模拟设计一个使用于社区管理来人员登记的系统，采取Browser/Client结构，基于MVC设计开发
1. 项目准备 1.1 环境搭建- 开发工具使用Intellij IDEA 2021.3.1
- Java:version 17.0
- Mysql:Version 5.7
- Tomcat:9.0.58
- 使用JDBC驱动 mysql-connector-java.5.1.34.jar 和 javascript框架 Jquery包
使用Navicat 12 可视化编辑/新建数据库与表
新建一个数据库db_commnuicate 字符集采用utf-8
1.2.1 表设计设计新建一张表tb_person里面表设计如下:
1.2.2 添加测试数据向tb_person表中添加测试数据以备测试使用
测试sql语句代码如下:
INSERT INTO `tb_person` VALUES (1, 1, '喜羊羊', '男', '1992-05-06', '430405199205061234', '长沙市岳麓区街道123号', '1', '2022-03-20 22:09:07');
INSERT INTO `tb_person` VALUES (2, 2, '王喜顺', '男', '1998-07-18', '390304199807184321', '淄博市淄川区街道321号', '0', '2022-03-04 22:11:38');
INSERT INTO `tb_person` VALUES (3, 3, '刘二牛', '女', '1998-11-11', '43040519981111321X', '长沙市雨花区街道778号', '1', '2022-03-21 22:12:43');
建立一个新的Javaproject项目—勾选WebApplication 4.0框架支持变成一个动态web项目
下一步
下一步 添加WebApplication框架支持
finshed! 项目结构如下
1.3.1 创建包被Tomcat服务器所识别并且编译代码写在src文件里面，为了使用MVC方式开发时明确开发思路，必须将包与包之间的结构清清楚楚的分析到位,我们要创建以下包
- Controller (控制层)
- Dao (业务处理层)
- Model (数据模型层)
- Utils (工具类)
- View (视图层)
点击
Add Configuration添加Tomcat服务器选择Local
并在Deployment里添加artifact 并且将Application context 虚拟资源目录修改
1.3.2.1 向项目依赖中添加Tomcat在编写Serlvet类时不正确添加依赖会引起报错
2. 编码开发 2.1 Dao层与Utils工具类的实现 2.2.1 BaseDao类完成Dao层里的BaseDao类，BaseDao类主要完成Dao类里基本的业务处理 *** 作，其他Dao类通过继承来调用以下方法
代码如下:
package Dao;
import Utils.JDBCconnection;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
public class BaseDao {
private static Connection conn = null;
private static PreparedStatement ps = null;
private static ResultSet rs = null;
//初始化类时将数据库连接赋予变量conn
static {
if (conn != null ){
try {
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
conn = JDBCconnection.getConnection();
}
//执行基础查询语句
public static ResultSet executeQuery(String prepareSql , Object[]... param){
try {
ps = conn.prepareStatement(prepareSql);
if (param != null){
for (int i = 0 ; i < param.length ; i++){
ps.setObject(i+1,param[i]);
}
}
rs = ps.executeQuery();
return rs;
} catch (SQLException e) {
e.printStackTrace();
}
return rs;
}
//执行基础的增、删、改功能
public static int executeSQL(String prepareSql, Object[]... param){
int j = 0;
try {
ps = conn.prepareStatement(prepareSql);
if (param != null){
for (int i = 0 ; i < param.length ; i++){
ps.setObject(i+1,param[i]);
}
}
j = ps.executeUpdate();
return j;
} catch (SQLException e) {
e.printStackTrace();
}
return j;
}
}
完成Utils工具类里的JDBC连接类，完成底层连接数据库的 *** 作需要在依赖中添加mysql-connector-java 5.1.34.jar包 ，并且在WEB-INF-lib下添加jar包以便后续在服务器上运行能正确引用此jar包
代码如下:
package Utils;
import java.sql.*;
public class JDBCconnection {
private static final String Driver = "com.mysql.jdbc.Driver";
private static final String Url = "jdbc:mysql:///"; // 三个杠代表默认中间填写 localhost:3306 / 127.0.0.1:3306
private static final String User = "root";
private static final String Password = "123456";
public static Connection getConnection(){
try {
Class.forName(Driver);
return DriverManager.getConnection(Url,User,Password);
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
}
return null;
}
//释放资源方法 先关闭Resultset 其次statement 最后Connection
public static void Relesse(Connection conn , Statement statement) {
if(statement != null){
try {
statement.close();
} catch (SQLException e) {
e.printStackTrace();
}
statement = null;
}
if (conn != null){
try {
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
conn = null;
}
}
public static void Relesse(Connection conn , Statement statement , ResultSet rs) {
if(rs != null){
try {
rs.close();
} catch (SQLException e) {
e.printStackTrace();
}
rs = null;
}
Relesse(conn , statement);
}
}
接口PersonDao类
代码如下:
package Dao;
import Model.Person;
import java.sql.SQLException;
import java.util.List;
public interface PersonDao {
List getPersonList() throws SQLException;
int addPerson(Person person);
int delPerson(int personId);
}
实现类
代码如下:
package Dao;
import Model.Person;
import java.sql.Date;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Timestamp;
import java.util.ArrayList;
import java.util.List;
public class PersonDaoImpl extends BaseDao implements PersonDao{
private static ResultSet rs = null;
@Override
public List<Person> getPersonList() throws SQLException {
String sql = "select * from tb_person";
List<Person> list = new ArrayList<>();
rs = this.executeQuery(sql);
while (rs.next()){
Person p = new Person();
p.setId(rs.getInt("id"));
p.setNo(rs.getInt("no"));
p.setSex(rs.getString("sex"));
p.setName(rs.getString("name"));
p.setBirth(rs.getString("birth"));
p.setAddress(rs.getString("address"));
p.setCardId(rs.getString("cardID"));
p.setIsLocal(rs.getString("isLocal"));
p.setWriteTime(rs.getTimestamp("writeTime"));
list.add(p);
}
return list;
}
@Override
public int addPerson(Person person) throws SQLException {
Person p = new Person();
int no = 0 ;
String prepareSql = "INSERT INTO tb_person VALUES(null,?,?,?,?,?,?,?,?);";
String sql = "select * from tb_person ;";
rs = this.executeQuery(sql);
rs.last();
p.setNo(rs.getInt("id"));
person.setNo( p.getNo() + 1 );
person.setWriteTime(new Timestamp(System.currentTimeMillis()));
this.executeSQL("alter table tb_person auto_increment= ? ;", person.getNo()); //保持主键id 字段之间的递增 可保持序号不会乱
int i = this.executeSQL(prepareSql,person.getNo(),person.getName(),person.getSex(),person.getBirth(),person.getCardId(),person.getAddress(),person.getIsLocal(),person.getWriteTime());
return i;
}
@Override
public int delPerson(int personId) {
String prepareSql = "DELETE FROM tb_person where id = ?";
int i = this.executeSQL(prepareSql,personId);
return i;
}
}
通过IDEA里的DATABASE功能—Generate pojs‘s–生成数据模型类
代码如下:
package Model;
import java.io.Serializable;
import java.sql.Date;
import java.sql.Timestamp;
import java.util.Objects;
public class Person implements Serializable {
private int id;
private int no;
private String name;
private String sex;
private String birth;
private String cardId;
private String address;
private String isLocal;
private java.sql.Timestamp writeTime;
public Person() {
}
public Person(int id, int no, String name, String sex, String birth, String cardId, String address, String isLocal, Timestamp writeTime) {
this.id = id;
this.no = no;
this.name = name;
this.sex = sex;
this.birth = birth;
this.cardId = cardId;
this.address = address;
this.isLocal = isLocal;
this.writeTime = writeTime;
}
@Override
public String toString() {
return "Person{" +
"id=" + id +
", no=" + no +
", name='" + name + '\'' +
", sex='" + sex + '\'' +
", birth=" + birth +
", cardId='" + cardId + '\'' +
", address='" + address + '\'' +
", isLocal='" + isLocal + '\'' +
", writeTime=" + writeTime +
'}';
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (!(o instanceof Person)) return false;
Person person = (Person) o;
return id == person.id && no == person.no && Objects.equals(name, person.name) && Objects.equals(sex, person.sex) && Objects.equals(birth, person.birth) && Objects.equals(cardId, person.cardId) && Objects.equals(address, person.address) && Objects.equals(isLocal, person.isLocal) && Objects.equals(writeTime, person.writeTime);
}
@Override
public int hashCode() {
return Objects.hash(id, no, name, sex, birth, cardId, address, isLocal, writeTime);
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public int getNo() {
return no;
}
public void setNo(int no) {
this.no = no;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getSex() {
return sex;
}
public void setSex(String sex) {
this.sex = sex;
}
public String getBirth() {
return birth;
}
public void setBirth(String birth) {
this.birth = birth;
}
public String getCardId() {
return cardId;
}
public void setCardId(String cardId) {
this.cardId = cardId;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
public String getIsLocal() {
return isLocal;
}
public void setIsLocal(String isLocal) {
this.isLocal = isLocal;
}
public java.sql.Timestamp getWriteTime() {
return writeTime;
}
public void setWriteTime(java.sql.Timestamp writeTime) {
this.writeTime = writeTime;
}
}
主要负责调用Dao层与Model层，控制View层输出模型
代码如下:
package Controller;
import Dao.PersonDao;
import Dao.PersonDaoImpl;
import Model.Person;
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 javax.servlet.http.HttpSession;
import javax.servlet.jsp.PageContext;
import java.io.IOException;
import java.sql.Date;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
@WebServlet("/show")
public class personController extends HttpServlet {
private static PersonDao personDao = new PersonDaoImpl();
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
this.doGet(req,resp);
}
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
req.setCharacterEncoding("utf-8");
resp.setContentType("text/html;charset=utf-8");
HttpSession session = req.getSession();
List<Person> personList = new ArrayList<>();
String action = req.getParameter("action");
switch (action){
case "query":
try {
personList = personDao.getPersonList();
session.setAttribute("personList",personList);
} catch (SQLException e) {
e.printStackTrace();
}
req.getRequestDispatcher("View/main.jsp").forward(req,resp);
break;
case "del":
String id = req.getParameter("id");
personDao.delPerson(Integer.parseInt(id));
resp.sendRedirect(getServletContext().getContextPath()+"/show?action=query");
break;
case "insert":
try {
Person person = new Person();
person.setName(req.getParameter("name"));
person.setSex(req.getParameter("sex"));
person.setBirth((req.getParameter("birth")));
person.setAddress(req.getParameter("address"));
person.setCardId(req.getParameter("cardId"));
person.setIsLocal(req.getParameter("isLocal"));
personDao.addPerson(person);
resp.sendRedirect(getServletContext().getContextPath()+"/show?action=query");
} catch (SQLException e) {
e.printStackTrace();
}
break;
}
}
}
View文件下创建两个JSP文件 一个main.jsp展示数据 一个addPerson.jsp添加数据
index.jsp作为跳转页面
代码如下:
2.4.1 index.jsp<%--
Created by IntelliJ IDEA.
User: 10501
Date: 2022/3/20
Time: 21:24
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
$Title$
点击前往社区管理系统
<%@ page import="Model.Person" %>
<%@ page import="java.util.List" %><%--
Created by IntelliJ IDEA.
User: 10501
Date: 2022/3/21
Time: 12:52
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jstl/core_rt"%>
Title
<%-- <%--%>
<%-- List personList = (List) session.getAttribute("personList");--%>
<%-- %>--%>
社区人员登记系统
序号
姓名
性别
出生日期
身份z号
现住地
是否本地户口
登记时间
*** 作
删除登记
<%--
Created by IntelliJ IDEA.
User: 10501
Date: 2022/3/21
Time: 22:13
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
Title
新增登记人员
整体编码到此完毕!
3. 项目展示项目结构如下：
3.1 页面展示 3.1.1 main.jsp主要展示 3.1.2 addPerson.jsp主要展示 4. 总结总得来说这套系统代码并不难 难在于花时间总结经验与改进代码 总结一下犯下的小错误
-
本来想着将View层放在WEB-INF下通过Requset转发访问，但后面发现在删除完成处理页面刷新问题无法很好的重新加载数据，就推倒重来写成放在外面,结果上来说刷新页面重定向还是好用的 花了大量的时间研究 结论还是不要将请求处理的太麻烦
-
开发过程中遇到了OUT文件中发现没有更新WEB-INF下的文件夹，处理方法重新导入artifact工件 ,解决完成
-
表单上input标签Date类型从Request接收是String类型 所以在数据模型中 并不一定要Date类型的属性反而改成String类型的属性 会更好的处理保存数据
-
数据库表中处理主键ID断层问题 通过如下代码解决 先运行该代码再插入会解决主键断层问题
ALTER TABLE tb_person auto_increment = ? INSERT INTO tb_person VALUES(null); 插入的主键ID 根据上面问号所设置的值来插入
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