java web 入门实例servlet篇（显示后台数据库列表，删除某一条记录并显示）

编写过程中需要注意的问题：

1.建立eclipse动态web工程时，需要改写编译后class文件的位置，通常情况下是这个位置：/WebContent/WEB-INF/classes

2.配置的页面链接和servlet类之间有两种方式：

1）通过在web.xml文件中进行配置：示例如下

<?xml version="1.0" encoding="UTF-8"?>

<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">

  <display-name>jspshow1</display-name>

  <servlet>

   <servlet-name>listTheStudent</servlet-name>

   <servlet-class>com.guodiantong.javaweb.ListTheStudent</servlet-class>

  </servlet>

  <servlet-mapping>

  <servlet-name>listTheStudent</servlet-name>

  <url-pattern>/list</url-pattern>

  </servlet-mapping>

  <servlet>

  <servlet-name>deleteTheStudent</servlet-name>

  <servlet-class>com.guodiantong.javaweb.DeleteServlet</servlet-class>

  </servlet>

  <servlet-mapping>

  <servlet-name>deleteTheStudent</servlet-name>

  <url-pattern>/delete</url-pattern>

  </servlet-mapping>

</web-app>

2）通过在eclipse新建servlet时，自动指示设置页面请求和servlet类之间的链接关系：如下图所示

new--->servlet

这种也能实现请求和对应的servlet类之间的映射，通过这种方式你会发下，tomcat使用的注解的方式@WebServlet，这种方式在web.xml文件中并没有通过 1）的那种方式显现出来

谈完上述注意的地方，下面开始见工程：先看下项目的目录结构

先看下所有的jsp文件：test.jsp文件

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"

    pageEncoding="ISO-8859-1"%>

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">

<html>

<head>

<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">

<title>Insert title here</title>

</head>

<body>

<a href="list">list all students</a>

</body>

</html>

　　students.jsp文件：

<%@ page language="java" contentType="text/html; charset=UTF-8"

    pageEncoding="UTF-8"%>

    <%@ page import="java.util.List" %>

<%@page import="com.guodiantong.javaweb.*" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">

<html>

<head>

<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">

<title>Insert title here</title>

</head>

<body>

<%=request.getAttribute("students") %>

<br>

<%

  List<Student> stus=(List<Student>)request.getAttribute("students");

%>

<table>

<tr>

  <th>flowid</th>

  <th>type</th>

  <th>id_card</th>

  <th>exam_card</th>

  <th>studentname</th>

  <th>location</th>

  <th>grade</th>

  <th>操作</th>

  <%

      for(Student student:stus){

   %>

	<tr>

	   <td><%=student.getFlowid() %></td>

	   <td><%=student.getType() %></td>

	   <td><%=student.getIdcard() %></td>

	   <td><%=student.getExam_card() %></td>

	   <td><%=student.getStudentname() %></td>

	   <td><%=student.getLocation() %></td>

	   <td><%=student.getGrade() %></td>

	   <td><a href="delete?flowid=<%=student.getFlowid() %>">删除</a></td>

	</tr>  

<%

    }

%>

</table>

</body>

</html>

success.jsp文件：

<%@ page language="java" contentType="text/html; charset=UTF-8"

    pageEncoding="UTF-8"%>

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">

<html>

<head>

<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">

<title>Insert title here</title>

</head>

<body>

  操作成功！！

  <a href="list">refresh</a>

</body>

</html>

　　下面是servlet类的代码：List请求对应的servlet类：ListTheStudent.java

package com.guodiantong.javaweb;

import java.io.IOException;

import java.util.ArrayList;

import java.util.List;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

public class ListTheStudent extends HttpServlet {

    @Override

    protected void doGet(HttpServletRequest request, HttpServletResponse response)

            throws ServletException, IOException {

        List<Student> students=new ArrayList<Student>();

        StudentDao studentDao=new StudentDao();

        students=studentDao.getAll();

        request.setAttribute("students", students);

        request.getRequestDispatcher("/students.jsp").forward(request, response);

    }

}

delete请求对应的jservlet java类：DeleteServlet.java

package com.guodiantong.javaweb;

import java.io.IOException;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

public class DeleteServlet extends HttpServlet {

    @Override

    protected void doGet(HttpServletRequest request, HttpServletResponse response)

            throws ServletException, IOException {

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

    StudentDao studentDao=new StudentDao();

    studentDao.deleteStudent(flowid);

    request.getRequestDispatcher("/success.jsp").forward(request, response);

    }

}

项目中最重要的StudentDao.java

package com.guodiantong.javaweb;

import java.sql.Connection;

import java.sql.DriverManager;

import java.sql.PreparedStatement;

import java.sql.ResultSet;

import java.sql.SQLException;

import java.util.ArrayList;

import java.util.List;

public class StudentDao {

public   List<Student>  getAll(){

    Connection connection=null;

    PreparedStatement preparedStatement=null;

    ResultSet resultSet=null;

    List<Student> students=new ArrayList<Student>();

   try {

       String driverClass="com.mysql.jdbc.Driver";

       String url="jdbc:mysql:///dsm";

       String user="root";

       String password="12345678";

       Class.forName(driverClass);

    connection=DriverManager.getConnection(url, user, password);

    String sql="SELECT flow_id,Type,id_card,exam_card,student_name,location,grade "

            +"FROM examstudent";

    preparedStatement=connection.prepareStatement(sql);

    resultSet=preparedStatement.executeQuery();

    while(resultSet.next()){

        String flowid=resultSet.getString(1);

        System.out.println(flowid);

        String type=resultSet.getString(2);

        String idcard=resultSet.getString(3);

        String exam_card=resultSet.getString(4);

        String studentname=resultSet.getString(5);

        String location=resultSet.getString(6);

        String grade=resultSet.getString(7);

        Student student=new Student(flowid, type, idcard, exam_card,

                studentname, location, grade);

        students.add(student);

    }

} catch (Exception e) {

    e.printStackTrace();

}finally{

    try {

        if(resultSet !=null){

            resultSet.close();

        }

    } catch (SQLException e) {

        // TODO Auto-generated catch block

        e.printStackTrace();

    }

    try {

        if(preparedStatement !=null){

            preparedStatement.close();

        }

    } catch (SQLException e) {

        // TODO Auto-generated catch block

        e.printStackTrace();

    }

    try {

        if(connection !=null){

            connection.close();

        }

    } catch (SQLException e) {

        // TODO Auto-generated catch block

        e.printStackTrace();

    }

}

    return students;

}

public   void  deleteStudent(String flowid){

    Connection connection=null;

    PreparedStatement preparedStatement=null;

   try {

       String driverClass="com.mysql.jdbc.Driver";

       String url="jdbc:mysql:///dsm";

       String user="root";

       String password="12345678";

       Class.forName(driverClass);

    connection=DriverManager.getConnection(url, user, password);

    String sql="DELETE FROM examstudent where flow_id=?";

    preparedStatement=connection.prepareStatement(sql);

    preparedStatement.setString(1, flowid);

    preparedStatement.execute();

} catch (Exception e) {

    e.printStackTrace();

}finally{

    try {

        if(preparedStatement !=null){

            preparedStatement.close();

        }

    } catch (SQLException e) {

        // TODO Auto-generated catch block

        e.printStackTrace();

    }

    try {

        if(connection !=null){

            connection.close();

        }

    } catch (SQLException e) {

        // TODO Auto-generated catch block

        e.printStackTrace();

    }

}

}

}

项目中的javabean ：Student.java

package com.guodiantong.javaweb;

public class Student {

private String flowid;

private String type;

private String idcard;

private String exam_card;

private String studentname;

private String location;

private String grade;

public String getFlowid() {

    return flowid;

}

public void setFlowid(String flowid) {

    this.flowid = flowid;

}

public String getType() {

    return type;

}

public void setType(String type) {

    this.type = type;

}

public String getIdcard() {

    return idcard;

}

public void setIdcard(String idcard) {

    this.idcard = idcard;

}

public String getExam_card() {

    return exam_card;

}

public void setExam_card(String exam_card) {

    this.exam_card = exam_card;

}

public String getStudentname() {

    return studentname;

}

public void setStudentname(String studentname) {

    this.studentname = studentname;

}

public String getLocation() {

    return location;

}

public void setLocation(String location) {

    this.location = location;

}

public String getGrade() {

    return grade;

}

public void setGrade(String grade) {

    this.grade = grade;

}

public Student() {

    super();

}

public Student(String flowid, String type, String idcard, String exam_card,

        String studentname, String location, String grade) {

    super();

    this.flowid = flowid;

    this.type = type;

    this.idcard = idcard;

    this.exam_card = exam_card;

    this.studentname = studentname;

    this.location = location;

    this.grade = grade;

}

@Override

public String toString() {

    return "Student [flowid=" + flowid + ", type=" + type + ", idcard="

            + idcard + ", exam_card=" + exam_card + ", studentname="

            + studentname + ", location=" + location + ", grade=" + grade + "]";

}

}

提到javabean就需要看一下后台数据表格的结构：

就是这些！！

java web 入门实例servlet篇（显示后台数据库列表，删除某一条记录并显示）的更多相关文章

java web学习笔记-Servlet篇
Servlet基础 1.Servlet概述 JSP的前身就是Servlet.Servlet就是在服务器端运行的一段小程序.一个Servlet就是一个Java类,并且可以通过“请求-响应”编程模型来访问 ...
3 Java Web 入门 1 Servlet 入门
1 Tomcat 1.1 安装 JDK Oracle 官网 1.2 安装 Tomcat
Java web 入门知识及HTTP协议详解
Java web 入门知识及HTTP协议详解 WEB入门 WEB,在英语中web即表示网页的意思,它用于表示Internet主机上供外界访问的资源. Internet上供外界访问的Web资 ...
Java Web入门经典扫描版
全书共分4篇19章,其中,第一篇为“起步篇”,主要包括开启JavaWeb之门.不可不知的客户端应用技术.驾驭JavaWeb开发环境.JavaWeb开发必修课之JSP语法等内容:第二篇为“核心篇”,主要 ...
Java快速入门-02-基础篇
Java快速入门-02-基础篇上一篇应该已经让0基础的人对 Java 有了一些了解,接一篇更进一步使用 Eclipse 快捷键这个老师一般都经常提,但是自己不容易记住,慢慢熟练快捷键快捷键作 ...
Java快速入门-01-基础篇
Java快速入门-01-基础篇如果基础不好或者想学的很细,请参看:菜鸟教程-JAVA 本笔记适合快速学习,文章后面也会包含一些常见面试问题,记住快捷键操作,一些内容我就不转载了,直接附上链接,嘻嘻 ...
java rmi 入门实例
java rmi 入门实例 (2009-06-16 16:07:55) 转载▼ 标签: java rmi 杂谈分类: java-基础 java rmi即java远程接口调用,实现了2台虚拟机之 ...
Javaweb项目-下拉列表显示后台数据库的数据
下面将演示前端下拉列表显示后台数据库中class表的说有班级的名称环境: Tomcat-8.5.40 mysql-8.0.13 eclipse-4.9.0 springmvc框架一.从mysql中 ...
MariaDB——显示所有数据库列表
显示所有数据库列表:其中,information_schema.performance_schema.test.mysql,这4个库表是数据库系统自带的表,一般不放数据. 进入某个库切换库,并显示库 ...

随机推荐

array numpy 模块
高级用法:http://www.jb51.net/article/87987.htm from array import * 调用 array 与 import numpy as np 调用 np. ...
oracle 网络环境配置
PLSQL Developer连接Oracle11g 64位数据库配置详解最近换了台64bit的电脑,所以oracle数据库也跟着换成了64bit的,不过问题也随之产生,由于plsql devel ...
Mycat入门及简单规则
以下都来自网络: 官网: http://www.mycat.io/ 官网配置文件解析: https://github.com/MyCATApache/Mycat-Server/wiki/9.0-%E6 ...
获取RequestMapping注解中的属性
参考:https://www.cnblogs.com/2013jiutian/p/7294053.html @RequestMapping("/value1") @Controll ...
php71 gdnz
更新yum库:yum updat yum install epel-release yum install -y gcc gcc-c++ autoconf libjpeg libjpeg-devel ...
ubuntu 下当前网速查看
ubuntu下用ethstatus可以监控实时的网卡带宽占用.这个软件能显示当前网卡的 RX 和 TX 速率,单位是Byte 一.安装 ethstatus 软件 #sudo apt-get insta ...
全国省市区数据库SQL(有可能不是最新的)
百度云下载地址:https://pan.baidu.com/s/1lStN7tYpwOtpC-r3G2X2sw
SSL - 简介
一.密码技术要了解SSL协议,首先要了解:加密算法.消息摘要算法(又称为哈希算法Hash),数字签名等概念.这些技术每个都可以写出一整本的书,它们结合在一起,提供了保密性.完整性和身份验证的功能. ...
qt基本类
多firstpage secondpage thirdpage fouthpage 实现多页面 xml解析实现按钮和 slot实现 mysql数据库访问实现
2018.07.25 bzoj3878: [Ahoi2014&Jsoi2014]奇怪的计算器（线段树）
传送门线段树综合. 让我想起一道叫做siano" role="presentation" style="position: relative;"&g ...

java web 入门实例servlet篇（显示后台数据库列表，删除某一条记录并显示）

java web 入门实例servlet篇（显示后台数据库列表，删除某一条记录并显示）的更多相关文章

随机推荐

热门专题