javaee实验：使用mvc模式设计一个图书管理系统

太多了把报告粘贴过来了，仅供参考

实习三 EL、JSTL及MVC
一、实习要求与目的
1.掌握标签库的使用
2.掌握EL及JSTL常用标签及方法
3.掌握MVC的编程模式，完成一个完整的信息管理系统
二、实习内容
使用EL、JSTL及MVC完成一个图书管理系统，要求完成图书信息的添加、修改、删除、查询与显示；并添加用户管理功能，只有登录用户才能完成图书的管理操作。
三、扩展
试着使用过滤器作为控制器完成实习内容。

四、实验代码
代码在最下面
工程结构如下图：

这个实验的工程结构中Model是cn.cie.dao和entity包中的dao层和实体类，Controller是一个过滤器和一个Servlet,其中Servlet主要是用作一个中间的统一控制，里面没有代码逻辑，代码逻辑主要都是通过过滤器实现，然后View就是几个jsp页面了。主要思路都比较清晰，其中有些细节需要注意，比如增加记录时id的自动设置等。

六、实验结果
1.登录控制
用户表中有一个用户

还未登录时直接访问/ctrl都会跳转到登录界面要求登录

登录成功后：

和数据库book表中的数据对应的上：

添加数据：

数据表中显示增加一条记录，id顺延：

修改图书信息：
把价格改为99

删除图书：
在图书对应的选项里点击删除选项即可删除图书信息：

数据表中的记录显示已经被删除

代码太多了，又不能直接发文件。。下面只粘控制器和dao层

工程放在仓库了：https://gitee.com/majun_real/mvc-library-management-system/tree/master

提示：所谓的id自动增长可以通过创建表定义列时设置，而本文是写了一个函数来获取最大id（原因是我写这个作业的时候不知道可以在数据表上设置自动增长。。。大家写的时候在只要对数据表的id字段设置自动增长就好了。。）

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"><modelVersion>4.0.0</modelVersion><groupId>org.example</groupId><artifactId>shiyan3</artifactId><version>1.0-SNAPSHOT</version><packaging>war</packaging><properties><maven.compiler.source>8</maven.compiler.source><maven.compiler.target>8</maven.compiler.target></properties><dependencies><dependency><groupId>javax.servlet</groupId><artifactId>javax.servlet-api</artifactId><version>4.0.0</version><scope>provided</scope></dependency><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>5.1.46</version></dependency><dependency><groupId>javax.servlet</groupId><artifactId>jstl</artifactId><version>1.2</version></dependency><dependency><groupId>junit</groupId><artifactId>junit</artifactId><version>4.13</version><scope>test</scope></dependency></dependencies><build><plugins><plugin><groupId>org.eclipse.jetty</groupId><artifactId>jetty-maven-plugin</artifactId><version>9.2.11.v20150529</version><configuration><webAppConfig><contextPath>/</contextPath></webAppConfig><httpConnector><port>80</port></httpConnector></configuration></plugin></plugins></build>
</project>

MyCtrlFilter.java

package cn.cie.controlles;import cn.cie.dao.BookDao;
import cn.cie.dao.UserDao;
import cn.cie.entity.Book;
import cn.cie.entity.User;import javax.servlet.*;
import javax.servlet.annotation.*;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.List;@WebFilter(filterName = "MyCtrlFilter",urlPatterns ={"/ctrl"})
public class MyCtrlFilter implements Filter {public void init(FilterConfig config) throws ServletException {}public void destroy() {}@Overridepublic void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws ServletException, IOException {HttpServletRequest request1=(HttpServletRequest) request;HttpServletResponse response1=(HttpServletResponse) response;String user = request.getParameter("user");String password = request.getParameter("password");String sessionuser=(String) request1.getSession().getAttribute("user");UserDao userDao=new UserDao();if(user==null){if(sessionuser==null)//之前没有登录过{request1.getSession().setAttribute("err","还未登陆，请登陆");response1.sendRedirect("login.jsp");return;}}else //从login.jsp访问{//是否勾选记住密码，写cookieString memory=request.getParameter("memory");if(memory!=null){Cookie c1=new Cookie("user",user);Cookie c2=new Cookie("password",password);response1.addCookie(c1);response1.addCookie(c2);}//判断用户名和密码boolean flag=false;try {List<User> users=userDao.listuser();for (User u:users) {if (u.getUser().equals(user)){if(u.getPassword().equals(password)){   //用户名和密码都正确flag=true;request1.getSession().setAttribute("user",user);break;}}}} catch (Exception e) {e.printStackTrace();request1.setAttribute("errMsg",e.getMessage());request1.getRequestDispatcher("error.jsp").forward(request1,response1);} if(flag==false){request1.getSession().setAttribute("err","用户名或密码错误");response1.sendRedirect("login.jsp");return;}}String act = request1.getParameter("act");BookDao bookDaodao = new BookDao();try{if("list".equals(act)){List<Book> books = bookDaodao.list();request1.setAttribute("books",books);request1.getRequestDispatcher("list.jsp").forward(request1,response1);}else if("add".equals(act)) {request1.getRequestDispatcher("edit.jsp").forward(request1,response1);}else if("edit".equals(act)) {String ids = request1.getParameter("id");Integer id = Integer.parseInt(ids);Book book = bookDaodao.getById(id);request1.setAttribute("book",book);request1.getRequestDispatcher("edit.jsp").forward(request1,response1);}else if("save".equals(act)) {String tuh = request1.getParameter("tuh");String name = request1.getParameter("name");String className = request1.getParameter("book_type");String scorces = request1.getParameter("price");Float sc = Float.parseFloat(scorces);Book book = new Book();String id = request1.getParameter("id");if(id != null && !"".equals(id)){//id非空是对已存在记录编辑的情况Integer ids = Integer.parseInt(id);book.setId(ids);}book.settuh(tuh);book.setName(name);book.setbook_type(className);book.setprice(sc);bookDaodao.insertOrUpdate(book);response1.sendRedirect("ctrl?act=list");}else if("delete".equals(act)) {String ids = request1.getParameter("id");Integer id = Integer.parseInt(ids);bookDaodao.deleteById(id);response1.sendRedirect("ctrl?act=list");}else {throw  new Exception("非法请求！！");}}catch (Exception e){e.printStackTrace();request1.setAttribute("errMsg",e.getMessage());request1.getRequestDispatcher("error.jsp").forward(request1,response1);}//chain.doFilter(request1, response1);}
}

Servlet.java
没啥东西，就是借他的路径中转一下

package cn.cie.controlles;import javax.servlet.*;
import javax.servlet.http.*;
import javax.servlet.annotation.*;
import java.io.IOException;@WebServlet(name = "Servlet", value = "/ctrl")
public class Servlet extends HttpServlet {@Overrideprotected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {}@Overrideprotected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {}
}

BaseDao.java

package cn.cie.dao;import java.sql.*;public class BaseDao {static String driverName = "com.mysql.jdbc.Driver";static String url =  "jdbc:mysql://localhost/mvc?characterEncoding=utf8&useSSL=false&serverTimezone=Asia/Shanghai";static String userName = "root";static String passwd = "";static Connection con = null;void getCon() throws ClassNotFoundException, SQLException {//okClass.forName(driverName);if(con == null || con.isClosed()){con = DriverManager.getConnection(url,userName,passwd);}}protected ResultSet select(String sql) throws SQLException, ClassNotFoundException {//okgetCon();Statement stat = con.createStatement();ResultSet rs = stat.executeQuery(sql);return rs;}protected ResultSet select(String sql, Object[] params) throws SQLException, ClassNotFoundException {//okgetCon();PreparedStatement pstat = con.prepareStatement(sql);for(int i = 1; i <= params.length; i++){pstat.setObject(i,params[i - 1]);}ResultSet rs = pstat.executeQuery();return rs;}protected int save(String sql,Object[] params) throws SQLException, ClassNotFoundException {//okgetCon();PreparedStatement pstat = con.prepareStatement(sql);for(int i = 1; i <= params.length; i++){pstat.setObject(i,params[i - 1]);}int rs = pstat.executeUpdate();pstat.close();return rs;}protected int getNewid()throws SQLException, ClassNotFoundException //zijixiede{getCon();Statement stat = con.createStatement();ResultSet rs = stat.executeQuery("select  max(id) id from book ");if(!rs.next()) return 1;//当前表中没有数据return  rs.getInt(1)+1;//取第一列的数据，即最大的id}void closeCon(){//oktry {con.close();} catch (SQLException throwables) {throwables.printStackTrace();}}
}

BookDao.java

package cn.cie.dao;import cn.cie.entity.Book;import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;public class BookDao extends BaseDao {static String SELECT = "select * from book";static String SELECTBYID = "select * from book where id=?";static String INSERT = "insert into book set tuh=?,name=?,book_type=?,price=?,id=?";static String UPDATE = "update book set tuh=?,name=?,book_type=?,price=? where id=?";static String DELETE = "delete from book where id = ?";public List<Book> list() throws SQLException, ClassNotFoundException {List<Book> books = new ArrayList<>();ResultSet rs = select(SELECT);while (rs.next()){Book book = new Book();book.setId(rs.getInt("id"));book.settuh(rs.getString("tuh"));book.setName(rs.getString("name"));book.setbook_type(rs.getString("book_type"));book.setprice(rs.getFloat("price"));books.add(book);}rs.close();return books;}public void insertOrUpdate(Book book) throws SQLException, ClassNotFoundException {Object[] params = new Object[5];params[0] = book.gettuh();params[1] = book.getName();params[2] = book.getbook_type();params[3] = book.getprice();if(book.getId() == null){//插入的情况，需要加idparams[4]=Integer.valueOf(getNewid());save(INSERT,params);}else {//更新的情况params[4]=book.getId();save(UPDATE,params);}}public void deleteById(Integer id) throws SQLException, ClassNotFoundException {Object[] params = new Object[1];params[0] = id;save(DELETE,params);}public Book getById(Integer id) throws SQLException, ClassNotFoundException {//okObject[] params = new Object[1];params[0] = id;ResultSet rs = select(SELECTBYID,params);rs.next();Book book = new Book();book.setId(rs.getInt("id"));book.settuh(rs.getString("tuh"));book.setName(rs.getString("name"));book.setbook_type(rs.getString("book_type"));book.setprice(rs.getFloat("price"));return book;}}

UserDao.java

package cn.cie.dao;import cn.cie.entity.User;import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;public class UserDao extends BaseDao {static String SELECTUSER = "select * from usertable";public List<User> listuser() throws SQLException, ClassNotFoundException{List<User> users = new ArrayList<>();ResultSet rs = select(SELECTUSER);while (rs.next()){User user = new User();user.setUser(rs.getString("user"));user.setPassword(rs.getString("password"));users.add(user);}rs.close();return users;}
}

Book.java

package cn.cie.entity;public class Book {private Integer id;private String tuh;private String name;private String book_type;private Float price;@Overridepublic String toString() {return "Book{" +"id=" + id +", tuh='" + tuh + '\'' +", name='" + name + '\'' +", book_type='" + book_type + '\'' +", price=" + price +'}';}public String gettuh() {return tuh;}public void settuh(String tuh) {this.tuh = tuh;}public Integer getId() {return id;}public void setId(Integer id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}public String getbook_type() {return book_type;}public void setbook_type(String book_type) {this.book_type = book_type;}public Float getprice() {return price;}public void setprice(Float price) {this.price = price;}}

User.java

package cn.cie.entity;public class User {private String user;private String password;public String getUser() {return user;}public void setUser(String user) {this.user = user;}public String getPassword() {return password;}public void setPassword(String password) {this.password = password;}
}