controller/MemberController.java

package com.example.firstproject.controller;

import com.example.firstproject.entity.Member;
import com.example.firstproject.dto.MemberForm;
import com.example.firstproject.repository.MemberRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;

@Controller
public class MemberController {
    @Autowired
    MemberRepository memberRepository;

    @GetMapping("/signup")
    public String signUpPage() {
        return "members/new";
    }

    @PostMapping("/join")
    public String join(MemberForm memberForm) {
        System.out.println(memberForm.toString());
        Member member = memberForm.toEntity();
        System.out.println(member.toString());
        Member saved = memberRepository.save(member);
        System.out.println(saved.toString());
        return "";
    }
}

dto/MemberForm.java

package com.example.firstproject.dto;

import com.example.firstproject.entity.Member;

public class MemberForm {
    private String email;
    private String password;

    public MemberForm(String email, String password) {
        this.email = email;
        this.password = password;
    }

    @Override
    public String toString() {
        return "User{" +
                "email='" + email + '\'' +
                ", password='" + password + '\'' +
                '}';
    }

    public Member toEntity() {
        return new Member(null, email, password);
    }
}

entity/Member.java

package com.example.firstproject.entity;

import jakarta.persistence.Column;
import jakarta.persistence.Entity;
import jakarta.persistence.GeneratedValue;
import jakarta.persistence.Id;

@Entity
public class Member {
    @Id
    @GeneratedValue
    Long id;

    @Column
    String email;

    @Column
    String password;

    public Member(Long id, String email, String password) {
        this.id = id;
        this.email = email;
        this.password = password;
    }

    @Override
    public String toString() {
        return "Member{" +
                "id=" + id +
                ", email='" + email + '\'' +
                ", password='" + password + '\'' +
                '}';
    }
}

repository/MemberRepository.java

package com.example.firstproject.repository;

import com.example.firstproject.entity.Member;
import org.springframework.data.repository.CrudRepository;

public interface MemberRepository extends CrudRepository<Member, Long> {
}