一、搭建环境

1、在之前的MVC（2）里把

Action.java
ActionModel.java
ActionSupport.java
ConfigModel.java
ConfigModelFactory.java
DispatcherServlet.java
ForwardModel.java
ModelDriven.java

这几个类导成mvc.jar包，在使用的把此mvc.jar包之前jar包导进去

2、把通用分页的助手类也拿过来

3、共用类（在之前的basedao里添加）

	//将以下代码不一样的提出来作为参数放到方法里，以及对象不能是定死的，所以将它换为泛型
	public int executeUpdate(String sql,T t,String [] attrs) throws Exception {
		Connection con = DBAccess.getConnection();
		PreparedStatement ps = con.prepareStatement(sql);
		//将 t 的某一个属性对应的值加到ps对象中
		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));
		}
		return ps.executeUpdate();
	}

	
}

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二、增加

方法层：

	//增加
	public int add(Book b) throws Exception {
		String sql = "insert into tb_book values(?,?)";
		return super.executeUpdate(sql, b, new String[] {"bid","bname"});
	}
	
}

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servlect层：（在之前的BookAction里写以下代码）

//增加
	public String add(HttpServletRequest req, HttpServletResponse resp) {
		try {
			bookDao.add(book);
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		//表示跳到查询界面
		return "toList";
	}
	
	
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三、删除

方法层：

//删除
	public int del(Book b) throws Exception {
		String sql = "delete from tb_book where bid=?";
		return super.executeUpdate(sql, b, new String[] {"bid"});
	}
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servlect层：

//删除
	public String del(HttpServletRequest req, HttpServletResponse resp) {
		try {
			bookDao.del(book);
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		//表示跳到查询界面
		return "toList";
	}
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四、修改

方法层：

	
	//修改
	public int update(Book b) throws Exception {
		String sql = "update tb_book set bname=? where bid=?";
		return super.executeUpdate(sql, b, new String[] {"bname","bid"});
	}
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servlet层：

//查询
	public String list(HttpServletRequest req, HttpServletResponse resp) {
		try {
			PageBean pageBean = new PageBean();
			//初始化
			pageBean.setReq(req);
			List<Book> list = bookDao.list(book,pageBean);
			req.setAttribute("books", list);
			req.setAttribute("pb", pageBean);
		} catch (Exception e) {
			e.printStackTrace();
		}
		//执行查询
		return "list";
	}
	

	//跳转到新增或修改界面
	public String preEdit(HttpServletRequest req, HttpServletResponse resp) {
		try {
			int bid = book.getBid();
			if(bid != 0) {
				//传递bid到后台，且只能查出一条数据，那么list集合里只有一条数据
				List<Book> list = bookDao.list(book,null);
				//id对应的值list.get(0)
				req.setAttribute("book", list.get(0));
			}
		} catch (Exception e) {
			e.printStackTrace();
		}
		//表示跳到查询界面
		return "toEdit";
	}
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五、查询

方法层：

//查询
	public List<Book> list(Book book,PageBean pageBean) throws Exception{
	 String sql = "select * from tb_book where 1=1 ";
	 String bname = book.getBname();
	 System.out.println(book.getBname());
	 if(StringUtils.isNotBlank(bname)) {
		 sql += " and bname like '%"+bname+"%'";
	 }
	 int bid = book.getBid();
	 //前台传递到后台，只要传了就有值,没传就是默认值，默认值为0
	 if(bid!=0) {
		 sql += " and bid = "+bid;
	 }
		return super.list(sql, pageBean, rs ->{
			List<Book> ls = new ArrayList<Book>();
			try {
				while(rs.next()) {
					ls.add(new Book(rs.getInt("bid"), rs.getString("bname")));
				}
			} catch (Exception e) {
				e.printStackTrace();
			}
			return ls;
		});
	}
	
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servlet层：

//查询
	public String list(HttpServletRequest req, HttpServletResponse resp) {
		try {
			PageBean pageBean = new PageBean();
			//初始化
			pageBean.setReq(req);
			List<Book> list = bookDao.list(book,pageBean);
			req.setAttribute("books", list);
			req.setAttribute("pb", pageBean);
		} catch (Exception e) {
			e.printStackTrace();
		}
		//执行查询
		return "list";
	}
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六、使用

<%@ 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="${pageContext.request.contextPath }/book.action?methodName=list" method="post">
		<div class="form-group mb-2">
			<input type="text" class="form-control-plaintext" name="bname"
				placeholder="请输入书籍名称">
		</div>
		<button type="submit" class="btn btn-primary mb-2">查询</button>
		<a  type="submit" class="btn btn-primary mb-2" 
		href="${pageContext.request.contextPath }/book.action?methodName=preEdit">增加</a>
	</form>

	<table class="table table-striped ">
		<thead>
			<tr>
				<th scope="col">书籍ID</th>
				<th scope="col">书籍名</th>
				<th>操作</th>
			</tr>
		</thead>
		<tbody>
		<c:forEach items="${books }" var="b">
			<tr>
				<td>${b.bid }</td>
				<td>${b.bname }</td>
				<td>
				 <a href="${pageContext.request.contextPath }/book.action?methodName=preEdit&bid=${b.bid}" >编辑</a>
				 <a href="${pageContext.request.contextPath }/book.action?methodName=del&bid=${b.bid}" >删除</a>
					
				</td>
			</tr>
		</c:forEach>

		</tbody>
	</table>

<z:page pagebean="${pb }"></z:page>
</body>
</html>
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界面展示：