noteservlet.java

留言管理系统,用JAVA JSP + MVC + DAO完成

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package com.shx.note.servlet;

import com.shx.note.factory.DAOFactory;
import com.shx.note.vo.Note;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 *
 * @author Administrator
 */
public class NoteServlet extends HttpServlet {

    // <editor-fold defaultstate="collapsed" desc="HttpServlet 方法。单击左侧的 + 号以编辑代码。">
    /** 
     * Handles the HTTP <code>GET</code> method.
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        this.doPost(request, response);
    }

    /** 
     * Handles the HTTP <code>POST</code> method.
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        // 进行乱码处理
        request.setCharacterEncoding("UTF-8");
        String path = null;
        // 声明一个集合类，用于保存错误信息
        List errors = new ArrayList();
        // 接收要操作的参数值
        String status = request.getParameter("status");
        if (status != null) {
            // 参数有内容，之后选择合适的方法
            // 查询全部操作
            if ("quaryAll".equals(status)) {
                try {
                    request.setAttribute("all", DAOFactory.getNoteDAOInstance().quaryAll());

                } catch (Exception ex) {
                    Logger.getLogger(NoteServlet.class.getName()).log(Level.SEVERE, null, ex);
                }
                path = "list_notes.jsp";
            }
            // 插入操作
            if ("insert".equals(status)) {
                // 1、接收插入的信息
                String title = request.getParameter("title");
                String author = request.getParameter("author");
                String content = request.getParameter("content");
                // 2、实例化Note对象
                Note note = new Note();
                note.setTitle(title);
                note.setAuthor(author);
                note.setContent(content);
                note.setErrors(errors);
                // 3、调用DAO完成数据库的插入操作
                boolean flag = false;
                //验证标题、作者、内容是否为空
                if (note.invalidate()) {
                    try {
                        DAOFactory.getNoteDAOInstance().insert(note);
                        flag = true;
                        request.setAttribute("flag", new Boolean(flag));
                        path = "insert_do.jsp";
                    } catch (Exception ex) {
                        Logger.getLogger(NoteServlet.class.getName()).log(Level.SEVERE, null, ex);
                    }
                } else {
                    path = "insert.jsp";
                    request.setAttribute("errors", errors);
                    request.setAttribute("note", note);
                }
            }
            // 按ID查询操作，为查看操作做准备
            if ("look".equals(status)) {
                int n_id = Integer.parseInt(request.getParameter("n_id"));
                try {
                    request.setAttribute("note", DAOFactory.getNoteDAOInstance().quaryById(n_id));
                } catch (Exception ex) {
                    Logger.getLogger(NoteServlet.class.getName()).log(Level.SEVERE, null, ex);
                }
                path = "look.jsp";
            }
            // 按ID查询操作，修改之前需要将数据先查询出来
            if ("quaryById".equals(status)) {
                int n_id = Integer.parseInt(request.getParameter("n_id"));
                try {
                    request.setAttribute("note", DAOFactory.getNoteDAOInstance().quaryById(n_id));
                } catch (Exception ex) {
                    Logger.getLogger(NoteServlet.class.getName()).log(Level.SEVERE, null, ex);
                }
                path = "update.jsp";
            }
            // 更新操作
            if ("update".equals(status)) {
                int n_id = Integer.parseInt(request.getParameter("n_id"));
                // 1、接收更新的信息
                String title = request.getParameter("title");
                String author = request.getParameter("author");
                String content = request.getParameter("content");
                // 2、实例化VO对象
                Note note = new Note();
                note.setN_id(n_id);
                note.setTitle(title);
                note.setAuthor(author);
                note.setContent(content);
                //note.setErrors(errors);
                // 3、调用DAO完成数据库的插入操作
                boolean flag = false;
                //if (note.invalidate()) {
                try {
                    DAOFactory.getNoteDAOInstance().update(note);
                    flag = true;
                    request.setAttribute("flag", new Boolean(flag));
                    path = "update_do.jsp";
                } catch (Exception ex) {
                    Logger.getLogger(NoteServlet.class.getName()).log(Level.SEVERE, null, ex);
                }
            /*} else {
            request.setAttribute("note", note);
            path = "update";
            }*/
            }
            // 模糊查询操作
            if ("quaryByLike".equals(status)) {
                String keyword = request.getParameter("keyword");
                try {
                    request.setAttribute("all", DAOFactory.getNoteDAOInstance().quaryByLike(keyword));
                } catch (Exception e) {
                }
                path = "list_notes.jsp";
            }
            // 删除操作
            if ("delete".equals(status)) {
                // 接收参数
                int n_id = Integer.parseInt(request.getParameter("n_id"));
                boolean flag = false;
                try {
                    DAOFactory.getNoteDAOInstance().delete(n_id);
                    flag = true;
                } catch (Exception ex) {
                    Logger.getLogger(NoteServlet.class.getName()).log(Level.SEVERE, null, ex);
                }
                request.setAttribute("flag", new Boolean(flag));
                path = "delete_do.jsp";
            }
        } else {
            // 则表示无参数，非法的客户请求
            path = "errors.jsp";
        }
        request.getRequestDispatcher(path).forward(request, response);
    }
}