[开发测试]自定义MVC框架（加强）

思维导图~~??

?

一、mvc框架

1、导入jar包

①、将自定义mvc框架? 自定义MVC框架_小丸子?的博客-CSDN博客? ?中（com.mwy.framework、com.mwy.util、com.mwy.tag打包成一个 jar包，右键Export ->JAR file->一直下一步就可）名称为 mvc.jar?（com.mwy.util中修改BaseDao中增加通用增删改方法）

package com.mwy.util;
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.mwy.entity.Book;
/**
 * 所有到层的父类
 */
public class BaseDao<T> {
	/**
	 * 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;
	/**
	 * 通用的增删改方法
	 * @param book
	 * @throws Exception
	 */
	public void executeUpdate(String sql,T t,String[] attrs) throws Exception {
	con=DBAccess.getConnection();
	ps=con.prepareStatement(sql);
//	ps.setObject(1, book.getBid());
//	ps.setObject(2, book.getBname());
//	ps.setObject(3, book.getPrice());
	/**
	 * 思路：
	 * 1、从传进来的t中读取属性值
	 * 2、王预编译对象中设置了值
	 */
	for (int i = 0; i < attrs.length; i++) {
		Field f = t.getClass().getDeclaredField(attrs[i]);
		f.setAccessible(true);
		f.get(t);
		ps.setObject(i+1, f.get(t));
	}
	ps.executeUpdate();
}

	/**
	 * 通用分页查询
	 * @param sql
	 * @param clz
	 * @return
	 * @throws Exception
	 */
	public List<T> executeQuery(String sql,Class<T> clz,PageBean pageBean) throws Exception{
		List<T> list=new ArrayList<T>();
		con=DBAccess.getConnection();
		ps=null;
		rs=null;
		/**
		 * 是否分页？
		 * 无需分页（项目中的下拉框，查询条件教员下拉框无需分页）
		 * 必须分页（项目中列表类需求，）
		 */
		if(pageBean!=null&&pageBean.isPagination()) {
			String countSql=getCountSql(sql);
			ps=con.prepareStatement(countSql);//符合条件的某一页数据
			rs=ps.executeQuery();
			if(rs.next()) {				
				pageBean.setTotal(String.valueOf(rs.getObject(1)));
			}
			//挪到下面，是因为最后才处理结果集
			//必须分页
//		原生sql=select * from t_mvc_book where bname like '%圣墟%'
//		pageSql=sql limit (n-1)*rows,rows 
//		countSql=select count(1) from (sql) t 符合条件的总记录数
			String pageSql=getPageSql(sql,pageBean);
			ps=con.prepareStatement(pageSql);//符合条件的某一页数据
			rs=ps.executeQuery();
			
		}else {
			//不分页
			ps=con.prepareStatement(sql);//符合条件的所有数据
			rs=ps.executeQuery();	
		}
		while(rs.next()) {
			T t=clz.newInstance();
			Field[] fields = clz.getDeclaredFields();
			for (Field f : fields) {
				f.setAccessible(true);
				f.set(t, rs.getObject(f.getName()));
			}
			list.add(t);
		}
		return list;
	}
	/**
	 * 将原生sql转换成countSql
	 * @param sql
	 * @return
	 */
	private String getCountSql(String sql) {
		// countSql=select count(1) from (sql) t 符合条件的总记录数
		return "select count(1) from ("+sql+") t";
	}
/**
 * 将原生sql转换成pageSql
 * @param sql
 * @param pageBean
 * @return
 */
	private String getPageSql(String sql,PageBean pageBean) {
		//pageSql=sql limit (n-1)*rows,rows 
		return sql+" limit "+pageBean.getStartIndex()+","+pageBean.getRows();
	}	

}

②、导入自定义MVC框架所使用的相关jar包

?2、web.xml做配置

①、WEB-INF 下的 web.xml

<?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>Mvc_crud</display-name>
  <servlet>  
     <servlet-name>mvc</servlet-name>
     <servlet-class>com.mwy.framework.DispatchServlet</servlet-class>
     <init-param>
        <param-name>configurationLocation</param-name>
        <param-value>/mvc.xml</param-value>
     </init-param>
  </servlet>
  <servlet-mapping>
     <servlet-name>mvc</servlet-name>
     <url-pattern>*.action</url-pattern>
  </servlet-mapping>
</web-app>

②、JAVA Resources 下的 conf->mvc.xml (自己建的)

<?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
	 -->
	<action path="/book" type="com.mwy.web.BookAction">
<!-- 	 查询：BookList.jsp		返回值：list -->
<!-- 	 增删改确定：book.action?methodName=list	返回值：toList -->
<!-- 	 增加修改跳转对应界面：bookEdit.jsp	返回值：toEdit -->
		<forward name="list" path="/bookList.jsp" redirect="false" />
		<forward name="toList" path="/book.action?methodName=list" redirect="true" />
		<forward name="toEdit" path="/bookEdit.jsp" redirect="false" />
	</action>
</config>

二、正式开发

1、实体类

package com.mwy.entity;
public class Book {
	private int bid;
	private String bname;
	private float price;
	public int getBid() {
		return bid;
	}
	public void setBid(int bid) {
		this.bid = bid;
	}
	public String getBname() {
		return bname;
	}
	public void setBname(String bname) {
		this.bname = bname;
	}
	public float getPrice() {
		return price;
	}
	public void setPrice(float price) {
		this.price = price;
	}
	@Override
	public String toString() {
		return "Book [bid=" + bid + ", bname=" + bname + ", price=" + price + "]";
	}
}

2、dao方法

package com.mwy.dao;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import com.mwy.entity.Book;
import com.mwy.util.BaseDao;
import com.mwy.util.DBAccess;
import com.mwy.util.PageBean;
import com.mwy.util.StringUtils;
import com.sun.xml.internal.bind.v2.schemagen.xmlschema.List;
import sun.security.pkcs11.Secmod.DbMode;
public class BookDao extends BaseDao<Book>{
	
	/*最初写方法
        private void add(Book book) throws Exception {
		String sql="insert into t_mvc_book value(?,?,?)";
		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、预编译对象PreparedStatement
	3、设置占位符？的值
	4、ps.executeUpdate();
	*/
	//增加
	public void add(Book book) throws Exception {
		String sql="insert into t_mvc_book value(?,?,?)";
		super.executeUpdate(sql, book, new String[] {"bid","bname","price"});
	}
	//删除
	public void del(Book book) throws Exception {
		String sql="delete from t_mvc_book where bid=?";
		super.executeUpdate(sql, book, new String[] {"bid"});
	}				
	//修改
	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"});
	}		
	//查询
	public java.util.List<Book> list(Book book,PageBean pageBean) throws Exception {
		String sql="select * from t_mvc_book where 1=1";
		String bname=book.getBname();
		int bid=book.getBid();
		if(StringUtils.isNotBlank(bname)) {
			sql+=" and bname like '%"+bname+"%'";
		}
		if(bid!=0) {
			sql+=" and bid="+bid;
		}
		return super.executeQuery(sql, Book.class, pageBean);
	}	
}

3、子控制器（继承ActionSupport实现ModelDriver<T>）

package com.mwy.web;
import java.util.List;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.mwy.dao.BookDao;
import com.mwy.entity.Book;
import com.mwy.framework.ActionSupport;
import com.mwy.framework.ModelDriver;
import com.mwy.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
 */
public class BookAction extends ActionSupport implements ModelDriver<Book>{
	private Book book=new Book();
	private BookDao bookDao=new BookDao();
	
	/**
	 * 增删改最终都需要调回查询界面
	 * 分析增删改查一共有多少结果集的配置
	 * 查询：BookList.jsp  返回值;list
	 * 增删改：book.action?methodName=list  返回值：toList
	 * 增加修改跳转对应界面;bookEdit.jsp   返回值：toEdit
	 * @throws Exception 
	 */
	//增
	public String add(HttpServletRequest req, HttpServletResponse resp) throws Exception {
		bookDao.add(book);
		return "toList";
	}
	//删
	public String del(HttpServletRequest req, HttpServletResponse resp) throws Exception {
		bookDao.del(book);
		return "toList";
	}		
	//改
	public String edit(HttpServletRequest req, HttpServletResponse resp) throws Exception {
		bookDao.edit(book);
		return "toList";
	}	
	/**
	 * 跳转到新增修改界面
	 */
	public String toEdit(HttpServletRequest req, HttpServletResponse resp) throws Exception {
		/**
		 * 如果是跳转页面，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));
		}
		return "toEdit";
	}			
	
	//查询界面
	public String list(HttpServletRequest req, HttpServletResponse resp)  throws Exception {
			PageBean pageBean = new PageBean();
			pageBean.setRequest(req);
			List<Book> list = bookDao.list(book,pageBean);
			req.setAttribute("books", list);
			req.setAttribute("pageBean", pageBean);
		return "list";
	}
	
	@Override
	public Book getModel() {
		// TODO Auto-generated method stub
		return book;
	}
}

4、页面

①、展示页面

<%@ page language="java" contentType="text/html; charset=UTF-8"
	pageEncoding="UTF-8"%>
<%@taglib uri="http://java.veryedu.cn" prefix="zking" %>
<%@ 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="${pageContext.request.contextPath }/book.action?methodName=del&bid=${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 -->
		<zking:Page pageBean="${pageBean }"></zking:Page>
</body>
</html>

②增加修改页面

<%@ page language="java" contentType="text/html; charset=UTF-8"
	pageEncoding="UTF-8"%>
<%@taglib prefix="zking" uri="http://java.veryedu.cn"%>	
<%@ 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 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>

5、结果界面展示

到这里就结束了~~~