思维导图
一、 导jar包
导出mvc.jar
利用之前自定义的MVC的framework右键-->Export-->导出mvc.jar包
?导入项目所需jar包
二、 配置web.xml
如下：
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" id="WebApp_ID" version="3.1">
? <display-name>DHM_xml</display-name>
?<servlet>
?<servlet-name>DHM</servlet-name>
?<servlet-class>com.DHM.framework.DispatchServlet</servlet-class>
?<init-param>
?<param-name>configurationLocation</param-name>
?<param-value>/DHM.xml</param-value>
?</init-param>
?
?</servlet>
?<servlet-mapping>
?<servlet-name>DHM</servlet-name>
?<url-pattern>*.action</url-pattern>
?</servlet-mapping>
</web-app>
三、增删改查
?增删改最终都要跳回查询页面
?分析增删改查一共有多少结果集的配置
?查询：BookList.jsp ? 返回list
?增删改确定：book.action?methodName=list ? 返回：toList
?增加修改跳转对应页面：bookEdit.jsp ? 返回：toEdit
? ① DHM.xml:
<?xml version="1.0" encoding="UTF-8"?>
<config>
<!--
在这里每加一个配置，就相当于actions.put("/goods", new GoodsAction());
这样就解决了代码灵活性的问题 false-转发 /增删改true-重定向
-->
<action type="com.DHM.web.BookAction" path="/book">
<forward path="/bookList.jsp" redirect="false" name="list"/>
<forward path="/book.action?methodName=list" redirect="true" name="toList"/>
<forward path="/bookEdit.jsp" redirect="false" name="toEdit"/>
</action>
</config>②通用增删改
增删改查的通用套路
?? ?1、建立连接
?? ?2、预定义对象PreparedStatement
?? ?3、设置占位符的？的值
?? ?4、ps.executeUpdate();
BaseDao
package com.DHM.Dao;
import java.lang.reflect.Field;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.List;
import com.DHM.entity.Book;
import com.DHM.util.DBAccess;
import com.DHM.util.PageBean;
/**
* 所有dao层的父类
* @author T440s
*
* @param <T>
*/
public class BaseDao<T> {
/**
* 通用的增删改方法
* @param book
* @throws Exception
*/
public void executeUpdate(String sql,T t,String[] attrs) throws Exception {
// String[] attrs=new String[] {"bid","bname","price"};
Connection con=DBAccess.getConnection();
PreparedStatement ps = con.prepareStatement(sql);
// ps.setObject(1, book.getBid());
// ps.setObject(2, book.getBname());
// ps.setObject(3, book.getPrice());
/**
* 思路：
* 1、从传来的t中读取属性值
* 2、从预定义对象中设置值
*
*/
for (int i=0;i<attrs.length;i++) {
Field f = t.getClass().getDeclaredField(attrs[i]);
f.setAccessible(true);
ps.setObject(i+1, f.get(t));
}
ps.executeUpdate();
}
/**
* 提供解决方案：
* 1、抽取变化部分作为参数：sql、Class（Book.class,article.class）
* 2、抽取公共的父类，把重复的代码剥离出来
*/
private Connection con;
private PreparedStatement ps;
private ResultSet rs;
public List<T> list(String sql,Class<T> clz, PageBean pageBean) throws Exception{
//不确定List集合中装了什么东西 子类Dao继承BaseDao<T>,子类传递什么类.class,那么List集合中放什么。
List<T> list=new ArrayList<T>();
Connection con=DBAccess.getConnection();
PreparedStatement ps=null;
ResultSet rs=null;
// 是否需要分页？
// 无需分页（项目中的下拉框、查询条件教员下拉框，）
// 必须分页（项目中的表类需求、订单列表、学生列表）
if(pageBean !=null && pageBean.isPagination()) {
// 分页（列表需求）
// sql=select * from t_mvc_book where bname like '%圣墟%'
// pagesql=sql limit (page-1)*rows,rows 对应某一页的数据
// countsql=select count(1) from (sql) t 符合条件的总记录数
String countSQL=getCountSQL(sql, pageBean);
ps = con.prepareStatement(countSQL);
rs=ps.executeQuery();
String pagesql=getPageSQL(sql, pageBean);//符合条件的某一数据
ps = con.prepareStatement(pagesql);
rs=ps.executeQuery();
if(rs.next()) {
pageBean.setTotal(String.valueOf(rs.getObject(1)));
}
}else {
// 不分页（select需求）
ps=con.prepareStatement(sql);
rs=ps.executeQuery();
}
while(rs.next()) {
//代码不一样：具体体现在，不同表会有不同字段，那么是体内对应的属性就会不一样;
//list.add(new Book(rs.getInt("bid"), rs.getString("bname"), rs.getFloat("price")));
/**
* 1、实例化一个对象
* 2、从ResultSet对象的属性（bid）获取值，赋值给了前面的实例化的对象
* 3、把已经赋值的对象，添加到List集合中
*/
//实例化
T t=clz.newInstance();
//从ResultSet对象的属性（bid）获取值，赋值给了前面的实例化的对象
Field[] fields = clz.getDeclaredFields();
for (Field f : fields) {
//打开权限
f.setAccessible(true);
f.set(t, rs.getObject(f.getName()));
}
//把已经赋值的对象，添加到List集合中
list.add(t);
}
return list;
}
/**
* 将原生sql转换成符合条件总记录数的countsql
*/
private String getCountSQL(String sql, PageBean pageBean) {
// TODO Auto-generated method stub
return "select count(1) from ("+sql+")";
}
/**
* 将原生sql转换成pagesql
* @param sql
* @param pageBean
* @return
*/
private String getPageSQL(String sql,PageBean pageBean) {
// TODO Auto-generated method stub
return sql+"limit"+pageBean.getPage() +","+pageBean.getRows();
}
}
?BookDao
package com.DHM.Dao;
import java.util.List;
import com.DHM.entity.Book;
import com.DHM.util.PageBean;
import com.DHM.util.StringUtils;
public class BookDao extends BaseDao<Book>{
/*
* 以前的增加方法
public void add(Book book) throws Exception {
String sql="insert into t_mvc_book values(?,?,?)";
Connection con=DBAccess.getConnection();
PreparedStatement ps = con.prepareStatement(sql);
ps.setObject(1, book.getBid());
ps.setObject(2, book.getBname());
ps.setObject(3, book.getPrice());
ps.executeUpdate();
}
增删改查的通用套路
1、建立连接
2、预定义对象PreparedStatement
3、设置占位符的？的值
4、ps.executeUpdate();
*/
public void add(Book book) throws Exception {
String sql="insert into t_mvc_book values(?,?,?)";
super.executeUpdate(sql, book, new String[] {"bid","bname","price"});
}
public void edit(Book book) throws Exception {
String sql="update t_mvc_book set bname=?,price=? where bid=?";
super.executeUpdate(sql, book, new String[] {"bname","price","bid"});
}
public void delete(Book book) throws Exception {
String sql="delete from t_mvc_book where bid=?";
super.executeUpdate(sql, book, new String[] {"bid"});
}
public List<Book> list(Book book,PageBean pagebean) throws Exception {
String sql="select * from t_mvc_book where 1=1";
String bname=book.getBname();
if(StringUtils.isNotBlank(bname)) {
sql+="and bname like '%"+bname+"%'";
}
return super.list(sql, Book.class, pagebean);
}
// public static void main(String[] args) throws Exception {
// Book book=new Book();
// book.setBid(2323);
// book.setBname("小吕秃头");
// book.setPrice(1113);
// BookDao bookdao=new BookDao();
// bookdao.delete(book);
// bookdao.add(book);
// bookdao.edit(book);
// }
}
BookAction
package com.DHM.web;
import java.util.List;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.DHM.Dao.BookDao;
import com.DHM.entity.Book;
import com.DHM.framework.ActionSupport;
import com.DHM.framework.ModelDriver;
import com.DHM.util.PageBean;
/**
* 目标：
* 利用自己做的自定义MVC框架完成增删改查
* 步骤：
* 1、导入框架的Jar包
* 2、做好框架的使用配置
* 3、一切照旧
* JSP、servlet/BookAction 、dao层、entity
* @author T440s
*
*/
public class BookAction extends ActionSupport implements ModelDriver<Book>{
private Book book=new Book();
BookDao bookDao=new BookDao();
@Override
public Book getModel() {
return book;
}
// 增删改最终都要跳回查询页面
// 分析增删改查一共有多少结果集的配置
/**
* 查询：BookList.jsp 返回list
* 增删改确定：book.action?methodName=list 返回：toList
* 增加修改跳转对应页面：bookEdit.jsp 返回：toEdit
* @param req
* @param resp
* @return
*/
public String add(HttpServletRequest req, HttpServletResponse resp) {
try {
bookDao.add(book);
} catch (Exception e) {
e.printStackTrace();
}
return "toList";
}
public String list(HttpServletRequest req, HttpServletResponse resp) {
try {
PageBean pagebean=new PageBean();
bookDao.list(book, pagebean);
List<Book> list=bookDao.list(book, pagebean);
req.setAttribute("books", list);
req.setAttribute("pagebean", pagebean);
} catch (Exception e) {
e.printStackTrace();
}
return "list";
}
public String delete(HttpServletRequest req, HttpServletResponse resp) {
try {
bookDao.delete(book);
} catch (Exception e) {
e.printStackTrace();
}
return "toList";
}
public String edit(HttpServletRequest req, HttpServletResponse resp) {
try {
bookDao.edit(book);
} catch (Exception e) {
e.printStackTrace();
}
return "toList";
}
/**
* 跳转到新增跟修改界面
*/
public String toEdit(HttpServletRequest req, HttpServletResponse resp) {
try {
/**
* 如果是跳转修改界面，那么需要做bid条件的精准查询
*/
if(book.getBid()!=0) {
List<Book> list=bookDao.list(book, null);
req.setAttribute("b", list.get(0));
}
} catch (Exception e) {
e.printStackTrace();
}
return "toEdit";
}
}
?③页面
bookList? 展示界面
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ taglib uri="http://jsp.veryedu.cn" prefix="z"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<!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=UTF-8">
<link
href="https://cdn.bootcdn.net/ajax/libs/twitter-bootstrap/4.5.0/css/bootstrap.css"
rel="stylesheet">
<script
src="https://cdn.bootcdn.net/ajax/libs/twitter-bootstrap/4.5.0/js/bootstrap.js"></script>
<title>书籍列表</title>
<style type="text/css">
.page-item input {
padding: 0;
width: 40px;
height: 100%;
text-align: center;
margin: 0 6px;
}
.page-item input, .page-item b {
line-height: 38px;
float: left;
font-weight: 400;
}
.page-item.go-input {
margin: 0 10px;
}
</style>
</head>
<body>
<form class="form-inline"
action="${pageContext.request.contextPath }/book.action?methodName=list" method="post">
<div class="form-group mb-2">
<input type="text" class="form-control-plaintext" name="bname"
placeholder="请输入书籍名称">
<!-- <input name="rows" value="20" type="hidden"> -->
<!-- 不想分页 -->
<input name="pagination" value="false" type="hidden">
</div>
<button type="submit" class="btn btn-primary mb-2">查询</button>
<a class="btn btn-primary mb-2" href="${pageContext.request.contextPath }/book.action?methodName=toEdit">新增</a>
</form>
<table class="table table-striped bg-success">
<thead>
<tr>
<th scope="col">书籍ID</th>
<th scope="col">书籍名</th>
<th scope="col">价格</th>
<th scope="col">操作</th>
</tr>
</thead>
<tbody>
<c:forEach var="b" items="${books }">
<tr>
<td>${b.bid }</td>
<td>${b.bname }</td>
<td>${b.price }</td>
<td>
<a href="${pageContext.request.contextPath }/book.action?methodName=toEdit&bid=${b.bid}">修改</a>
<a href="${pageContext.request.contextPath }/book.action?methodName=delete&bid=${b.bid}">删除</a>
</td>
</tr>
</c:forEach>
</tbody>
</table>
<!-- 这一行代码就相当于前面分页需求前端的几十行了 -->
<z:page pageBean="${pageBean }"></z:page>
</body>
</html>bookEdit? 增加修改界面
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ taglib uri="http://jsp.veryedu.cn" prefix="z"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<link
href="https://cdn.bootcdn.net/ajax/libs/twitter-bootstrap/4.5.0/css/bootstrap.css"
rel="stylesheet">
<script
src="https://cdn.bootcdn.net/ajax/libs/twitter-bootstrap/4.5.0/js/bootstrap.js"></script>
<title>书籍新增/修改</title>
</head>
<body>
<form class="form-inline"
action="${pageContext.request.contextPath }/book.action?methodName=${empty b ? 'add' : 'edit'}" method="post">
书籍ID：<input type="text" name="bid" value="${b.bid }"><br>
书籍名称：<input type="text" name="bname" value="${b.bname }"><br>
书籍价格：<input type="text" name="price" value="${b.price }"><br>
<input type="submit">
</form>
</body>
</html>判断是修改还是增加?
<form class="form-inline"
?? ??? ?action="${pageContext.request.contextPath }/book.action?methodName=${empty b ? 'add' : 'edit'}" method="post">
?? ??? ?书籍ID：<input type="text" name="bid" value="${b.bid }"><br>
?? ??? ?书籍名称：<input type="text" name="bname" value="${b.bname }"><br>
?? ??? ?书籍价格：<input type="text" name="price" value="${b.price }"><br>
?? ??? ?<input type="submit">
?? ?</form>
⑤展示效果
修改
?增加
?展示界面效果
没有啦！！！