自定义mvc增删改查

一、搭建自定义mvc框架环境
二、基础的增删改
三、通用的增删改
四、查询删除及重复表单提交问题
五、新增修改的前端实现

一、搭建自定义mvc框架环境

首先导入自定义mvcjar包，然后导入jar包需要的依赖，

然后再导入通用分页的类

配置web.xml



  Yzp_mvc_crud
 
  	mvc
  	com.yzp.framework.DispatcherServlet
  	
  		configLocation
  		/yzp.xml
  	
  
  
  mvc
  *.action

配置文件yzp.xml

二、基础的增删改

下面展示基础增删改代码。

package com.yzp.dao;

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

import com.yzp.entity.Stu;
import com.yzp.util.BaseDao;
import com.yzp.util.DBAccess;
import com.yzp.util.PageBean;
import com.yzp.util.StringUtils;


public class StuDao extends BaseDao {

	
	//查询
	public List list(Stu stu,PageBean pagebean) throws Exception{
		String sql = "select * from tb_stu where 1=1";
		String sname=stu.getSname();
		if(StringUtils.isNotBlank(sname)) {
			sql+=" and sname like '%"+sname+"%' ";
		}
		int sid = stu.getSid();
		//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(sid!=0) {
			sql+=" and sid ="+sid;
		}
		return super.executeQuery(sql, pagebean, rs ->{
			List list = new ArrayList<>();
			try {
				while(rs.next()) {
					list.add(new Stu(rs.getInt("sid"), rs.getString("sname"), rs.getInt("jid"), rs.getInt("bid"), rs.getString("hid")));
				}
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
			return list;
		});
	}
	
	//增
	public int add(Stu stu) throws Exception {
		Connection con = DBAccess.getConnection();
		String sql = "insert into tb_stu values(?,?,?,?,?)";
		PreparedStatement ps = con.prepareStatement(sql);
		ps.setObject(1, stu.getSid());
		ps.setObject(2, stu.getSname());
		ps.setObject(3, stu.getJid());
		ps.setObject(4, stu.getBid());
		ps.setObject(5, stu.getHid());
		return ps.executeUpdate();
	}
//	public int add(Stu stu) throws Exception {
//		Connection con = DBAccess.getConnection();
//		String sql = "insert into tb_stu values(?,?,?,?,?)";
//		return super.executeUpdate(sql, stu, new String[] {"sid","sname","jid","bid","hid"});
//	}
	//删
	public int del(Stu stu) throws Exception {
		Connection con = DBAccess.getConnection();
		String sql = "delete from tb_stu where sid=?";
		PreparedStatement ps = con.prepareStatement(sql);
		ps.setObject(1, stu.getSid());
		return ps.executeUpdate();
	}
	
//	public int del(Stu stu) throws Exception {
//		String sql = "delete from tb_stu where sid=?";
//		return super.executeUpdate(sql, stu,new String[] {"sid"});
//	}
	//改
	public int edit(Stu stu) throws Exception {
		Connection con = DBAccess.getConnection();
		String sql = "update tb_stu set sname=?,jid=?,bid=?,hid=? where sid=?";
		PreparedStatement ps = con.prepareStatement(sql);
		ps.setObject(1, stu.getSname());
		ps.setObject(2, stu.getJid());
		ps.setObject(3, stu.getBid());
		ps.setObject(4, stu.getHid());
		ps.setObject(5, stu.getSid());
		return ps.executeUpdate();
	}
//	public int edit(Stu stu) throws Exception {
//		String sql = "update tb_stu set sname=?,jid=?,bid=?,hid=? where sid=?";
//		return super.executeUpdate(sql, stu, new String[] {"sname","jid","bid","hid","sid"});
//	}
	
	
}

三、通用的增删改

在basedao里面写一个==public int executeUpdate(String sql,T t,String[] attrs) ==的方法，然后写dao方法的时候返回即可
下面展示 basedao代码片。

public int executeUpdate(String sql,T t,String[] attrs) throws Exception {
		Connection con = DBAccess.getConnection();
		PreparedStatement ps = con.prepareStatement(sql);
		//将t的某一个属性对应值加到pst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));

		}
//		ps.setObject(2, stu.getSname());
//		ps.setObject(3, stu.getJid());
//		ps.setObject(4, stu.getBid());
//		ps.setObject(5, stu.getHid());
		return ps.executeUpdate();
	}

下面展示studao代码。

package com.yzp.dao;

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

import com.yzp.entity.Stu;
import com.yzp.util.BaseDao;
import com.yzp.util.DBAccess;
import com.yzp.util.PageBean;
import com.yzp.util.StringUtils;


public class StuDao extends BaseDao {

	
	//查询
	public List list(Stu stu,PageBean pagebean) throws Exception{
		String sql = "select * from tb_stu where 1=1";
		String sname=stu.getSname();
		if(StringUtils.isNotBlank(sname)) {
			sql+=" and sname like '%"+sname+"%' ";
		}
		int sid = stu.getSid();
		//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(sid!=0) {
			sql+=" and sid ="+sid;
		}
		return super.executeQuery(sql, pagebean, rs ->{
			List list = new ArrayList<>();
			try {
				while(rs.next()) {
					list.add(new Stu(rs.getInt("sid"), rs.getString("sname"), rs.getInt("jid"), rs.getInt("bid"), rs.getString("hid")));
				}
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
			return list;
		});
	}
	
	//增
//	public int add(Stu stu) throws Exception {
//		Connection con = DBAccess.getConnection();
//		String sql = "insert into tb_stu values(?,?,?,?,?)";
//		PreparedStatement ps = con.prepareStatement(sql);
//		ps.setObject(1, stu.getSid());
//		ps.setObject(2, stu.getSname());
//		ps.setObject(3, stu.getJid());
//		ps.setObject(4, stu.getBid());
//		ps.setObject(5, stu.getHid());
//		return ps.executeUpdate();
//	}
	public int add(Stu stu) throws Exception {
		Connection con = DBAccess.getConnection();
		String sql = "insert into tb_stu values(?,?,?,?,?)";
		return super.executeUpdate(sql, stu, new String[] {"sid","sname","jid","bid","hid"});
	}
	//删
//	public int del(Stu stu) throws Exception {
//		Connection con = DBAccess.getConnection();
//		String sql = "delete from tb_stu where sid=?";
//		PreparedStatement ps = con.prepareStatement(sql);
//		ps.setObject(1, stu.getSid());
//		return ps.executeUpdate();
//	}
	
	public int del(Stu stu) throws Exception {
		String sql = "delete from tb_stu where sid=?";
		return super.executeUpdate(sql, stu,new String[] {"sid"});
	}
	//改
//	public int edit(Stu stu) throws Exception {
//		Connection con = DBAccess.getConnection();
//		String sql = "update tb_stu set sname=?,jid=?,bid=?,hid=? where sid=?";
//		PreparedStatement ps = con.prepareStatement(sql);
//		ps.setObject(1, stu.getSname());
//		ps.setObject(2, stu.getJid());
//		ps.setObject(3, stu.getBid());
//		ps.setObject(4, stu.getHid());
//		ps.setObject(5, stu.getSid());
//		return ps.executeUpdate();
//	}
	public int edit(Stu stu) throws Exception {
		String sql = "update tb_stu set sname=?,jid=?,bid=?,hid=? where sid=?";
		return super.executeUpdate(sql, stu, new String[] {"sname","jid","bid","hid","sid"});
	}
	
	
}

四、查询删除及重复表单提交问题

下面展示代码。

package com.yzp.web;

import java.util.List;

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

import com.yzp.dao.StuDao;
import com.yzp.entity.Stu;
import com.yzp.framework.ActionSupport;
import com.yzp.framework.ModelDriver;
import com.yzp.util.PageBean;

public class StuAction extends ActionSupport implements ModelDriver {

	private Stu stu = new Stu();
	private StuDao  sd = new StuDao();
	@Override
	public Stu getModel() {
		return stu;
	}

	//增加
	public String add(HttpServletRequest req, HttpServletResponse resp) {
		try {
			sd.add(stu);
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		//代表跳到查询界面
		return "tolist";
	}
	
	//删
	public String del(HttpServletRequest req, HttpServletResponse resp) {
		try {
			sd.del(stu);
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		//代表跳到查询界面
		return "tolist";
	}
	
	//修改
	public String edit(HttpServletRequest req, HttpServletResponse resp) {
		try {
			sd.edit(stu);
		} catch (Exception e) {
			// TODO Auto-generated catch block
			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 = sd.list(stu, pagebean);
			req.setAttribute("list", list);
			req.setAttribute("pagebean", pagebean);
		} catch (Exception e) {
			// TODO Auto-generated catch block
			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 sid = stu.getSid();
			if(sid!=0) {
				//传递sid到后台，有且只能查出一条数据，那也就意味着集合只有一条
				List list = sd.list(stu, null);
				req.setAttribute("b", list.get(0));
			}
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		//代表跳到编辑界面
		return "toEdit";
	}
}

五、新增修改的前端实现

下面展示一些内联代码片。

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>




Insert title here


 
 sid:

 sname:

 jid:

 bid:

 hid:

自定义mvc增删改查

Java相关栏目本月热门文章