layui实现学生数据的展示（查找）和分页

数据库/表：

运行效果展示：

整体代码布局：

代码：

创建数据库：

#创建数据库
create database 70806_db
default character set utf8mb4 #设置字符集
default collate utf8mb4_general_ci #设置排序规则 

创建数据表：

#创建班级表
create table classInfo
(
	classId int primary key auto_increment,
	className varchar(20)
);

select * from classInfo;

insert into classInfo
(className)
values
('AAA01'),
('AAA02');

#创建学生表
create table studentInfo
(
	studentId int primary key auto_increment,
	name varchar(20) not null,
	sex char(1) not null,
	birthday date,
	province varchar(20) default '河南',
	classId int,
	foreign key (classId)
	references classInfo(classId)
);

select * from studentInfo;

insert into studentInfo
(name,sex,birthday,province,classId)
values
('张三','男','2002-01-01','湖北',1),
('李四','女','2003-01-05','河南',2),
('王五','男','2010-03-01','湖北',1),
('赵六','男','2009-01-08','河南',2),
('孙琪','女','2001-09-01','湖北',1);

util:

BaseDAO:

package com.util;

import javax.sql.DataSource;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.sql.*;
import java.util.*;

public class BaseDAO {

	//四大金刚
	//驱动类
	private static final String DRIVER="com.mysql.cj.jdbc.Driver";
	//连接地址
	private static final String URL="jdbc:mysql://localhost:3306/70806_db?useSSL=false&characterEncoding=utf8&serverTimezone=Asia/Shanghai";
	//用户名
	private static final String USER="root";
	//密码
	private static final String PASSWORD="123456";



	//获取连接
	public static Connection getConnection(){

		Connection con = null;

		try{
			//加载驱动类
			Class.forName(DRIVER);
			//获取连接
			con = DriverManager.getConnection(URL,USER,PASSWORD);
			
		}catch(Exception ex){
			ex.printStackTrace();
		}

		return con;
	}

	//关闭数据库对象
	public static void closeAll(Connection con,Statement st,ResultSet rs){
		
		if(rs!=null){
			try{
				rs.close();
			}catch(Exception ex){
				ex.printStackTrace();
			}
			
		}

		if(st!=null){

			try{
				st.close();
			}catch(Exception ex){
				ex.printStackTrace();
			}
			
		}

		if(con!=null){
			try{
				con.close();
			}catch(Exception ex){
				ex.printStackTrace();
			}
			
		}

	}


	//通用设置参数方法
	public static void setParams(PreparedStatement pst,Object[] params){

		if(params==null){
			return;
		}

		for(int i=0;i<params.length;i++){
			try{
				pst.setObject(i+1,params[i]);
			}catch(Exception ex){
				ex.printStackTrace();
			}
		}
	}


	//通用增删改
	public static int executeUpdate(String sql,Object[] params){

		Connection con = null;
		PreparedStatement pst = null;
		
		int res = -1;
		
		try{

			//获取连接
			con = getConnection();
			//创建预编译命令执行对象
			pst = con.prepareStatement(sql);
			//设置参数
			setParams(pst,params);
			//执行
			System.out.println(pst);
			res = pst.executeUpdate();

		}catch(Exception ex){
			ex.printStackTrace();
		}finally{
			closeAll(con,pst,null);
		}
		
		return res;
	}

	//获取总记录数的查询:select count(*) from ..
	public static int getTotal(String sql,Object[] params){
		int total = 0;

		Connection con = null;
		PreparedStatement pst = null;
		ResultSet rs = null;

		try{

			con = getConnection();
			pst = con.prepareStatement(sql);
			setParams(pst,params);
			rs = pst.executeQuery();
			//判断是否查询除了一个记录
			if(rs.next()){
				total = rs.getInt(1);
			}

		}catch (Exception ex){
			ex.printStackTrace();
		}finally {
			closeAll(con,pst,rs);
		}

		return total;
	}


	//通用查询
	public static List<Map<String,Object>> executeQuery(String sql,Object[] params) {

		List<Map<String,Object>> rows = new ArrayList<>();

		Connection con = null;
		PreparedStatement pst = null;
		ResultSet rs = null;

		try{
			//获取连接	
			con = getConnection();			
			//获取命令对象
			pst = con.prepareStatement(sql);
			//设置参数
			setParams(pst,params);
			//执行查询
			rs = pst.executeQuery();

			//通过rs获取结果集的结构信息
			ResultSetMetaData rsmd =  rs.getMetaData();
			//获取结果集的列数
			int colCount = rsmd.getColumnCount();

			//遍历查询结果，并封装到List<Map>中
			while(rs.next()){
				//用Map存储当前行的各个列数据
				Map<String,Object> map = new HashMap<>();
				//循环获取每一列的信息
				for(int i=1;i<=colCount;i++){
					//获取列名(使用rsmd)
					String colName = rsmd.getColumnLabel(i);
					//获取列值(使用rs)
					Object colVal = rs.getObject(i);
					//将当前列存储到map中
					map.put(colName,colVal);								
				}
				
				//将遍历的当前行的数据存储到List中
				rows.add(map);
							
			}


		}catch(Exception ex){
			ex.printStackTrace();
		}finally{
			closeAll(con,pst,rs);
		}
		
		return rows;

	}

}

entity:

Student :

package com.entity;

import java.util.Date;

public class Student {
    private Integer studentId;
    private String name;
    private String sex;
    private Date birthday;
    private String province;
    private Integer classId;

    public Student() {
    }

    public Student(Integer studentId, String name, String sex, Date birthday, String province, Integer classId) {
        this.studentId = studentId;
        this.name = name;
        this.sex = sex;
        this.birthday = birthday;
        this.province = province;
        this.classId = classId;
    }

    public Student(String name, String sex, Date birthday, String province, Integer classId) {
        this.name = name;
        this.sex = sex;
        this.birthday = birthday;
        this.province = province;
        this.classId = classId;
    }

    public Integer getStudentId() {
        return studentId;
    }

    public void setStudentId(Integer studentId) {
        this.studentId = studentId;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }

    public Date getBirthday() {
        return birthday;
    }

    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }

    public String getProvince() {
        return province;
    }

    public void setProvince(String province) {
        this.province = province;
    }

    public Integer getClassId() {
        return classId;
    }

    public void setClassId(Integer classId) {
        this.classId = classId;
    }

    @Override
    public String toString() {
        return "Student{" +
                "studentId=" + studentId +
                ", name='" + name + '\'' +
                ", sex='" + sex + '\'' +
                ", birthday=" + birthday +
                ", province='" + province + '\'' +
                ", classId=" + classId +
                '}';
    }
}

ClassInfo :

package com.entity;

public class ClassInfo {
    private Integer classId;
    private String className;

    public ClassInfo() {
    }

    public ClassInfo(String className) {
        this.className = className;
    }

    public ClassInfo(Integer classId, String className) {
        this.classId = classId;
        this.className = className;
    }

    public Integer getClassId() {
        return classId;
    }

    public void setClassId(Integer classId) {
        this.classId = classId;
    }

    public String getClassName() {
        return className;
    }

    public void setClassName(String className) {
        this.className = className;
    }

    @Override
    public String toString() {
        return "ClassInfo{" +
                "classId=" + classId +
                ", className='" + className + '\'' +
                '}';
    }
}

CommonResult:

package com.entity;

public class CommonResult {
    //编码:0成功，1失败
    private Integer code;
    //提示消息
    private String msg;
    //记录数
    private Integer count;
    //记录数据
    private Object data;

    public CommonResult() {
    }

    public CommonResult(Integer code, String msg, Integer count, Object data) {
        this.code = code;
        this.msg = msg;
        this.count = count;
        this.data = data;
    }

    public CommonResult(String msg, Integer count, Object data) {
        this.msg = msg;
        this.count = count;
        this.data = data;
    }

    public Integer getCode() {
        return code;
    }

    public void setCode(Integer code) {
        this.code = code;
    }

    public String getMsg() {
        return msg;
    }

    public void setMsg(String msg) {
        this.msg = msg;
    }

    public Integer getCount() {
        return count;
    }

    public void setCount(Integer count) {
        this.count = count;
    }

    public Object getData() {
        return data;
    }

    public void setData(Object data) {
        this.data = data;
    }

    @Override
    public String toString() {
        return "CommonResult{" +
                "code=" + code +
                ", msg='" + msg + '\'' +
                ", count=" + count +
                ", data=" + data +
                '}';
    }
}

PageData:

package com.entity;

public class PageData {
    //当前页码
    private Integer pageNo;
    //每页记录数
    private Integer pageSize;
    //总记录数
    private Integer totalCount;
    //总页数
    private Integer totalPage;
    //当前页记录
    private Object data;

    public PageData() {
    }

    public Integer getPageNo() {
        return pageNo;
    }

    public void setPageNo(Integer pageNo) {
        this.pageNo = pageNo;
    }

    public Integer getPageSize() {
        return pageSize;
    }

    public void setPageSize(Integer pageSize) {
        this.pageSize = pageSize;
    }

    public Integer getTotalCount() {
        return totalCount;
    }

    public void setTotalCount(Integer totalCount) {
        this.totalCount = totalCount;
    }

    public Integer getTotalPage() {
        return totalPage;
    }

    public void setTotalPage(Integer totalPage) {
        this.totalPage = totalPage;
    }

    public Object getData() {
        return data;
    }

    public void setData(Object data) {
        this.data = data;
    }

    @Override
    public String toString() {
        return "PageData{" +
                "pageNo=" + pageNo +
                ", pageSize=" + pageSize +
                ", totalCount=" + totalCount +
                ", totalPage=" + totalPage +
                ", data=" + data +
                '}';
    }
}

dao:

impl:

StudentDAOImpl:

package com.dao.impl;

import com.dao.IStudentDAO;
import com.entity.PageData;
import com.entity.Student;
import com.util.BaseDAO;

import java.util.List;
import java.util.Map;

public class StudentDAOImpl implements IStudentDAO {

    @Override
    public List<Map<String, Object>> listAll() {
        System.out.println("=======StudentDAOImpl listAll===============");
        String sql = "select s.studentId,s.name,s.sex,s.birthday,s.province," +
                "     c.classId,c.className " +
                "     from studentInfo s " +
                "     join classInfo c " +
                "     on s.classId = c.classId ";
        System.out.println(sql);
        return BaseDAO.executeQuery(sql,null);
    }

    @Override
    public int insert(Student student) {
        String sql="insert into studentInfo "+
                "   (name,sex,birthday,province,classId)"+
                "   values"+
                "   (?,?,?,?,?)";
        Object[] params={
                student.getName(),
                student.getSex(),
                student.getBirthday(),
                student.getProvince(),
                student.getClassId()
        };
        return BaseDAO.executeUpdate(sql,params);
    }

    @Override
    public int update(Student student) {
        String sql = "update studentInfo" +
                "     set name = ?," +
                "         sex = ?," +
                "         birthday = ?," +
                "         province  = ?," +
                "         classId = ? " +
                "     where studentId = ? ";
        Object[] params = {
                student.getName(),
                student.getSex(),
                student.getBirthday(),
                student.getProvince(),
                student.getClassId(),
                student.getStudentId()
        };
        return BaseDAO.executeUpdate(sql,params);
    }

    @Override
    public PageData queryByPage(Integer pageNo, Integer pageSize) {
        //获取总记录数
        String totalSql = "select count(*) from studentInfo ";
        //总记录数
        Integer totalCount = BaseDAO.getTotal(totalSql,null);
        //总页数
        Integer totalPage = totalCount%pageSize==0?totalCount/pageSize:totalCount/pageSize+1;

        //分页查询
        String pageSql = "select s.studentId,s.name,s.sex,s.birthday,s.province," +
                "     c.classId,c.className " +
                "     from studentInfo s " +
                "     join classInfo c " +
                "     on s.classId = c.classId " +
                "     order by s.studentId " +
                "     limit ?,? ";
        int start = (pageNo-1)*pageSize;
        Object[] params = {start,pageSize};
        List<Map<String,Object>> rows = BaseDAO.executeQuery(pageSql,params);

        //封装分页数据对象
        PageData pd = new PageData();
        pd.setPageNo(pageNo);
        pd.setPageSize(pageSize);
        pd.setTotalPage(totalPage);
        pd.setTotalCount(totalCount);
        pd.setData(rows);

        return pd;
    }

}

ClassInfoDAOImpl:

package com.dao.impl;

import com.dao.IClassInfoDAO;
import com.util.BaseDAO;

import java.util.List;
import java.util.Map;

public class ClassInfoDAOImpl implements IClassInfoDAO {
    @Override
    public List<Map<String, Object>> listAll() {
        String sql="select classId,className from classInfo";
        return BaseDAO.executeQuery(sql,null);
    }
}

IStudentDAO:

package com.dao;

import com.entity.PageData;
import com.entity.Student;

import java.util.List;
import java.util.Map;

public interface IStudentDAO {
    List<Map<String,Object>> listAll();

    int insert(Student student);

    int update(Student student);

    PageData queryByPage(Integer pageNo, Integer pageSize);


}

IClassInfoDAO:

package com.dao;

import java.util.List;
import java.util.Map;

public interface IClassInfoDAO {
    List<Map<String ,Object>> listAll();
}

service:

impl:

StudentServiceImpl:

package com.service.impl;

import com.dao.IStudentDAO;
import com.dao.impl.StudentDAOImpl;
import com.entity.PageData;
import com.entity.Student;
import com.service.IStudentService;
import com.util.BaseDAO;

import java.util.List;
import java.util.Map;

public class StudentServiceImpl implements IStudentService {
    private IStudentDAO studentDAO=new StudentDAOImpl();

    @Override
    public int update(Student student) {
        return studentDAO.update(student);
    }

    @Override
    public PageData queryByPage(Integer pageNo, Integer pageSize) {
        return studentDAO.queryByPage(pageNo,pageSize);
    }

    @Override
    public int add(Student student) {
        return studentDAO.insert(student);
    }

    @Override
    public List<Map<String, Object>> listAll() {
        return studentDAO.listAll();
    }

}

ClassInfoServiceImpl:

package com.service.impl;

import com.dao.IClassInfoDAO;
import com.dao.impl.ClassInfoDAOImpl;
import com.service.IClassInfoService;

import java.util.List;
import java.util.Map;

public class ClassInfoServiceImpl implements IClassInfoService {
    private IClassInfoDAO classInfoDAO=new ClassInfoDAOImpl();
    @Override
    public List<Map<String, Object>> listAll() {
        return classInfoDAO.listAll();
    }
}

IStudentService:

package com.service;

import com.entity.PageData;
import com.entity.Student;


import java.util.List;
import java.util.Map;

public interface IStudentService {
    List<Map<String,Object>> listAll();

    //添加学生
    int add(Student student);

    int update(Student student);

    PageData queryByPage(Integer pageNo, Integer pageSize);

}

IClassInfoService:

package com.service;

import java.util.List;
import java.util.Map;

public interface IClassInfoService {
    List<Map<String,Object>> listAll();
}

servlet:

StudentServlet:

package com.servlet;

import com.alibaba.fastjson.JSONObject;
import com.entity.CommonResult;
import com.entity.PageData;
import com.entity.Student;
import com.mysql.cj.util.StringUtils;
import com.service.IStudentService;
import com.service.impl.StudentServiceImpl;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;

@WebServlet(urlPatterns = "/StudentServlet/*")
public class StudentServlet extends HttpServlet {
    private IStudentService studentService = new StudentServiceImpl();

    @Override
    protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //获取请求方法
        String uri = req.getRequestURI();
        String process = uri.substring(uri.lastIndexOf("/")+1);

        System.out.println("proccess:"+process);

//        //设置响应编码
//        resp.setContentType("text/html;charset=utf-8");

        //定义处理之后返回的数据对象
        Object data = null;

        switch (process){
            case "query":
                data = this.query(req,resp);
                break;
            case "queryByPage":
                data = this.queryByPage(req,resp);
                break;
            case "queryForLayUI":
                data = this.queryForLayUI(req,resp);
                break;
            case "add":
                data=this.add(req,resp);
                break;
            case "update":
                data = this.update(req,resp);
                break;
        }

        System.out.println("data:"+data);
        //将数据转为json字符串
        String jsonStr = JSONObject.toJSONStringWithDateFormat(data,"yyyy-MM-dd");
        System.out.println(jsonStr);
        PrintWriter out = resp.getWriter(); //获取输出流对象
        out.println(jsonStr); //输出json字符串给浏览器
        out.flush(); //清空缓存
        out.close();//关闭流对象
    }

    private Object queryForLayUI(HttpServletRequest req, HttpServletResponse resp) {
        //获取前端传入的分页参数
        String pageNo = req.getParameter("page");
        String pageSize = req.getParameter("limit");
        //判断参数是否有效
        Integer pn = StringUtils.isNullOrEmpty(pageNo)?1:Integer.parseInt(pageNo);
        Integer ps = StringUtils.isNullOrEmpty(pageSize)?3:Integer.parseInt(pageSize);

        PageData pd =  studentService.queryByPage(pn,ps);

        return new CommonResult(0,"success",pd.getTotalCount(),pd.getData());
    }

    private Object queryByPage(HttpServletRequest req, HttpServletResponse resp) {
        //获取前端传入的分页参数
        String pageNo = req.getParameter("pageNo");
        String pageSize = req.getParameter("pageSize");
        //判断参数是否有效
        Integer pn = StringUtils.isNullOrEmpty(pageNo)?1:Integer.parseInt(pageNo);
        Integer ps = StringUtils.isNullOrEmpty(pageSize)?3:Integer.parseInt(pageSize);

        return studentService.queryByPage(pn,ps);
    }

    private Object update(HttpServletRequest req, HttpServletResponse resp) {
        System.out.println("111");
        //获取传入的数据
        Integer studentId = Integer.parseInt(req.getParameter("studentId"));
        String name = req.getParameter("name");
        String sex = req.getParameter("sex");
        Date birthday = java.sql.Date.valueOf(req.getParameter("birthday"));
        String province = req.getParameter("province");
        Integer classId = Integer.parseInt(req.getParameter("classId"));

        //封装实体对象
        Student student = new Student(
                studentId,name,sex,birthday,province,classId
        );

        //调用业务层保存数据
        int count = studentService.update(student);
        System.out.println("count:"+count);

        //定义结果数据
        Map<String,Object> res = new HashMap<>();
        //添加成功
        if(count==1){
            //code为0说明处理成功
            res.put("code",0);
        }else{
            //code为1处理失败
            res.put("code",1);
        }
        System.out.println("res:"+res);
        return res;
    }

    //添加
    private Object add(HttpServletRequest req, HttpServletResponse resp) {
        //获取传入的数据
        String name=req.getParameter("name");
        String sex=req.getParameter("sex");
        Date birthday=java.sql.Date.valueOf(req.getParameter("birthday"));
        String province=req.getParameter("province");
        Integer classId=Integer.parseInt(req.getParameter("classId"));

        //封装实体对象
        Student student=new Student(
                name,sex,birthday,province,classId
        );

        //调用业务层保存数据
        int count= studentService.add(student);

        //定义数据结果
        Map<String,Object> res=new HashMap<>();
        //添加成功
        if(count==1){
            //code为0说明处理成功
            res.put("code",0);
        }else{
            //code为1处理失败x`
            res.put("code",1);
        }
        return res;

    }

    /**
     * 执行查询
     * @param req
     * @param resp
     * @return
     */
    private Object query(HttpServletRequest req, HttpServletResponse resp) {
        System.out.println("=====StudentServlet query=======");
        return studentService.listAll();
    }
}

ClassInfoServlet:

package com.servlet;

import com.alibaba.fastjson.JSONObject;
import com.mysql.cj.xdevapi.JsonString;
import com.service.IClassInfoService;
import com.service.impl.ClassInfoServiceImpl;


import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;

@WebServlet("/ClassInfoServlet/*")
public class ClassInfoServlet extends HttpServlet {
    //业务层对象
    private IClassInfoService classInfoService=new ClassInfoServiceImpl();
    @Override
    protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        String uri=req.getRequestURI();
        String process=uri.substring(uri.lastIndexOf("/")+1);
        //定义结果对象
        Object date=null;
        switch (process){
            case "query":
                date=query(req,resp);
                break;
        }

        //输出json字符串
        String jsonStr= JSONObject.toJSONString(date);
        PrintWriter out=resp.getWriter();
        out.println(jsonStr);
        out.flush();
        out.close();

    }

    //查村
    private Object query(HttpServletRequest req, HttpServletResponse resp) {
        return classInfoService.listAll();
    }
}

filter:

CharacterEncodingFilter:

package com.filter;

import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import java.io.IOException;

@WebFilter("/*")
public class CharacterEncodingFilter implements Filter {
    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        //设置编码
        servletRequest.setCharacterEncoding("utf-8");
        servletResponse.setContentType("text/html;charset=utf-8");
        //向后传递请求
        filterChain.doFilter(servletRequest,servletResponse);
    }
}

web:

lay6.jsp:

<%--
  Created by IntelliJ IDEA.
  User: 33154
  Date: 2022/8/9
  Time: 8:52
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
    <!-- 引入 layui.css -->
    <link rel="stylesheet" type="text/css" href="${pageContext.request.contextPath}/assets/plugins/layui-v2.6.8/layui/css/layui.css">
</head>
<body>

<!--要渲染的数据表格-->
<table id="stu"></table>

<!--弹出表单-->


<!-- 引入 layui.js -->
<script type="text/javascript" src="${pageContext.request.contextPath}/assets/plugins/layui-v2.6.8/layui/layui.js"></script>
<script>
    layui.use('table', function(){
        var table = layui.table;

        //渲染表格数据
        table.render({
            elem: '#stu' //渲染的目标元素
            ,url: '${pageContext.request.contextPath}/StudentServlet/queryForLayUI' //发送请求获取数据
            ,cellMinWidth: 80 //全局定义常规单元格的最小宽度，layui 2.2.1 新增
            ,page:true //启用分页
            ,cols: [[  //表格列的定义
                {field:'studentId', width:80, title: '学号', sort: true}
                ,{field:'name', width:80, title: '姓名'}
                ,{field:'sex', width:80, title: '性别', sort: true,templet:function (d){
                        console.log(d);
                        if(d.sex=="男")
                            return "<font color='blue'>男</font>";
                        else
                            return "<font color='red'>女</font>";
                    }}
                ,{field:'province', width:80, title: '省份'}
                ,{field:'birthday', title: '生日', width: '30%', minWidth: 100} //minWidth：局部定义当前单元格的最小宽度，layui 2.2.1 新增
                ,{field:'classId', title: '班级编号', hidden:true}
                ,{field:'className', title: '班级名字', sort: true}
            ]]
        });
    });
</script>
</body>
</html>

// A code block
var foo = 'bar';

// A code block
var foo = 'bar';

// A code block
var foo = 'bar';