《注册V1.1》——————加入了查询数据库中的学生表，解决了中文乱码问题，以及一个Servlet解决多个请求的问题

程序员文章站 2024-03-20 13:51:10

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1.准备工作

在数据库中创建数据库和注册表，导入jar包，c3p0的配置文件，以及c3p0和日期转换工具类，登录的里面都已经上传过c3p0的配置文件，以及c3p0和日期转换工具类的代码。

2.注册页面

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
	<form action="StudentServlet" method="post">
	<input type="hidden" name="fun" value="add" />
		<table  width="70%" align="center">
			<tr>
				<td>name</td>
				<td>
					<input type="text" name="name"/>
				</td>
			</tr>
			<tr>
				<td>age</td>
				<td>
					<input type="text" name="age"/>
				</td>
			</tr>
			<tr>
				<td>birthday</td>
				<td>
					<input type="text" name="birthday"/>
				</td>
			</tr>
			<tr>
				<td colspan=2>
					<input type="submit" value="register"/>
				</td>
			</tr>
		</table>
	</form>
</body>
</html>

注册结果跳转的页面

2.1成功

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<h1>注册成功</h1>
</body>
</html>

2.2失败

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<h1>注册成功</h1>
</body>
</html>

3.查询页面

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<a href="StudentServlet?fun=findall">查询全部学生</a>
</body>
</html>

查询结果展示

package com.offcn.servlet;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.List;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.offcn.bean.Student;

public class ViewStudentServlet extends HttpServlet {

	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		List<Student> list = (List<Student>)request.getAttribute("studentList");
		
		response.setContentType("text/html;charset=utf-8");
		
		PrintWriter out = response.getWriter();
		out.print("<table align='center' width='70%' cellspacing='0' border='1px'>");
		out.print("<tr><th>ID</th><th>NAME</th><th>AGE</th><th>BIRTHDAY</th></tr>");
		for(Student stu : list){
			out.print("<tr><td>"+stu.getId()+"</td><td>"+stu.getName()+"</td><td>"+stu.getAge()+"</td><td>"+stu.getBirthday()+"</td></tr>");
		}
		out.print("</table>");
	}

	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		this.doGet(request, response);
	}

}

4.实体类

package com.offcn.bean;

import java.util.Date;

public class Student {
	private int id;
	private String name;
	private int age;
	private Date birthday;
	
	public Student(){}
	public Student(int id, String name, int age, Date birthday) {
		super();
		this.id = id;
		this.name = name;
		this.age = age;
		this.birthday = birthday;
	}
	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 int getAge() {
		return age;
	}
	public void setAge(int age) {
		this.age = age;
	}
	public Date getBirthday() {
		return birthday;
	}
	public void setBirthday(Date birthday) {
		this.birthday = birthday;
	}
	
}

5.操作数据库

package com.offcn.dao;

import java.util.List;

import com.offcn.bean.Student;

public interface StudentDao {
	public int insertStudent(Student stu);
	public List<Student> findAllStudent();
}

package com.offcn.dao.impl;

import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.BeanListHandler;

import com.offcn.bean.Student;
import com.offcn.dao.StudentDao;
import com.offcn.utils.C3P0Utils;

public class StudentDaoImpl implements StudentDao {

	public int insertStudent(Student stu) {
		int result = 0;
		
		QueryRunner qr = new QueryRunner(C3P0Utils.getDataSource());
		
		String sql = "insert into Student values(null,?,?,?) ";
		
		try {
			result = qr.update(sql,new Object[]{stu.getName(),stu.getAge(),stu.getBirthday()});
		} catch (SQLException e) {
			e.printStackTrace();
		}
		return result;
	}

	public List<Student> findAllStudent() {
		List<Student> list = new ArrayList<>();
		QueryRunner qr = new QueryRunner(C3P0Utils.getDataSource());
		String sql = "select * from student";
		try {
			list = qr.query(sql, new BeanListHandler<>(Student.class));
		} catch (SQLException e) {
			e.printStackTrace();
		}
		return list;
	}

}

6、程序入口

package com.offcn.servlet;

import java.io.IOException;
import java.util.List;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.offcn.bean.Student;
import com.offcn.dao.StudentDao;
import com.offcn.dao.impl.StudentDaoImpl;
import com.offcn.utils.DateUtil;

public class StudentServlet extends HttpServlet {

	protected void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		this.doPost(request, response);
	}

	protected void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		
		request.setCharacterEncoding("UTF-8");

		String fun = request.getParameter("fun");

		if ("add".equals(fun)) {
			add(request, response);
		}else if("findall".equals(fun)){
			findall(request,response);
		}

	}

	protected void add(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		String name = request.getParameter("name");
		String age = request.getParameter("age");
		String birthday = request.getParameter("birthday");

		Student stu = new Student();
		stu.setName(name);
		stu.setAge(Integer.parseInt(age));
		stu.setBirthday(DateUtil.stringToDate(birthday));

		StudentDao dao = new StudentDaoImpl();
		int result = dao.insertStudent(stu);
		if (result > 0) {
			request.getRequestDispatcher("success.html").forward(request, response);
		} else {
			//该需求重定向较好,因为转发地址栏不变,没刷新一次就存入一条数据到数据库
			response.sendRedirect("fail.html");
		}
	}
	
	protected void findall(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		StudentDao dao = new StudentDaoImpl();
		List<Student> list = dao.findAllStudent();
		
		request.setAttribute("studentList", list);
		request.getRequestDispatcher("ViewStudentServlet").forward(request, response);
	}
}