Coding (General) Cheat Sheet (DRAFT) by bigocb

public int getNews() {

     @Value( "${api.url}" )
      private String uri;

     @Value( "${api.key}" )
      private String key;

    ObjectMapper mapper = new ObjectMapper();
    RestTemplate restTemplate = new RestTemplate();

    List<Articles> result = restTemplate.getForObject(uri + key, 
   InboundNewsResponse.class).getArticles();

    return 1
}

@Bean
public int getRest(RestTemplateBuilder restTemplateBuilder) {
        String baseUrl = <URL>
        RestTemplate restTemplate = restTemplateBuilder
                .setConnectTimeout(ncoaConnectTimeout)
                .setReadTimeout(ncoaReadTimeout)
                .build();

        return new NCOAClient(baseUrl, restTemplate);
    }

Random Number
public static double getRandomNumber(){
    double x = Math.random();
    return x;
}

Basic Get
@GetMapping(path = "/enp"
protected boolean get() {
      return true;
}

Info From Request Body
(@RequestBody String blah)

Info From Request Header
(@RequestHeader ("dp-token") String dpToken)

Receive File
@RequestMapping(value = "/upload", method = RequestMethod.POST, 
 consumes = MediaType.MULTIPART_FORM_DATA_VALUE)
   
public String fileUpload(@RequestParam("file") MultipartFile file) throws IOException {
      File convertFile = new File("/var/tmp/"+file.getOriginalFilename());
      convertFile.createNewFile();
      FileOutputStream fout = new FileOutputStream(convertFile);
      fout.write(file.getBytes());
      fout.close();
      return "File is upload successfully";
   }

toString
@Override
public String toString() {
  return "MailFwdRequest{" +
     "cfpsid='" + cfpsId + 
     ", btid=" + btId +
     '}';
}

import java.io.*; 
public class ReadingFromFile 
{ 
  public static void main(String[] args) throws Exception 
  { 
    // pass the path to the file as a parameter 
    FileReader fr = 
      new FileReader("C:\\Users\\pankaj\\Desktop\\test.txt"); 
  
    int i; 
    while ((i=fr.read()) != -1) 
      System.out.print((char) i); 
  } 
}

 
    @PostConstruct
    private void init() {
        log.info("InitDemoApplication initialization logic ...");
        // ...
    }

Trees
Trees Article

Maps
HashMap<String, Integer> map  = new HashMap<>(); 
map.put("vishal", 10); 
map.get("vishal"); 

Lists
List a = new ArrayList();
List b = new LinkedList();
List c = new Vector(); 
List d = new Stack(); 
List<Integer> l1 = new ArrayList<Integer>(); 
l1.add(0, 1);  // adds 1 at 0 index 
l1.add(1, 2);  // adds 2 at 1 index

private final DSLContext jooq;
    
@Transactional
public boolean selectExists(Long <var) {
   return jooq.fetchExists(
        select()
         .from(COA_INFORMED_DELIVERY)
         .where(<table>.<column>.eq(<var>))
      );
}

@Transactional(readOnly = true)
public List<MailFwdExtension> select(String cfpsId) {
    List<MailFwdExtensionsRecord> records = jooq
         .selectFrom(MAIL_FWD_EXTENSIONS)
         .where(MAIL_FWD_EXTENSIONS.CFPSID.eq(cfpsId))
         .fetchInto(MailFwdExtensionsRecord.class);
}

spring.datasource.url=jdbc:h2:mem:testdb
spring.datasource.driverClassName=org.h2.Driver
spring.datasource.username=sa
spring.datasource.password=
spring.h2.console.enabled=false

spring.h2.console.enabled=true
http://localhost:8080/h2-console

@Entity
public class Person {

    @Id
    @GeneratedValue
    private int id;
    private String name;
    private int age;
    private String emailId;

    //getters and setters
}

public interface PersonRepository extends CrudRepository<Person, Integer> {}

@Service
public class PersonService {

    @Autowired
    PersonRepository personRepository;

    public List<Person> getAllPersons() {
        List<Person> persons = new ArrayList<Person>();
        personRepository.findAll().forEach(person -> persons.add(person));
        return persons;
    }

    public Person getPersonById(int id) {
        return personRepository.findById(id).get();
    }

    public void saveOrUpdate(Person person) {
        personRepository.save(person);
    }

    public void delete(int id) {
        personRepository.deleteById(id);
    }
}