JDBC与JSP初识
主要内容：
-JDBC 三层架构进行组织后台代码
-JSP初识
- 在页面展示表中数据
- 在页面输入数据并处理数据
课堂参考代码：
1、后台代码：
（1）cn.sdut.dao. BaseDao.java
package cn.sdut.dao;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
public class BaseDao {
// 1 定义数据库访问公共变量
Connection con;
PreparedStatement pst;
ResultSet rs;
// 2 定义数据库的连接方法
public Connection getConn() {
try {
// 1 加载JDBC驱动程序
Class.forName("com.mysql.jdbc.Driver");
// 2 得到数据库的连接
String url = "jdbc:mysql://localhost:3306/school?useUnicode=true&characterEncoding=utf-8";
con = DriverManager.getConnection(url, "root", "usbw");
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return con;
}
// 3 关闭conn,pst,rs
public void closeAll() {
try {
if (rs != null) {
rs.close();
}
if(pst!=null)
{
pst.close();
}
if(con!=null)
{
con.close();
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}（2）cn.sdut.dao.StudentDao.java
package cn.sdut.dao;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;
import cn.sdut.po.Student;
public class StudentDao extends BaseDao{
// 增
public int add(Student stu) {
int result = 0;
try {
con=getConn();
String sql="insert into student(name,birthday,score) values(?,?,?)";
pst=con.prepareStatement(sql);
pst.setString(1,stu.getName());
pst.setString(2, stu.getBirthday());
pst.setFloat(3, stu.getScore());
result=pst.executeUpdate();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
finally
{
closeAll();
}
return result;
}
// 删除
public int del(int id) {
int result = 0;
try {
con=getConn();
String sql="delete from student where id=?";
pst = con.prepareStatement(sql);
pst.setInt(1, id);
// 5 执行SQL语句
result=pst.executeUpdate();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
finally
{
closeAll();
}
return result;
}
// 修改
public int update(Student stu) {
int result = 0;
try {
con=getConn();
String sql="update student set name=’"+stu.getName()+"’ where id="+stu.getId();
pst=con.prepareStatement(sql);
result=pst.executeUpdate(sql);
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
finally
{
closeAll();
}
return result;
}
// 查询记录
public List queryAll() {
List list = new ArrayList();
try {
con=getConn();
String sql="select * from student";
pst=con.prepareStatement(sql);
rs=pst.executeQuery(sql);
while(rs.next())
{
Student stu=new Student();
stu.setId(rs.getInt(1));
stu.setName(rs.getString(2));
stu.setBirthday(rs.getString(3));
stu.setScore(rs.getFloat(4));
list.add(stu);
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
finally
{
closeAll();
}
return list;
}
}
（3）cn.sdut.po.Student.java
package cn.sdut.po;
public class Student {
private int id;
private String name;
private String birthday;
private float score;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getBirthday() {
return birthday;
}
public void setBirthday(String birthday) {
this.birthday = birthday;
}
public float getScore() {
return score;
}
public void setScore(float score) {
this.score = score;
}
@Override
public String toString() {
return "Student [id=" + id + ", name=" + name + ", birthday="
+ birthday + ", score=" + score + "]";
}
}2、前端页面
（1）WebRoot/index.jsp
<%@page import="cn.sdut.po.Student"%>
<%@page import="cn.sdut.dao.StudentDao"%>
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme() + "://"
+ request.getServerName() + ":" + request.getServerPort()
+ path + "/";
%>
<%
StudentDao studentDao=new StudentDao();
List stuList=studentDao.queryAll();
%>
<html>
<head>
<base href="<%=basePath%>"
<title>My JSP ’index.jsp’ starting pagetitle>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
head>
<body>
<table border="1">
<tr align="center">
<td width="50">序号td>
<td width="50">姓名td>
<td width="100">出生年月td>
<td width="50">成绩td>
tr>
<%
for(Student stu:stuList)
{
out.print("");
out.print("");
out.print(stu.getId());
out.print(" ");
out.print("");
out.print(stu.getName());
out.print(" ");
out.print("");
out.print(stu.getBirthday());
out.print(" ");
out.print("");
out.print(stu.getScore());
out.print(" ");
out.print(" ");
}
%>
table><br><br>
<a href="addStudent.jsp" >增加学生a>
body>
html>（2）WebRoot/addStudent.jsp
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme() + "://"
+ request.getServerName() + ":" + request.getServerPort()
+ path + "/";
%>
<html>
<head>
<base href="<%=basePath%>">
<title>My JSP ’addStudent.jsp’ starting pagetitle>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
head>
<body>
<form action="doAdd.jsp" method="post">
<table>
<caption>增加学生caption>
<tr>
<td width="97" align="center">姓 名:td>
<td width="175"><input type="text" name="name"/>td>
tr>
<tr>
<td align="center">出生年月:td>
<td><input type="text" name="birthday"/>td>
tr>
<tr>
<td align="center">成 绩:td>
<td><input type="text" name="score"/>td>
tr>
<tr align="center"><td height="55" colspan="2">
<input type="submit" value="确定"/>
<input type="reset" value="取消"/>
td> tr>
table>
form>
body>
html>（3）WebRoot/doAdd.jsp
<%@page import="cn.sdut.dao.StudentDao"%>
<%@page import="cn.sdut.po.Student"%>
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<html>
<head>
<base href="<%=basePath%>">
<title>My JSP ’doAdd.jsp’ starting pagetitle>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
head>
<%
//1 接受客户端传来的数据并封装成Student类的对象
request.setCharacterEncoding("utf-8");
String name=request.getParameter("name");
String birthday=request.getParameter("birthday");
String score1=request.getParameter("score");
float score=Float.parseFloat(score1);
Student student=new Student();
student.setName(name);
student.setBirthday(birthday);
student.setScore(score);
//2 调用StudentDao的add方法,向数据库表中增 加记录
StudentDao studentDao=new StudentDao();
studentDao.add(student);
//3 转向index.jsp,展示最新的表中的数据
response.sendRedirect("index.jsp");
%>
<body>
body>
html>