ScheduleDelete1.java

ScheduleDelete1.java

import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.sql.*;

public class ScheduleDelete1 extends HttpServlet{

    protected Connection conn = null;

    public void init() throws ServletException{
        String url = "jdbc:mysql://localhost/servletschedule";
        String user = "scheduleuser";
        String password = "schedulepass";

        try {
            Class.forName("com.mysql.jdbc.Driver").newInstance();
            conn = DriverManager.getConnection(url, user, password);
        }catch (ClassNotFoundException e){
            log("ClassNotFoundException:" + e.getMessage());
        }catch (SQLException e){
            log("SQLException:" + e.getMessage());
        }catch (Exception e){
            log("Exception:" + e.getMessage());
        }
    }

    public void destory(){
        try{
            if (conn != null){
                conn.close();
            }
        }catch (SQLException e){
            log("SQLException:" + e.getMessage());
        }
    }

    public void doGet(HttpServletRequest req, HttpServletResponse res)
        throws ServletException, IOException{

        req.setCharacterEncoding("Shift-JIS");
        res.setContentType("text/html;charset=Shift_Jis");
        PrintWriter out = res.getWriter();

        int id;
        int year;
        int month;

        String param = req.getParameter("ID");
        if (param == null || param.length() == 0){
            id = -999;
        }else{
            try{
                id = Integer.parseInt(param);
            }catch (NumberFormatException e){
                id = -999;
            }
        }

        param = req.getParameter("YEAR");
        if (param == null || param.length() == 0){
            year = -999;
        }else{
            try{
                year = Integer.parseInt(param);
            }catch (NumberFormatException e){
                year = -999;
            }
        }

        param = req.getParameter("MONTH");
        if (param == null || param.length() == 0){
            month = -999;
        }else{
            try{
                month = Integer.parseInt(param);
            }catch (NumberFormatException e){
                month = -999;
            }
        }

        /* IDが不正な値で来た場合はパラメータ無しで「MonthView」へリダイレクトする */
        if (id == -999){
            res.sendRedirect("/schedule/MonthView");
        }

        try {
            String sql = "delete from schedule where id = ?";
            PreparedStatement pstmt = conn.prepareStatement(sql);
            pstmt.setInt(1, id);

            int num = pstmt.executeUpdate();

            pstmt.close();

        }catch (SQLException e){
            out.println("SQLException:" + e.getMessage());
        }

        StringBuffer sb = new StringBuffer();
        sb.append("/schedule/MonthView");
        sb.append("?YEAR=");
        sb.append(year);
        sb.append("?MONTH=");
        sb.append(month);
        res.sendRedirect(new String(sb));

    }
}