mvc知识总结

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阳某 2021-09-02 11:12:00 ©著作权

文章标签 自定义mvc sql java html mvc 文章分类 代码人生

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文章目录

mvc增删改查
导出jar包

mvc增删改查

原理：利用我们上次写好的自定义框架，把它打成jar包导入，进行对书本的增删查改的操作。利用转发和重定向在控制器内部跳转避免重复提交数据。

BaseDao

package com.xy.util;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.List;


public class BaseDao<T> {
	
	public static interface CallBack<E>{
		//遍历ResultSet结果集
		public List<E> forEach(ResultSet rs) throws SQLException;
	}

	/**
	 * 分页查询
	 * @param sql 普通的sql
	 * @param pageBean 
	 * @return
	 */
	public List<T> executeQuery(String sql,PageBean pageBean,CallBack<T> callBack){
	
		Connection conn=null;
		PreparedStatement stmt=null;
		ResultSet rs=null;
		try {
			conn=DBHelper.getConnection();
			//判断是否分页
			if(null!=pageBean&&pageBean.isPagination()) {
				//第一次查询总记录数
				String countSql=this.getCountSql(sql);
				stmt=conn.prepareStatement(countSql);
				rs=stmt.executeQuery();
				if(rs.next()) {
					Object obj = rs.getObject(1);
					pageBean.setTotal(Integer.parseInt(obj.toString()));
				}
				//DBHelper.close(conn, stmt, rs);
				//第二次满足条件的分页数据集
				sql=this.getPagerSql(sql, pageBean);
			}
			stmt=conn.prepareStatement(sql);
			rs=stmt.executeQuery();
			//处理结果集
			return callBack.forEach(rs);
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			DBHelper.close(conn, stmt, rs);
		}
		return null;
	}
	
	/**
	 * 将普通的Sql语句转换成查总记录数的Sql语句
	 * 例如：sql=="select * from t_book where bookname='123'"
	 * @param sql
	 * @return
	 */
	private String getCountSql(String sql) {
		return "select count(1) from ("+sql+") t1";
	}
	
	/**
	 * 将普通Sql语句转换成查询分页的Sql语句
	 * 例如：sql=="select * from t_book where bookname='123'"
	 * @param sql
	 * @param pageBean
	 * @return
	 */
	private String getPagerSql(String sql,PageBean pageBean) {
		return sql+" Limit "+pageBean.getStartIndex()+","+
					pageBean.getRows();
	}
}

BookAction

package com.xy.web;

import java.io.IOException;
import java.sql.SQLException;
import java.util.List;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.sql.rowset.serial.SerialException;

import com.util.PageBean;
import com.xy.dao.BookDao;
import com.xy.entity.Book;
import com.xy.framework.DispatcherServlet;
import com.xy.framework.ModelDriver;

public class BookAction extends DispatcherServlet implements ModelDriver<Book> {
	
	private Book book=new Book();
	
	private BookDao bookDao=new BookDao();
	
	
	@Override
	public Book getModel() {
		return book;
	}
	
	/**
	 * 书本新增
	 * @param req
	 * @param resp
	 * @return
	 * @throws SerialException
	 * @throws IOException
	 */
	public String addBook(HttpServletRequest req,HttpServletResponse resp)throws SerialException,IOException {
		bookDao.addBook(book);
//		bookAction.action?menthodName=queryBookPager
		req.getSession().setAttribute("message", "新增书本信息成功");
		return "success";
	}
	
	/**
	 * 删除
	 * @param req
	 * @param resp
	 * @return
	 * @throws SerialException
	 * @throws IOException
	 */
	public String delBook(HttpServletRequest req,HttpServletResponse resp)throws SerialException,IOException {
		bookDao.delBook(book);
		req.getSession().setAttribute("message", "删除书本信息成功");
		return "success";
	}
	/**
	 * 修改
	 * @param req
	 * @param resp
	 * @return
	 * @throws SerialException
	 * @throws IOException
	 */
	public String editBook(HttpServletRequest req,HttpServletResponse resp)throws SerialException,IOException {
		bookDao.editBook(book);
		req.getSession().setAttribute("message", "修改书本信息成功");
		return "success";
	}
	
	/**
	 * 查所有
	 * @param req
	 * @param resp
	 * @return
	 * @throws SerialException
	 * @throws IOException
	 */
	public String queryBookPager(HttpServletRequest req,HttpServletResponse resp)throws SerialException,IOException {
		PageBean pageBean=new PageBean();
		pageBean.setRequest(req);
		
			List<Book> books = bookDao.queryBookPager(book, pageBean);
			req.setAttribute("books", books);
			req.setAttribute("pageBean", pageBean);
		return "success";
	}
	
	/**
	 * 查单个
	 * @param req
	 * @param resp
	 * @return
	 * @throws SerialException
	 * @throws IOException
	 */
	public String querySingleBook(HttpServletRequest req,HttpServletResponse resp)throws SerialException,IOException {
		Book b=bookDao.querySingleBook(book);
		req.setAttribute("book", b);
		
		//定义类型参数，告知去哪里，修改页面，详情页面
		String type=req.getParameter("type");
		if("edit".equals(type)) {
			return "edit";
		}
		else {
			return "detail";
		}
	}
}

Book

package com.xy.entity;

public class Book {
	private int bid;
	private String bname;
	private float price;

	@Override
	public String toString() {
		return "Book [bid=" + bid + ", bname=" + bname + ", price=" + 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;
	}

	public Book(int bid, String bname, float price) {
		super();
		this.bid = bid;
		this.bname = bname;
		this.price = price;
	}

	public Book() {
		super();
	}
}

BookDao

package com.xy.dao;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.List;

import com.util.BaseDao;
import com.util.PageBean;
import com.util.StringUtils;
import com.xy.entity.Book;
import com.xy.util.BaseDao.CallBack;
import com.xy.util.CommonUtils;
import com.xy.util.DBHelper;

public class BookDao extends BaseDao<Book>{
	
	public void addBook(Book book) {
		String sql="insert into t_mvc_book";
		Connection con=null;
		PreparedStatement ps=null;
		try {
			con=DBHelper.getConnection();
			ps=con.prepareStatement(sql);
			ps.setInt(1, book.getBid());
			ps.setString(2, book.getBname());
			ps.setFloat(3, book.getPrice());
			ps.executeQuery();
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			DBHelper.close(con, ps, null);
		}
	}
	
	public void editBook(Book book) {
		String sql="update tb_t_mvc_book set bname=?,price=? where bid=?";
		Connection con=null;
		PreparedStatement ps=null;
		try {
			con=DBHelper.getConnection();
			ps=con.prepareStatement(sql);
			ps.setString(1, book.getBname());
			ps.setFloat(2, book.getPrice());
			ps.setInt(3, book.getBid());
			ps.executeQuery();
		} catch (Exception e) {
			e.printStackTrace();
		}finally {
			DBHelper.close(con, ps, null);
		}
	}
	
	public void delBook(Book book) {
		String sql="delete from t_mvc_book where bid=?";
		Connection con=null;
		PreparedStatement ps=null;
		try {
			con=DBHelper.getConnection();
			ps=con.prepareStatement(sql);
			ps.setInt(1, book.getBid());
			ps.executeQuery();
		} catch (Exception e) {
			e.printStackTrace();
		}finally {
			DBHelper.close(con, ps, null);
		}
	}
	
	/**
	 * 查所有
	 * @param book
	 */
	public List<Book> queryBookPager(Book book,PageBean pageBean) throws InstantiationException, IllegalAccessException, IllegalArgumentException, SQLException {
		String sql="select * from t_mvc_book where 1=1 ";		
		if(StringUtils.isBlank(book.getBname())) {
			sql+=" and bname like '%"+book.getBname()+"%'";
		}
		sql+=" order by bid desc";
			return super.executeQuery(sql, pageBean,new CallBack<Book>() {

				@Override
				public List<Book> forEach(ResultSet rs) {
						return CommonUtils.toList(rs,Book.class);
				}
			});
	}
	
	@Override
	public Book querySingleBook(Book book) {
		String sql="select * from t_mvc_book where bid=?";
		List<Book> list = super.executeQuery(sql, null, new CallBack<Book>() {

			@Override
			public List<Book> forEach(ResultSet rs) throws SQLException, Exception {
				return CommonUtils.toList(rs, Book.class);
			}
		});
		if(null!=list||0!=list.size()) {
			return list.get(0);
		}
		else {
			return null;
		}
	}
}

config.xml配置文件

<?xml version="1.0" encoding="UTF-8"?>
<config>
	<action path="/bookAction" type="com.xy.web.BookAction">
		 <forward name="success" path="/bookAction?methodName=queryBookPager" redirect="true" />
		  <forward name="list" path="/bookList.jsp" redirect="false" />  
		  <forward name="edit" path="bookEdit.jsp"></forward>
		  <forward name="detail" path="bookDetail.jsp"></forward>
	</action>
</config>

bookList.jsp（主页面）

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
    <%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
    <%@ include file="showMessage.jsp" %>
<!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">
<title>主页面</title>
</head>
<body>

<form action="${pageContext.request.contextPath}/bookAction.action?MethodName=list" method="post">
	书本名称：<input type="text" name="bname" />
	<input type="submit" value="查询" /><a href="bookAdd.jsp">新增书本信息</a>
	<input type="hidden" name="methodName" value="queryBookPager" />
</form>

<table border="1px">
	<th>书本编号</th>
	<th>书本名称</th>
	<th>书本价格</th>
	<tbody>
		<c:forEach items="${books}" var="book">
		<tr>
			<td>${book.bid}</td>
			<td>${book.bname}</td>
			<td>${book.price}</td>
			<td>
				<a href="bookAction.action?methodName=delBook&&bid=${book.bid }">删除</a>
				<a href="bookAction.action?methodName=querySingleBook&type=edit&bid=${book.bid }">修改</a>
				<a href="bookAction.action?methodName=querySingleBook&type=detail&bid=${book.bid }">详情</a>
			</td>
		</tr>
		</c:forEach>
	</tbody>
</table>

</body>
</html>

bookAdd.jsp（增加）

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!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">
<title>Insert title here</title>
</head>
<body>
<h1>新增书本</h1>
<form action="bookAction.action" method="post">
	<input type="hidden" name="bid" />
	书本名称：<input type="text" name="bname" /><br/>
	书本价格：<input type="text" name="price" /><br/>
	
	<input type="submit" value="增加"  />
	<input type="hidden" name="methodName" value="addBook" //>
</form>
</body>
</html>

bookEdit.jsp（修改）

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!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">
<title>Insert title here</title>
</head>
<body>
<h1>修改书本信息</h1>
<form action="bookAction.action" method="post">
	<input type="hidden" name="bid" value="${book.bid }" />
	书本名称：<input type="text" name="bname" value="${book.bname }" /><br/>
	书本价格：<input type="text" name="price" value="${book.price }" /><br/>
	
	<input type="submit" value="修改"  />
	<input type="hidden" name="methodName" value="editBook" //>
</form>
</body>
</html>

showMessage.jsp（封装的消息提示页面）

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<scrip>
var msg='${message}';
if(msg){
	window.onload=function(){
		alert(msg);
	};
}
</scrip>
<c:remove var="message" scope="session"/>

导出jar包

把自己项目打成Jar包步骤：
mvc知识总结_java
选择jar文件
mvc知识总结_mvc_02
我们只需要框架就好了,取消classpath和project
mvc知识总结_sql_03