JAVA 기반 웹개발/SERVLET & JSP
Servlet 예제 ( 회원 저장 / 조회 )
by 거북이의 기술블로그
2024. 8. 27.
1. 구성
2. 구현
3. 정리
구성
구현
- java 클래스내부에 print 객체와 함께 동적 html을 생성한다
- html 코드로 인해, 코드가 길어지고 가독성이 떨어진다 (유지보수의 어려움)
public class Member{
private Long id;
private String username;
private int age;
public Member(){
}
public Member(String username, int age)
{
this.username = username;
this.age = age;
}
public int getId()
{
return this.id;
}
public void setId(int id)
{
this.id = id;
}
public String getUsername()
{
return this.username;
}
public void setUsername(String username)
{
this.username = username;
}
public int getAge()
{
return this.age;
}
public void setAge(int age)
{
this.age = age;
}
}
class MemberRepository{
private Map<Long, Member> store = new HashMap<>();
private static long sequence = 0L;
private final static MemberRepository instance = new MemberRepository();
private static MemberRepository getInstance()
{
return instance;
}
private MemberRepository(){}
public Member save(Member member)
{
member.setId(++sequence);
store.put(member.getId(), member);
return member;
}
public Member findById(Long id)
{
return store.get(id);
}
public List<Member> findAll()
{
return ArrayList<>(store.values());
}
}
@WebServlet(urlPatterns="/servlet/members/new-form")
public class MemberFormServlet extends HttpServlet{
@Override
protected void service (HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
{
response.setContentType("text/html");
response.setCharsetEncoding("utf-8");
PrintWriter w = response.getWriter();
w.write( "<!DOCTYPE html>\n" + "<html>\n" + "<head>\n" + "<meta charset="UTF-8">\n" + "</head>\n" + "<body>\n"
+ "<form action = \" /servlet/members/save\" method=\"post\">\n"
+ "username : <input type=\"text\" name=\"username\" /> \n"
+ " age : <input type=\"text\" name=\"age\" />\n"
+ <button type =\"submit\"> 전송 </button>\n"
"</form>"
+"</body>"
+"</html>" );
}
}
@WebServlet(urlPatterns="/servlet/members/save")
public class MemberSaveServlet extends HttpServlet{
private MemberRepository memberRepository = MemberRepository.getInstance();
@Override
protected void service ( HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
{
String username = request.getParameter("username");
int age = Integer.parseInt(request.getParameter("age"));
Member member = new Member(username, age);
memberRepository.save(member);
response.setContentType("text/html");
response.setCharacterEncoding("utf-8");
PrintWriter w = response.getWriter();
w.write("<html>\n" + "<head>\n" + "<meta charset = \"UTF-8"\>\n" + "</head>"
+ "<body>\n" + "성공\n"
+"<ul>\n"
+ " <li>id="+member.getId()+"</li?\n"
+ " <li>id="+member.userName()+"</li?\n"
+ " <li>id="+member.getAge()+"</li?\n"
+ "</ul>\n"
+ "</body>"
" "</html>"
}
}
정리
- 장점
- 자바 코드로 되어있어, 객체 값을 가져오기가 수월하다
- 서블릿을 통해 웹서비스의 동적 html을 만들수 있다
- 단점
- html을 직접 자바코드로 만들면서 반복적인 부분들이 존재한다
- 코드의 길이가 길어지면서 가독성이 떨어진다
- 분리되어있지 않아 유지보수의 어려움이 존재한다
단점들을 보완하고자, "템플릿 엔진"이 나오게 되었다