList();
List used = new LinkedList();

public PooledObject getPooledObject() {
if (free.isEmpty()) {
PooledObject pooledObject = new PooledObject();
free.add(pooledObject);
return pooledObject;
}else {
PooledObject pooledObject = free.get(0);
used.add(pooledObject);
free.remove(pooledObject);
return pooledObject;
}
}

public void releasePooledObject(PooledObject pooledObject) {
used.remove(pooledObject);
free.add(pooledObject);
}
}

Код для контроллера блога

package com.fara0n.blog.controllers;

import com.fara0n.blog.models.Post;
import com.fara0n.blog.repo.PostRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestParam;

import java.util.ArrayList;
import java.util.Optional;


public class BlogController {


private PostRepository postRepository;

("/blog")
public String blogMain(Model model) {
Iterable posts = postRepository.findAll();
model.addAttribute("posts", posts);
return "blog-main";
}

("/blog/add")
public String blogAdd(Model model) {
return "blog-add";
}

("/blog/add")
public String blogPostAdd( String title, String anons, String full_text, Model model) {
Post post = new Post(title, anons, full_text);
postRepository.save(post);
return "redirect:/blog";
}

("/blog/{id}")
public String blogDetails((value = "id") long id, Model model) {
if (!postRepository.existsById(id)) {
return "redirect:/blog";
}

Optional post = postRepository.findById(id);
ArrayList res = new ArrayList();
post.ifPresent(res::add);
model.addAttribute("post", res);
return "blog-details";
}

("/blog/{id}/edit")
public String blogEdit((value = "id") long id, Model model) {
if (!postRepository.existsById(id)) {
return "redirect:/blog";
}

Optional post = postRepository.findById(id);
ArrayList res = new ArrayList();
post.ifPresent(res::add);
model.addAttribute("post", res);
return "blog-edit";
}

("/blog/{id}/edit")
public String blogPostUpdate((value = "id") long id, String title, String anons, String full_text, Model model) {
Post post = postRepository.findById(id).orElseThrow();
post.setTitle(title);
post.setAnons(anons);
post.setFull_text(full_text);
postRepository.save(post);
return "redirect:/blog";
}

("/blog/{id}/remove")
public String blogPostDelete((value = "id") long id, Model model) {
Post post = postRepository.findById(id).orElseThrow();
postRepository.delete(post);
return "redirect:/blog";
}
}

Настройки подключения Spring к базе данных mySQL:
spring.jpa.hibernate.ddl-auto=update
spring.datasource.url=jdbc:mysql://${MYSQL_HOST:localhost}:3306/Имя_базы_данных
spring.datasource.username=root
spring.datasource.password=root
(файл - application.properties)

pom зависимости:
spring.jpa.hibernate.ddl-auto=update
spring.datasource.url=jdbc:mysql://${MYSQL_HOST:localhost}:3306/spring_web_blog
spring.datasource.username=root
spring.datasource.password=root

Эта страница будет временной площадкой для блога, основной сайт разрабатывается!
Let's continue to discuss about Spring and java Android development!

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