自定义MVC03 增删改查

一、环境搭建

1.将框架打成jar包，然后导入新工程，并且把框架的依赖jar包导入进去

2.将分页标签相关文件、及相关助手类导入

3.框架的配置文件添加、以及web.xml的配置-以后开源框架的使用从这一步开始

二、增删改查

一、环境搭建

1.将框架打成jar包，然后导入新工程，并且把框架的依赖jar包导入进去
在之前的MVC集合框架里把

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.将分页标签相关文件、及相关助手类导入

3.框架的配置文件添加、以及web.xml的配置-以后开源框架的使用从这一步开始

web.xml



  y1_mvc_crud
   
  	mvc
  	com.maomao.framework.DisPatcherServlet
  	
  		configLocation
  		/aa.xml
  	
  
  
  	mvc
  	*.action

aa.tld




    
  JSTL 1.1 core library
  JSTL core
  1.1
  z
  http://jsp.veryedu.cn

  
    
        Provides core validation features for JSTL tags.
    
    
        org.apache.taglibs.standard.tlv.JstlCoreTLV
    
  

  
  
    page
    com.maomao.tag.PageTag
    JSP
    
        pageBean
        true
        true

二、增删改查

环境搭建好之后就可以开始编码了

Book实体类

package com.maomao.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;
	}
	
	public Book() {
		// TODO Auto-generated constructor stub
	}
	public Book(int bid, String bname, float price) {
		super();
		this.bid = bid;
		this.bname = bname;
		this.price = price;
	}
	@Override
	public String toString() {
		return "Book [bid=" + bid + ", bname=" + bname + ", price=" + price + "]";
	}
	
	
	

}

BaseDao.java

package com.maomao.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.maomao.entity.Book;


public class BaseDao {

	
	
	public List executeQuery(String sql,PageBean pageBean,CallBack callBack) throws Exception{
//		SELECt * FROM 'tb_book' WHERe bname like '%哈哈哈%';
		//从上面得到SELECt COUNT(1) as n FROM (SELECt * FROM tb_book WHERe bname LIKE '%哈哈哈%') t;
		//目的是为了得到总记录数---->总目的是得到总页数
		
		Connection con = null;//重复代码1
		PreparedStatement ps = null;//重复代码2
		ResultSet rs = null;//重复代码3
		if(pageBean !=null && pageBean.isPagination()) {
			String countSql = getCountSql(sql);
			 con = DBAccess.getConnection();//重复代码1
			 ps = con.prepareStatement(countSql);//重复代码2
			 rs = ps.executeQuery();//重复代码3
			 System.out.println(countSql);
			 if(rs.next()) {
				 //因为下面Sql语句里有个n 将n放进以下代码
				 //pageBean（当前实体类）就包含了总记录数
				 pageBean.setTotal(rs.getString("n"));
			 }
			 String pageSql = getpageSql(sql,pageBean);
			 con = DBAccess.getConnection();//重复代码1
			 ps = con.prepareStatement(pageSql);//重复代码2
			 rs = ps.executeQuery();//重复代码3
		}
		else {
			 con = DBAccess.getConnection();//重复代码1
			 ps = con.prepareStatement(sql);//重复代码2
			 rs = ps.executeQuery();//重复代码3
		}
		return callBack.foreach(rs);
	}

	
	
	private String getpageSql(String sql,PageBean pageBean) {
		// TODO Auto-generated method stub
		return sql + " limit "+pageBean.getStartIndex() + ","+pageBean.getRows();
	}

	
	private String getCountSql(String sql) {
		// TODO Auto-generated method stub
		return "select count(*) as n from ("+sql+") t";
	}
	
	//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();
	}
	
	
}

BookDao.java

package com.maomao.dao;

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

import com.maomao.entity.Book;
import com.maomao.util.BaseDao;
import com.maomao.util.DBAccess;
import com.maomao.util.PageBean;
import com.maomao.util.StringUtils;

public class BookDao extends BaseDao{

//	查询
	public List list(Book b,PageBean pageBean) throws Exception{
		String sql="select * from tb_book where 1=1";
		String bname=b.getBname();
		if(StringUtils.isNotBlank(bname)) {
			sql+=" and bname like '%"+bname+"%'";
		}
		int bid=b.getBid();
//		前台jsp传递到后台，只要传了就有值，没传就是默认值，默认值就是0
		if(bid!=0) {
			sql+=" and bid="+bid;
		}
		return super.executeQuery(sql, pageBean, rs ->{
			List list=new ArrayList<>();
			try {
				while(rs.next()) {
					list.add(new Book(rs.getInt("bid"), rs.getString("bname"), rs.getFloat("price")));
				}
			} catch (Exception e) {
				e.printStackTrace();
			}
			return list;
		});
	}
	
//	增
	
	public int add(Book b) throws Exception {
		Connection con = DBAccess.getConnection();
		String sql="insert into tb_book value(?,?,?)";
		return super.executeUpdate(sql, b, new String[] {"bid","bname","price"});
	}
	
//	删
	
	public int del(Book b) throws Exception {
		Connection con = DBAccess.getConnection();
		String sql="delete from tb_book where bid=?";
		return super.executeUpdate(sql, b, new String[] {"bid"});
	}
	
//	改
	
	public int edit(Book b) throws Exception {
		Connection con = DBAccess.getConnection();
		String sql="update tb_book set bname=?,price=? where bid=?";
		return super.executeUpdate(sql, b, new String[] {"bname","price","bid"});
	}
	

}

BookAction.java

package com.maomao.web;

import java.util.List;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.maomao.dao.BookDao;
import com.maomao.entity.Book;
import com.maomao.framework.ActionSupport;
import com.maomao.framework.ModelDriven;
import com.maomao.util.PageBean;

public class BookAction extends ActionSupport implements ModelDriven{

	private Book b=new Book();
	private BookDao bd =new BookDao();
	
	@Override
	public Book getModel() {
		return b;
	}
	
//	增
	public String add(HttpServletRequest req, HttpServletResponse resp) {
		try {
			bd.add(b);
		} catch (Exception e) {
			e.printStackTrace();
		}
//		代表跳到查询界面
		return "toList";
	}

//	删
	public String del(HttpServletRequest req, HttpServletResponse resp) {
		try {
			bd.del(b);
		} catch (Exception e) {
			e.printStackTrace();
		}
//		代表跳到查询界面
		return "toList";
	}
	
//	修
	public String edit(HttpServletRequest req, HttpServletResponse resp) {
		try {
			bd.edit(b);
		} catch (Exception e) {
			e.printStackTrace();
		}
//		代表跳到查询界面
		return "toList";
	}
	
//	查询
	public String list(HttpServletRequest req, HttpServletResponse resp) {
		try {
			PageBean pageBean=new PageBean();
			pageBean.setRequest(req);
			List list = bd.list(b, pageBean);
			req.setAttribute("list", list);
			req.setAttribute("pageBean", pageBean);
		} catch (Exception e) {
			e.printStackTrace();
		}
//		执行查询展示
		return "list";
	}
	
//	跳转到新增/修改界面
		public String preEdit(HttpServletRequest req, HttpServletResponse resp) {
			try {
				int bid = b.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 list = bd.list(b,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";
	}
	
}

前台代码 booklist.jsp

<%@ 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"%>






书籍列表



	
		
			
		
		
		增加
	

	
			
		
			
				书籍ID
				书籍名
				操作
			
		
		
		
				${b.bid }
				${b.bname }
				
				 编辑
				 删除

自定义MVC03 增删改查

2.将分页标签相关文件、及相关助手类导入

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