[大数据]自定义mvc框架的应用

前言：前面俩次跟大家分享了mvc框架的编写，今天用框架来实现增删查改的功能

思维导图

?

一、对相关配置文件的优化

步骤：在java Resources新建一个source folder文件夹（注意该文件夹与原有的src文件夹同级）把我们导出的.jar文件放进去

配置好我们的.xml文件 代码如下（跟我们前面的config.xml内容是一样的）

<?xml version="1.0" encoding="UTF-8"?>
<config>
	<action path="/book" type="com.zking.web.StudentAction">
		<forward name="list" path="/index.jsp" redirect="false" />
<!-- 		增删改操作之后要再一次查询数据库的新的数据做展示 -->
		<forward name="toList" path="/book.action?methodName=list" redirect="true" />
		<forward name="toEdit" path="/bookEdit.jsp" redirect="false" />
	</action>
	
</config>

在中央控制器要进行判断

public void init() throws ServletException {
		try {
			//configModel = ConfigModelFactory.build();
			//配置的文件位置：web.xml
			String configurationLocation = this.getInitParameter("configurationLocation");
			if(configurationLocation==null ||"".equals(configurationLocation)) {
				configurationLocation="/zking.xml";
			}
			configModel = ConfigModelFactory.build(configurationLocation);
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}

运行结果

二，通用的增删查改1

1.建立一个dao包里面编写一个基础dao类（里面写所有的通用方法）代码如下所示

package com.dff.util;

import java.lang.reflect.Field;
import java.sql.Connection;

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

import com.dff.util.DBAccess;
import com.dff.util.PageBean;

public class BaseDao<T> {
	public interface CallBack<T>{
		public List<T> forEach(ResultSet rs) throws Exception;
	}
	
	/**
	 * 通用的增删改
	 * @param sql 具体的增删改sql
	 * @param t 具体要操作的表对应的实体类
	 * @param attrs 具体操作的表的某些字段对应的实体类属性
	 * @throws Exception 
	 */
	public void executeUpdate(String sql,T t,String[] attrs) throws Exception {
		//把参数传进来
		Connection con = DBAccess.getConnection();
		PreparedStatement pst = con.prepareStatement(sql);
		for (int i = 0; i < attrs.length; i++) {
			Field f = t.getClass().getDeclaredField(attrs[i]);
			f.setAccessible(true);
			pst.setObject(i+1, f.get(t));
		}
		pst.executeUpdate();
	}
	
	/**
	 * 1.通用分页两个基本要素
	 *   1.1 需要知道满足条件的条目数
	 *   1.2查询满足条件指定页码的结果
	 * @throws Exception 
	 */
	
	public List<T> executeQuery(String sql,PageBean pageBean,CallBack<T> callBack) throws Exception{
		Connection con=null;
		PreparedStatement ps=null;
		ResultSet rs=null;
		try {
			con=DBAccess.getConnection();
//			如果用户需要分页的话将用户传递过来的sql语句进行转换
			if(null!=pageBean&&pageBean.isPagination()) {
				String countSql = this.countSql(sql);
				ps=con.prepareStatement(countSql);
				rs=ps.executeQuery();
				if(rs.next()) {
					pageBean.setTotal(rs.getInt(1));
				}
				//开始查询结果
				String pageSql = this.pageSql(sql, pageBean);
				ps=con.prepareStatement(pageSql);
			}else {
				//用户不需要分页
				ps=con.prepareStatement(sql);
			}
			rs=ps.executeQuery();
			
		} catch (Exception e) {
			e.printStackTrace();
		}
		return callBack.forEach(rs);
	}

	
	/**
	 * 共用的方法用于执行sql语句实现增删改
	 * 通用编辑
	 * @param sql
	 * @return
	 */
	public int executeUpdate(String sql) {
		Connection con=null;
		PreparedStatement ps=null;
		ResultSet rs=null;
		int n=0;
		try {
			con=DBAccess.getConnection();
			ps=con.prepareStatement(sql);
			n=ps.executeUpdate();
		} catch (Exception e) {
			e.printStackTrace();
		}finally {
			DBAccess.close(con, ps, rs);
		}
		return n;
	}
	
	/**
	 * 将用户sql语句修改为查询满足条件的总条目数sql语句
	 * @param sql
	 * @return
	 */
	private String countSql(String sql) {
		String countSql="select count(*) from ("+sql+") a";
		return countSql;
	}
	
	private String pageSql(String sql,PageBean pageBean) {
		String pageSql="select * from ("+sql+")a limit "+pageBean.getStartIndex()+","+pageBean.getRows();
		return pageSql;
	}
	
	
	
	
	
	
	
	
	
}

这里以学生类为例在stuDao里面调用相关方法代码如下（studao继承了basedao）

package com.dff.dao;

import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.List;

import com.dff.entity.Student;
import com.dff.util.BaseDao;
import com.dff.util.PageBean;
import com.dff.util.StringUtils;

public class StudentDao extends BaseDao<Student>{
	/**
	 * 现状：增删改
	 * 	1.写sql
	 * 	2.建立链接
	 * 	3.预定义对象PreparedStatement
	 * 	4.设置参数
	 * 	5.执行sql
	 * 解决：
	 * 	
	 * @param student
	 * @throws Exception
	 */
	
	public void add(Student student) throws Exception {
		String sql="insert into t_student values(?,?,?,?,?)";
		super.executeUpdate(sql, student, new String[] {"sid","sname","snamePinyin","age","remark"});
	}
	
	public void delete(Student student) throws Exception {
		String sql="delete from t_student where sid=?";
		super.executeUpdate(sql, student, new String[] {"sid"});
	}
	
	public void edit(Student student) throws Exception {
		String sql="update t_student set sname=?,snamePinyin=?,age=?,remark=? where sid=?";
		super.executeUpdate(sql, student, new String[] {"sname","snamePinyin","age","remark","sid"});
	}
	
	/**
	 * 查询所有
	 * @param student
	 * @param pageIndex
	 * @param pageSize
	 * @return
	 */
	public List<Student> list(Student student,PageBean pageBean) throws Exception{
		
		
		String sql="select * from t_student where 1=1";
		if(StringUtils.isNotBlank(student.getSname())) {
			sql+=" and sname like '%"+student.getSname()+"%'";
		}
		return this.executeQuery(sql, pageBean, new CallBack<Student>() {
			@Override
			public List<Student> forEach(ResultSet rs) throws Exception {
				List<Student> students=new ArrayList<>();
				Student s=null;
				while(rs.next()) {
					s=new Student();
					s.setSid(rs.getInt("sid"));
					s.setSname(rs.getString("sname"));
					s.setAge(rs.getInt("age"));
					s.setRemark(rs.getString("remark"));
					students.add(s);
				}
				return students;
			}
		});
		
	}
	
	
	
	
	
	
	
	
	
	
	
	
}

在子控制器里面写相关方法

package com.dff.web;

import java.util.List;

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

import com.dff.dao.StudentDao;
import com.dff.entity.Student;
import com.dff.framework.ActionSupport;
import com.dff.framework.ModelDriver;
import com.dff.util.PageBean;

public class StudentAction extends ActionSupport implements ModelDriver<Student>{
	
	private Student student=new Student();
	private StudentDao studao=new StudentDao();
			
	@Override
	public Student getModel() {
		// TODO Auto-generated method stub
		return student;
	}
	
	public String add(HttpServletRequest req,HttpServletResponse resp) throws Exception {
		studao.add(student);
		return "toList";
		
	}
	
	public String delete(HttpServletRequest req,HttpServletResponse resp) throws Exception {
		studao.delete(student);
		return "toList";
		
	}
	
	public String edit(HttpServletRequest req,HttpServletResponse resp) throws Exception {
		studao.edit(student);
		return "toList";
		
	}
	
	public String list(HttpServletRequest req,HttpServletResponse resp) {
		PageBean pagebean=new PageBean();
		pagebean.setRequest(req);
		List<Student> list;
		try {
			list = studao.list(student, pagebean);
			req.setAttribute("students", list);
			req.setAttribute("pageBean", pagebean);		
		
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		return "list";
	
		
	}

	public String toEdit(HttpServletRequest req,HttpServletResponse resp) {
		//如果跳转地是新增界面无需查询，跳转地是修改界面，需要查询当前sid对应的
		if(student.getSid()!=0) {
			try {
				List<Student> list = studao.list(student, null);
				req.setAttribute("b", list.get(0));
			} catch (Exception e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
		
		return "toEdit";
		
	}

	
}

测试代码

public static void main(String[] args) throws Exception {
		Student student=new Student();
		student.setSid(100);
		student.setSname("aqqqq");
		student.setSnamePinyin("aaaaaa");
		student.setAge(100);
		student.setRemark("wu");
		StudentDao studao=new StudentDao();
		studao.add(student);
	}

界面

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
    <%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
    <%@taglib prefix="z" uri="/zking" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<link href="https://cdn.bootcdn.net/ajax/libs/twitter-bootstrap/3.1.0/css/bootstrap.css" rel="stylesheet">
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<script src="https://cdn.bootcdn.net/ajax/libs/jquery/3.0.0/jquery.js"></script>
<script src="https://cdn.bootcdn.net/ajax/libs/twitter-bootstrap/3.1.0/js/bootstrap.js"></script>
<title>Insert title here</title>
</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">
 <tr>
    <td>学生编号</td>
    <td>学生姓名</td>
    <td>姓名缩写</td>
    <td>学生年龄</td>
    <td>学生备注</td>
 </tr>
<c:forEach items="${students }" var="i">
   <tr>
    <td>${i.sid }</td>
    <td>${i.sname }</td>
    <td>${i.snamePinyin }</td>
    <td>${i.age }</td>
    <td>${i.remark }</td>
    <td>
		<a href="${pageContext.request.contextPath }/book.action?methodName=toEdit&sid=${i.sid}">修改</a>
		<a href="${pageContext.request.contextPath }/book.action?methodName=delete&sid=${i.sid}">删除</a>
	</td>
 </tr>
</c:forEach>


</table>
<z:pagination pageBean="${pageBean }"/>
</body>
</html>

绑定值?

?删除效果（把编号为2的删除了）

?修改拿值界面

遇到的问题

上面报错是因为配置路径写错了?

<forward name="list" path="/index.jsp" redirect="false" />? path路径我写成了/booklist.jsp 而我的项目里面根本没有这个页面