写一个简单的增删改查

1、首先要有一个JavaBean

package com.tnr.bean;

public class Car {
	private int c_id;
	private String c_name;
	private int c_price;
	public int getC_id() {
		return c_id;
	}
	public void setC_id(int c_id) {
		this.c_id = c_id;
	}
	public String getC_name() {
		return c_name;
	}
	public void setC_name(String c_name) {
		this.c_name = c_name;
	}
	public int getC_price() {
		return c_price;
	}
	public void setC_price(int c_price) {
		this.c_price = c_price;
	}
	
}

2、需要一个Servlet（主要是用来获取参数以及页面跳转的方法）

package com.tnr.servlet;

import java.io.IOException;
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 com.tnr.bean.Car;
import com.tnr.service.CarService;


@WebServlet({
	"/carList",
	"/carDoAdd",
	"/carToAdd",
	"/carToUpd",
	"/carDoUpd",
	"/carDoDel"	
})


public class CarServlet extends HttpServlet{
	
	@Override
	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		req.setCharacterEncoding("UTF-8");
		
		String path=req.getServletPath();
		
		CarService service=new CarService();
		
		if("/carList".equals(path)) {
			List<Car> list=service.getCarList();
			
			req.setAttribute("carList",list);
			
			req.getRequestDispatcher("carList.jsp").forward(req, resp);
		}else if("/carToAdd".equals(path)) {
			req.getRequestDispatcher("carAdd.jsp").forward(req, resp);
		}else if("/carDoAdd".equals(path)) {
			Car car=new Car();
			car.setC_id(Integer.parseInt(req.getParameter("c_id")));
			car.setC_name(req.getParameter("c_name"));
			car.setC_price(Integer.parseInt(req.getParameter("c_price")));
			
			service.addNewCar(car);
			
			resp.sendRedirect("carList");
		}else if("/carToUpd".equals(path)) {
			Car car=service.getCarById(req.getParameter("c_id"));
			
			req.setAttribute("car",car);
			
			req.getRequestDispatcher("carUpd.jsp").forward(req, resp);
			
		}else if("/carDoUpd".equals(path)) {
			Car car=new Car();
			car.setC_id(Integer.parseInt(req.getParameter("c_id")));
			car.setC_name(req.getParameter("c_name"));
			car.setC_price(Integer.parseInt(req.getParameter("c_price")));
			
			service.updCar(car);
			
			resp.sendRedirect("carList");
		}else if("/carDoDel".equals(path)) {
			
			String c_id=req.getParameter("c_id");
		
			service.delCar(c_id);
			
			resp.sendRedirect("carList");
			
			
		}
	}
	
	@Override
	protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		this.doGet(req, resp);
	}

}

3、数据库的连接DBUtils

package com.tnr.utils;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

public class DBUtils {
	private static final String driver="com.mysql.jdbc.Driver";
	private static final String url="jdbc:mysql://localhost:3306/cars";
	private static final String user="root";
	private static final String pwd="root";
	
	static {
		try {
			Class.forName(driver);
		} catch (ClassNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}
	
	Connection con=null;
	PreparedStatement pstm=null;
	ResultSet rs=null;
	//链接数据库
	public static  Connection getConnection() throws SQLException {
		return DriverManager.getConnection(url, user, pwd);
		
		
	}
	
	//关闭数据库
	public static void close(Connection con,PreparedStatement pstm,ResultSet rs) {
		
			try {
				if(rs!=null) {
					rs.close();
				}
			} catch (SQLException e) {
				throw new RuntimeException(e);
			}
			
			try {
				if(pstm!=null) {
					pstm.close();
				}
			} catch (SQLException e) {
				throw new RuntimeException(e);
			}
			
			try {
				if(con!=null && !con.isClosed()) {
					con.close();
				}
			} catch (SQLException e) {
				throw new RuntimeException(e);
			}
		
	}

}

4、需要一个简单的跳转页面

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>

<a href="carList">跳转</a>


</body>
</html>

5、需要一个主界面（主要就是对象的集合以及显示对象的列表）

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8" import="java.util.*,com.tnr.bean.*"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>

<body>
	<%List<Car> list=(List<Car>)request.getAttribute("carList"); %>

	<a href="carToAdd">新增</a>
	<table>
		<tr>
			<td>车辆的编号</td>
			<td>车辆的名称</td>
			<td>车辆的价格</td>
			<td>操作</td>
		</tr>
		
		<%
			for(Car cars:list){ 
		%>
			<tr>
				<td><%=cars.getC_id() %></td>
				<td><%=cars.getC_name() %></td>
				<td><%=cars.getC_price() %></td>
				
				<td>
				
					<a href="carToUpd?c_id=<%=cars.getC_id()%>">修改</a>
					<a href="carDoDel?c_id=<%=cars.getC_id()%>">删除</a>
				</td>
			
			</tr>
		
		
		<%
			}
		%>
	
	
	
	</table>

</body>
</html>

6、接下来就是简单增改的操作

//增加的页面
<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>

	<form action="carDoAdd" method="post">
		<div>
			车辆的编号：
			<input type="number" name="c_id"/>
		</div>
		<div>
			车辆的名称：
			<input type="text" name="c_name"/>
		</div>
		<div>
			车辆的价格：
			<input type="number" name="c_price"/>
		</div>
		<div>
			<input type="submit" value="提交"/>
		</div>
	
	
	</form>


</body>
</html>

//修改的页面
<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8" import="com.tnr.bean.*"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
	<%
	
		Car car=(Car)request.getAttribute("car");
	
	%>

	<form action="carDoUpd" method="post">
		<div>
			车辆的编号：
			<input type="number" readonly="readonly" name="c_id" value="<%=car.getC_id()%>"/>
		</div>
		<div>
			车辆的名称：
			<input type="text" value="<%=car.getC_name() %>" name="c_name"/>
		</div>
		<div>
			车辆的价格：
			<input type="number" value="<%=car.getC_price() %>" name="c_price"/>
		</div>
		<div>
			<input type="submit" value="提交"/>
		</div>
	
	
	</form>

</body>
</html>

写一个简单的增删改查

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