Servlet - Connection with DB

Servlet을 사용할 때, DB는 어떻게 연결을 했을까?

다양한 방법으로 소개를 하고 추후 이를 토대로 발전사를 정리해보고자 한다.

 

앞으로 다뤄볼 내용의 구조는 다음과 같다. 

servletController - memberDAO - memberVO

servletController : 요청에 대한 처리를 할 Servlet

memberDAO : DB 처리할 Servlet

memberVO : DB와 관련된 객체를 담을 Servlet

 

// Controller

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
	// MemberDAO 객체 선언
    MemberDAO dao=new MemberDAO();
    // MemberDAO 객체의 메서드 중 listMembers()호출 후 반환값 담기
	List<MemberVO> list=dao.listMembers();
    // VO의 메서드를 통해 출력
    for (int i=0; i<list.size();i++){
			MemberVO memberVO=(MemberVO) list.get(i);
			String id=memberVO.getId();
			String pwd = memberVO.getPwd();
			String name=memberVO.getName();
			String email=memberVO.getEmail();
			Date joinDate = memberVO.getJoinDate();
	}
}


// VO

private String id;
private String pwd;
private String name;
private String email;
private Date joinDate;
public MemberVO() {
    System.out.println("MemberVO 생성자 호출");
}
public String getId() {
    return id;
}
public void setId(String id) {
    this.id = id;
}
public String getPwd() {
    return pwd;
}
public void setPwd(String pwd) {
    this.pwd = pwd;
}
public String getName() {
    return name;
}
public void setName(String name) {
    this.name = name;
}
public String getEmail() {
    return email;
}

public void setEmail(String email) {
    this.email = email;
}
public Date getJoinDate() {
    return joinDate;
}
public void setJoinDate(Date joinDate) {
    this.joinDate = joinDate;
}




// DAO

// DB 연결 정보
private static final String driver = "oracle.jdbc.driver.OracleDriver";
private static final String url = "jdbc:oracle:thin:@localhost:1521:XE";
private static final String user = "id";
private static final String pwd = "pwd";
private Connection con;
private Statement stmt;

public List<MemberVO> listMembers() {
    List<MemberVO> list = new ArrayList<MemberVO>();
    try {
        connDB();
        String query = "select * from jaemin.t_member ";
        System.out.println(query);
        ResultSet rs = stmt.executeQuery(query);
        while (rs.next()) {
            String id = rs.getString("id");
            String pwd = rs.getString("pwd");
            String name = rs.getString("name");
            String email = rs.getString("email");
            Date joinDate = rs.getDate("joinDate");
            MemberVO vo = new MemberVO();
            vo.setId(id);
            vo.setPwd(pwd);
            vo.setName(name);
            vo.setEmail(email);
            vo.setJoinDate(joinDate);
            list.add(vo);
        }
        rs.close();
        stmt.close();
        con.close();
    } catch (Exception e) {
        e.printStackTrace();
    }
    return list;
}

private void connDB() {
    try {
        Class.forName(driver);
        System.out.println("Oracle 드라이버 로딩 성공");
        con = DriverManager.getConnection(url, user, pwd);
        System.out.println("Connection 생성 성공");
        stmt = con.createStatement();
        System.out.println("Statement 생성 성공");
    } catch (Exception e) {
        e.printStackTrace();
    }
}