Mybatis) 총 학생 수 조회, 학생 정보 한 건 조회

안녕하세요, 코린이의 코딩 학습기 채니 입니다.

개인 포스팅용으로 내용에 오류 및 잘못된 정보가 있을 수 있습니다.

총 학생 수 조회

url-command.properties

/student/selectOne.do = com.ce.app.student.controller.SelectOneController

Controller

SelectOneController

public class SelectOneController extends AbstractController {
	static final Logger log = Logger.getLogger(SelectOneController.class);
	private StudentService studentService;
	
	public SelectOneController(StudentService studentService) {
		super();
		this.studentService = studentService;
	}

	@Override
	public String doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		int totalCount = studentService.getTotalCount();
		request.setAttribute("totalCount", totalCount);
		return "student/selectOne";
	}
}

Service

StudentService interface 생략

StudentServiceImpl

@Override
public int getTotalCount() {
    try(SqlSession sqlSession = getSqlSession()) {			
        return studentDao.getTotalCount(sqlSession);
    }
}

Dao

StudentDao interface 생략

StudentDaoImpl

@Override
public int getTotalCount(SqlSession sqlSession) {
    return sqlSession.selectOne("student.getTotalCount");
}

리턴 레코드가 1 또는 0이기 때문에 selectOne 메소드를 이용해줍니다.

student-mapping.xml

<select id="getTotalCount" resultType="_int">
    select count(*) from student where deleted_at is null
</select>

select의 경우 반드시 resultType / resultMap 속성을 반드시 작성해야 하기 때문에 내장별칭인 "_int"를 입력해주었습니다.

(parameterType은 생략 가능!)

selectOne.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Mybatis 실습</title>
<script src="${pageContext.request.contextPath}/js/jquery-3.6.0.js"></script>
<style>
div#student-container{text-align:center;}
table.tbl-student{margin:10px auto;border:1px solid; border-collapse:collapse;}
table.tbl-student th,table.tbl-student td{
	border:1px solid;
	padding:5px;
	line-height: 2em; /*input태그로 인해 cell이 높이가 길어져 border 두줄현상방지 */
}
table.tbl-student th{text-align:right;}
table.tbl-student td{text-align:left;}
table.tbl-student tr:last-of-type td:first-child{text-align:center;}
</style>
</head>
<body>
	<div id="student-container">
		<h2>학생정보 검색</h2>
		<p>등록된 학생 수는 <span id="totalCount">${totalCount}</span>명입니다.</p>
		<form name="studentSearchFrm">
			<table class="tbl-student">
				<tr>
					<th>학생번호</th>
					<td>
						<input type="number" name="no" value="" required/>
					</td>
				</tr>
				<tr>
					<td colspan="2">
						<input type="submit" value="검색" />
					</td>
				</tr>
			</table>
		</form>
	</div>
</body>
</html>

학생 정보 한 건 조회

url-command.properties

/student/student.do = com.ce.app.student.controller.StudentController

Controller

StudentController

public class StudentController extends AbstractController {
	static final Logger log = Logger.getLogger(StudentController.class);
	private StudentService studentService;
	
	public StudentController(StudentService studentService) {
		super();
		this.studentService = studentService;
	}
	
	@Override
	public String doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		int no = Integer.parseInt(request.getParameter("no"));
		log.debug("no = " + no);
		Student student = studentService.selectOneStudent(no);
		
		response.setContentType("application/json; charset=utf-8");
		new Gson().toJson(student, response.getWriter());
		
		return null;
	}
}