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Building Scalable Applications with Thymeleaf and Spring Boot

Introduction to Displaying Data

Learn how to generate random users in the database.

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Generate random users

The first thing we need is a few users in our database for testing. We could create a database script to do that, but it’s easier to write a simple Java class that can create things in a loop.

Let’s start by creating a CommandLineRunner implementation. Spring will run any such beans at the startup of the application. By only enabling the bean when the init-db profile is active, we can toggle if the database should be populated at startup or not.

This is the code for the DatabaseInitializer:

Java
package com.tamingthymeleaf.application;
import com.github.javafaker.Faker;
import com.github.javafaker.Name;
import com.tamingthymeleaf.application.user.*;
import org.apache.commons.lang3.StringUtils;
import org.springframework.boot.CommandLineRunner;
import org.springframework.context.annotation.Profile;
import org.springframework.stereotype.Component;
import java.time.LocalDate;
import java.time.ZoneId;
@Component
@Profile("init-db") //<.>
public class DatabaseInitializer implements CommandLineRunner { //<.>
    private final Faker faker = new Faker(); //<.>
    private final UserService userService;
    public DatabaseInitializer(UserService userService) { //<.>
        this.userService = userService;
    }
    @Override
    public void run(String... args) {
        for (int i = 0; i < 20; i++) { //<.>
            CreateUserParameters parameters = newRandomUserParameters();
            userService.createUser(parameters);
        }
    }
    private CreateUserParameters newRandomUserParameters() {
        Name name = faker.name();
        UserName userName = new UserName(name.firstName(), name.lastName());
        Gender gender = faker.bool().bool() ? Gender.MALE : Gender.FEMALE;
        LocalDate birthday = LocalDate.ofInstant(faker.date().birthday(10, 40).toInstant(), ZoneId.systemDefault());
        Email email = new Email(faker.internet().emailAddress(generateEmailLocalPart(userName)));
        PhoneNumber phoneNumber = new PhoneNumber(faker.phoneNumber().phoneNumber());
        return new CreateUserParameters(userName, gender, birthday, email, phoneNumber);
    }
    private String generateEmailLocalPart(UserName userName) {
        return String.format("%s.%s",
                             StringUtils.remove(userName.getFirstName().toLowerCase(), "'"),
                             StringUtils.remove(userName.getLastName().toLowerCase(), "'"));
    }
}
  • Only have this @Component active when the init-db profile is active.
  • Implement CommandLineRunner interface so that
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