简单的查询
##简单的查询
项目结构图
##index页面
`<%@ page language=“java” contentType=“text/html; charset=UTF-8”
pageEncoding=“UTF-8”%>
XXXX点餐系统
##home页面
<%@ page language=“java” contentType=“text/html; charset=UTF-8” pageEncoding=“UTF-8”%>
<%@ taglib uri=“http://java.sun.com/jsp/jstl/core” prefix=“c” %>
<%@ taglib uri=“http://java.sun.com/jsp/jstl/functions” prefix=“fn” %>
添加菜品
序号
菜名
菜品说明
${status.count}
${m.foodname}
${m.explain}
##dao 包中的MenumerationDao.java
package dao;
import java.sql.SQLException;
import java.util.List;
import javax.sql.DataSource;
import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.BeanListHandler;
import domain.Menu;
import utils.DataSourceUtils;
public class MenuDao {
/**
* 查询所有数据
* @throws SQLException
*/
public List
String sql = “SELECT * FROM MENU”;
QueryRunner runner = new QueryRunner(DataSourceUtils.getDataSource());
List menuList = runner.query(sql, new BeanListHandler (Menu.class));
return menuList;
}
/**
* 通过菜品名来查询数据
*/
public List}
##domain包中的Menu.java
package domain;
/**
- 菜单表的实例化
- @author
*/
public class Menu {
private int id;
private String foodname;
private String explain;
@Override
public String toString() {
return "Menu [id=" + id + ", foodname=" + foodname + ", explain=" + explain + "]";
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getFoodname() {
return foodname;
}
public void setFoodname(String foodname) {
this.foodname = foodname;
}
public String getExplain() {
return explain;
}
public void setExplain(String explain) {
this.explain = explain;
}
}
##servlet 包中的servlet文件
##FindByFoodNameServlet.java
package servlet;
import java.io.IOException;
import java.sql.SQLException;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import dao.MenuDao;
import domain.Menu;
/**
-
Servlet implementation class FindByFoodNameServlet
*/
@WebServlet("/FindByFoodNameServlet")
public class FindByFoodNameServlet extends HttpServlet {
private static final long serialVersionUID = 1L;/**
- @see HttpServlet#HttpServlet()
*/
public FindByFoodNameServlet() {
super();
// TODO Auto-generated constructor stub
}
/**
-
@see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
menuList = null;
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//设置编码类型
request.setCharacterEncoding(“UTF-8”);
String foodname = request.getParameter(“foodname”);
MenuDao menuDao = new MenuDao();
List
try {
menuList = menuDao.findByFoodName(foodname);
request.setAttribute(“menuList”, menuList);
request.getRequestDispatcher(“home.jsp”).forward(request, response);
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}// TODO Auto-generated method stub
response.getWriter().append("Served at: ").append(request.getContextPath());
}
/**
- @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
doGet(request, response);
}
- @see HttpServlet#HttpServlet()
}
##LoginServlet.java
package servlet;
import java.io.IOException;
import java.sql.SQLException;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import dao.MenuDao;
import domain.Menu;
/**
-
Servlet implementation class LoginServlet
*/
@WebServlet("/LoginServlet")
public class LoginServlet extends HttpServlet {
private static final long serialVersionUID = 1L;/**
- @see HttpServlet#HttpServlet()
*/
public LoginServlet() {
super();
// TODO Auto-generated constructor stub
}
/**
-
@see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {MenuDao menuDao = new MenuDao();
List// TODO Auto-generated method stub
response.getWriter().append("Served at: ").append(request.getContextPath());
}
/**
- @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
doGet(request, response);
}
- @see HttpServlet#HttpServlet()
}
##utils包中的文件
##DataSourceUtils.java
package utils;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import javax.sql.DataSource;
import com.mchange.v2.c3p0.ComboPooledDataSource;
public class DataSourceUtils {
private static DataSource dataSource = new ComboPooledDataSource();
private static ThreadLocal tl = new ThreadLocal();
// 直接可以获取一个连接池
public static DataSource getDataSource() {
return dataSource;
}
// 获取连接对象
public static Connection getConnection() throws SQLException {
Connection con = tl.get();
if (con == null) {
con = dataSource.getConnection();
tl.set(con);
}
return con;
}
// 开启事务
public static void startTransaction() throws SQLException {
Connection con = getConnection();
if (con != null) {
con.setAutoCommit(false);
}
}
// 事务回滚
public static void rollback() throws SQLException {
Connection con = getConnection();
if (con != null) {
con.rollback();
}
}
// 提交并且 关闭资源及从ThreadLocall中释放
public static void commitAndRelease() throws SQLException {
Connection con = getConnection();
if (con != null) {
con.commit(); // 事务提交
con.close();// 关闭资源
tl.remove();// 从线程绑定中移除
}
}
// 关闭资源方法
public static void closeConnection() throws SQLException {
Connection con = getConnection();
if (con != null) {
con.close();
}
}
public static void closeStatement(Statement st) throws SQLException {
if (st != null) {
st.close();
}
}
public static void closeResultSet(ResultSet rs) throws SQLException {
if (rs != null) {
rs.close();
}
}
}
##JDBCUtils.java
package utils;
/*
- 实现JDBC的工具类
- 定义方法，直接返回数据库的连接对象
- 关闭方法
*/
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import javax.management.RuntimeErrorException;
public class JDBCUtils {
private JDBCUtils(){}
private static Connection con ;
static{
try{
Class.forName("com.mysql.jdbc.Driver");
String url = "jdbc:mysql://localhost:3306/demo";
String username="root";
String password="root";
con = DriverManager.getConnection(url, username, password);
}catch(Exception ex){
throw new RuntimeException(ex+"数据库连接失败");
}
}
/*
* 定义静态方法,返回数据库的连接对象
*/
public static Connection getConnection(){
return con;
}
public static void close(Connection con,Statement stat,ResultSet rs){
if(rs!=null){
try{
rs.close();
}catch(SQLException ex){}
}
if(stat!=null){
try{
stat.close();
}catch(SQLException ex){}
}
if(con!=null){
try{
con.close();
}catch(SQLException ex){}
}
}
public static void close(Connection con,Statement stat){
if(stat!=null){
try{
stat.close();
}catch(SQLException ex){}
}
if(con!=null){
try{
con.close();
}catch(SQLException ex){}
}
}
}
##c3p0-comfig.xml
root aisino123 com.mysql.jdbc.Driver jdbc:mysql:///demo##lib里的包