summary
먼저 아파치 톰캣이 이클립스에 연동되어있다고 가정한다.
서블릿으로 웹요청을 받아들여 디비랑 통신하기 위한 코드에 대한 템플릿이다.
DB와의 통신은 서블릿 코드에서 DBConnect.java를 통해 디비에 접속하고 Dao를 통해 질의문을 작성한다.
template_server.zip프로젝트 생성
이클립스 > File > New > Dynamic Web Project
서블릿 파일 생성
File > New > Servlet > 아래 코드
package templete_server.servlet;
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.ResultSet;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* Servlet implementation class GetData
*/
@WebServlet(name = "GetData", urlPatterns = { "/GetData" })
public class GetData extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public GetData() {
super();
// TODO Auto-generated constructor stub
}
protected void processRequest(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
response.setContentType("text/html;charset=UTF-8");
PrintWriter out = response.getWriter();
/////////////////////////////////////////////////////////////////
// HTML SOURCE CODE
out.println("<html>");
out.println("<head>");
out.println("<title>Servlet GetData</title>");
out.println("</head>");
out.println("<body>");
out.println("<h1>Servlet GetData at " + request.getContextPath()
+ "</h1>");
out.println("<p>");
out.println("get data : " + request.getParameter("id"));
out.println("</body>");
out.println("</html>");
out.println("");
// HTML SOURCE CODE
/////////////////////////////////////////////////////////////////
String id = request.getParameter("id");
System.out.println(id);
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse
* response)
*/
protected void doGet(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
processRequest(request, response);
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse
* response)
*/
protected void doPost(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
processRequest(request, response);
}
}DB Connect ( Mysql)
jdbc나 mysql 드라이버는 'WebContent > WEN-INF > lib' 안에 넣어주어야 한다.
첫 번째 코드는 DB를 연결하기 위함이고, 두 번째 코드는 질의문을 서버에 작성할 수 있다.
DBConnector.java
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
public class DBConnector {
private String driver = "com.mysql.jdbc.Driver";
private String url = "jdbc:mysql://localhost:3306/dbschema?useUnicode=true&characterEncoding=UTF-8";
private String user = "userid"; //DB user ID
private String pwd = "password"; //DB user Password
private Connection conn = null;
public Connection getConnection(){
try{
Class.forName(driver);
}catch(ClassNotFoundException e){
System.out.println("BusInfoSystem : 드라이버 로딩 실패(getConnection)");
System.out.println(e.getMessage());
}
try{
conn = DriverManager.getConnection(url,user,pwd);
}catch(SQLException e){
System.out.println("BusInfoSystem : DB 연결 실패(getConnection)");
System.out.println(e.getMessage());
}
return conn;
}
}
tempateDao.java
package templete_server.dao;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.Statement;
public class templateDao {
private DBConnector dbc;
public templateDao() {
dbc = new DBConnector();
}
public int getData(int arg1) {
int result = 0;
Connection conn = null;
PreparedStatement ps = null;
ResultSet rs = null;
String sql = new String("select * from dbtable where ID = ?;");
conn = dbc.getConnection();
try {
ps = conn.prepareStatement(sql);
ps.setInt(1, arg1);
rs = ps.executeQuery();
rs.first();
while (true) {
result = rs.getInt("id");
if (rs.isLast())
break;
rs.next();
}
} catch (Exception e) {
e.printStackTrace();
} finally {
closeDB(rs, ps, conn);
}
return result;
}
/**
* DataBase 자원 반환
*
* @param rs
* @param ps
* @param conn
*/
private void closeDB(ResultSet rs, Statement ps, Connection conn) {
if (rs != null) {
try {
rs.close();
} catch (Exception e) {
}
}
if (ps != null) {
try {
ps.close();
} catch (Exception e) {
}
}
if (conn != null) {
try {
conn.close();
} catch (Exception e) {
}
}
}
}
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