Introduction to JHipster Generator

JHipster is a development platform that allows you to generate, develop, and deploy Spring Boot + Angular / React / Vue web applications and Spring microservices. It is a highly popular open-source generator that combines the best of Java, Spring Boot, JPA/Hibernate, JavaScript, Angular, React, and much more, providing a robust full-stack development experience.

Creating an Application

To create a new application, use the following JHipster command:

  jhipster

Generating Entities

To generate entities, use the following command:

  jhipster entity MyEntity

This will prompt you to input various properties and relationships for the entity.

REST Service Example

JHipster offers a way to create RESTful services easily. Below is an example of creating a REST service:

  import org.springframework.web.bind.annotation.GetMapping;
  import org.springframework.web.bind.annotation.RequestParam;
  import org.springframework.web.bind.annotation.RestController;
  
  @RestController
  public class ExampleController {
    @GetMapping("/api/example")
    public String example(@RequestParam String param) {
      return "Your parameter is: " + param;
    }
  }

Using JPA Repositories

JPA repositories make interacting with your database straightforward. Here is an example:

  import org.springframework.data.jpa.repository.JpaRepository;
  import org.springframework.stereotype.Repository;

  @Repository
  public interface MyEntityRepository extends JpaRepository<MyEntity, Long> {
  }

Security Configuration

Configuring security is effortless with JHipster. Below is an example configuration:

  import org.springframework.context.annotation.Bean;
  import org.springframework.security.config.annotation.web.builders.HttpSecurity;
  import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
  import org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter;
  import org.springframework.security.crypto.bcrypt.BCryptPasswordEncoder;
  import org.springframework.security.crypto.password.PasswordEncoder;

  @EnableWebSecurity
  public class SecurityConfiguration extends WebSecurityConfigurerAdapter {
    @Override
    protected void configure(HttpSecurity http) throws Exception {
      http
        .authorizeRequests()
        .antMatchers("/api/**").authenticated()
        .anyRequest().permitAll()
        .and()
        .httpBasic();
    }

    @Bean
    public PasswordEncoder passwordEncoder() {
      return new BCryptPasswordEncoder();
    }
  }

Application Example

Here’s a complete example of a simple JHipster application. Assume we generated the application and an entity called Product with the following fields: name, description, and price.

  // Entity class for Product
  import javax.persistence.Entity;
  import javax.persistence.GeneratedValue;
  import javax.persistence.GenerationType;
  import javax.persistence.Id;

  @Entity
  public class Product {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    private String name;
    private String description;
    private double price;

    // Getters and setters
  }
  
  // Repository interface
  import org.springframework.data.jpa.repository.JpaRepository;
  import org.springframework.stereotype.Repository;
  
  @Repository
  public interface ProductRepository extends JpaRepository<Product, Long> {
  }
  
  // REST controller
  import org.springframework.web.bind.annotation.*;

  import java.util.List;

  @RestController
  @RequestMapping("/api/products")
  public class ProductController {
    private final ProductRepository productRepository;

    public ProductController(ProductRepository productRepository) {
      this.productRepository = productRepository;
    }

    @GetMapping
    public List<Product> getAllProducts() {
      return productRepository.findAll();
    }

    @PostMapping
    public Product createProduct(@RequestBody Product product) {
      return productRepository.save(product);
    }

    @GetMapping("/{id}")
    public Product getProductById(@PathVariable Long id) {
      return productRepository.findById(id).orElseThrow(() -> new RuntimeException("Product not found"));
    }
    
    @DeleteMapping("/{id}")
    public void deleteProduct(@PathVariable Long id) {
      productRepository.deleteById(id);
    }
  }

Conclusion

JHipster is indeed a powerful tool that can drastically speed up the development of your web applications. It provides a comprehensive set of tools and settings out of the box, which allows you to focus on business logic rather than boilerplate code. Happy coding!

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