BackEnd/Java
Java :: JDBC DAO 소스
초록 (green)
2016. 4. 26. 23:39
Servlet + jstl + JDBC 를 이용한 게시판 소스 중 JDBC DAO 파일 소스 전문 JDBC를 공부하다가,
Mybatis로 발전해서 게시판 프로젝트 공부를 했었는데
다시 JDBC를 이용하여 혼자 힘으로 해보려니 조금 어려운 면이 있기도 했다.
확실히 Mybatis가 편하다.
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package com.dao;
import java.sql.*;
import java.util.*;
import com.vo.Person;
public class PersonDAO implements PersonDAOImpl {
Connection conn = null;
PreparedStatement pstmt = null;
ResultSet rs = null;
String url = "jdbc:mysql://localhost:3306/basicjsp?useUnicode=true&characterEncoding=utf8&zeroDateTimeBehavior=convertToNull";
String id = "jspid";
String pass = "jsppass";
String sql = "";
public void connectDB() {
try {
Class.forName("com.mysql.jdbc.Driver");
conn = DriverManager.getConnection(url, id, pass);
}
catch (Exception e) {
e.printStackTrace();
}
}
@Override
public List<HashMap<String, Object>> selectAll() {
List<HashMap<String, Object>> list = new ArrayList<HashMap<String, Object>>();
try {
sql = "SELECT id, name, sex, age, DATE_FORMAT(date, '%Y-%m-%d') AS date, rcount FROM persons";
pstmt = conn.prepareStatement(sql);
rs = pstmt.executeQuery();
while (rs.next()) {
connectDB();
HashMap<String, Object> params = new HashMap<String, Object>();
params.put("id", rs.getInt("id"));
params.put("name", rs.getString("name"));
params.put("sex", rs.getString("sex"));
params.put("age", rs.getInt("age"));
params.put("date", rs.getShort("date"));
params.put("rcount", rs.getInt("rcount"));
params.put("column", "id");
params.put("sort", "ASC");
list.add(params);
}
conn.close();
pstmt.close();
rs.close();
}
catch (Exception e) {
e.printStackTrace();
}
return list;
}
@Override
public List<HashMap<String, Object>> selectAllLimit(int offset, int recordsPerPage,
String sortItem, String sortMethod) {
List<HashMap<String, Object>> list = new ArrayList<HashMap<String, Object>>();
try {
connectDB();
sql = "SELECT id, name, sex, age, DATE_FORMAT(date, '%Y-%m-%d') AS date, rcount FROM persons ";
if (sortItem != null && sortItem.equals("id")) {
sql += "ORDER BY id ";
}
else if (sortItem != null && sortItem.equals("name")) {
sql += "ORDER BY name ";
}
else
sql += "ORDER BY age ";
if (sortMethod != null && sortMethod.equals("ASC")) {
sql += "ASC ";
}
else {
sql += "DESC ";
}
sql += "LIMIT " + offset + ", " + recordsPerPage;
pstmt = conn.prepareStatement(sql);
rs = pstmt.executeQuery();
while (rs.next()) {
HashMap<String, Object> params = new HashMap<String, Object>();
params.put("id", rs.getInt("id"));
params.put("name", rs.getString("name"));
params.put("sex", rs.getString("sex"));
params.put("age", rs.getInt("age"));
params.put("date", rs.getString("date"));
params.put("rcount", rs.getInt("rcount"));
params.put("offset", offset);
params.put("recordsPerPage", recordsPerPage);
params.put("sortItem", sortItem);
params.put("sortMethod", sortMethod);
list.add(params);
}
conn.close();
pstmt.close();
rs.close();
}
catch (Exception e) {
e.printStackTrace();
}
return list;
}
@Override
public Person selectById(int id) {
Person person = new Person();
try {
connectDB();
sql = "SELECT * FROM persons WHERE id = ?";
pstmt = conn.prepareStatement(sql);
pstmt.setLong(1, id);
rs = pstmt.executeQuery();
while (rs.next()) {
person.setId(rs.getInt(1));
person.setName(rs.getString(2));
person.setSex(rs.getString(3));
person.setAge(rs.getInt(4));
person.setDate(rs.getString(5));
person.setrCount(rs.getInt(6));
}
conn.close();
pstmt.close();
rs.close();
} catch (Exception e) { }
return person;
}
@Override
public int selectCount() {
int n = 0;
try {
connectDB();
String sql = "SELECT COUNT(*) FROM persons";
pstmt = conn.prepareStatement(sql);
rs = pstmt.executeQuery();
rs.next();
n = rs.getInt(1);
pstmt.close();
rs.close();
} catch (Exception e) { }
return n;
}
@Override
public int insert(Person person) {
int id = -1;
sql = "INSERT INTO persons (name, sex, age, rcount) VALUES (?, ?, ?, 0)";
try {
connectDB();
pstmt = conn.prepareStatement(sql);
pstmt.setString(1, person.getName());
pstmt.setString(2, person.getSex());
pstmt.setInt(3, person.getAge());
pstmt.executeUpdate();
pstmt.close();
conn.close();
}
catch (SQLException e) {
e.printStackTrace();
}
return id;
}
@Override
public void update(Person person) {
sql = "UPDATE persons SET name = ? , sex = ?, age = ? WHERE id = ?";
try {
connectDB();
pstmt = conn.prepareStatement(sql);
pstmt.setString(1, person.getName());
pstmt.setString(2, person.getSex());
pstmt.setInt(3, person.getAge());
pstmt.setInt(4, person.getId());
pstmt.executeUpdate();
pstmt.close();
conn.close();
}
catch (Exception e) {
e.printStackTrace();
}
}
@Override
public void updateCount(int id) {
sql = "UPDATE persons SET rcount = rcount + 1 WHERE id = ?";
try {
connectDB();
pstmt = conn.prepareStatement(sql);
pstmt.setInt(1, id);
pstmt.executeUpdate();
pstmt.close();
conn.close();
}
catch (Exception e) {
e.printStackTrace();
}
}
@Override
public void delete(int id) {
sql = "DELETE FROM persons WHERE id = ?";
try {
connectDB();
pstmt = conn.prepareStatement(sql);
pstmt.setInt(1, id);
pstmt.executeUpdate();
pstmt.close();
conn.close();
}
catch (Exception e) {
e.printStackTrace();
}
}
} |
cs |
- selectAll : 리스트 전체 출력 메소드
- selectAllLimit : 정렬 방식에 따라 변경되는 리스트 출력 메소드
if문과 LIMIT 를 이용한 쿼리를 구현하는데에서 시행착오가 조금 있었다.
- selectById : 특정 게시글을 선택했을 때 해당 글 하나의 정보만을 출력하는 메소드
- selectCount : 전체 리스트 수를 출력하는 메소드
- insert : 게시글 삽입 메소드
- update : 게시글 수정 메소드
- updateCount : 게시글 조회수 증가 메소드
- delete : 게시글 삭제 메소드