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1.数据库表如下

CREATE TABLE `employee` (  `id` int(11) NOT NULL AUTO_INCREMENT,  `name` varchar(40) NOT NULL,  `note` varchar(200) DEFAULT NULL,  PRIMARY KEY (`id`)) ENGINE=InnoDB AUTO_INCREMENT=10 DEFAULT CHARSET=utf8;

2.项目的目录结构

5 个后端文件和 1 个前端文件。

简单前端页面，完整后端功能。

3.完整代码

实体类 Employee

/** * @author :hly * @github :https://github.com/huangliangyun * @blog :blog.csdn.net/Sirius_hly * @date :2018/11/29 */public class Employee {    private int id;    private String name;    private String note;    public Employee() {    }    public int getId() {        return id;    }    public void setId(int id) {        this.id = id;    }    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }    public String getNote() {        return note;    }    public void setNote(String note) {        this.note = note;    }    @Override    public String toString() {        return "Employee{" +                "id=" + id +                ", name='" + name + '\'' +                ", note='" + note + '\'' +                '}';    }}

数据库连接类 DBConnection

package com.hly.jsp.javaWeb.dao;import java.sql.*;/** * @author :hly * @github :https://github.com/huangliangyun * @blog :blog.csdn.net/Sirius_hly * @date :2018/10/31 */public class DBConnection {    private static final String driverName = "com.mysql.jdbc.Driver";    private static final String url = "jdbc:mysql://localhost:3306/testDB?useUnicode=true&characterEncoding=UTF-8";    private static final String user = "root";    private static final String password = "roof";    private static Connection connection = null;    /*static {        try {            Class.forName(driverName);        } catch (ClassNotFoundException e) {            System.out.println("连接失败"+e.getMessage());        }    }*/    public static Connection getConnection() throws SQLException {        try {            Class.forName(driverName);            connection = DriverManager.getConnection(url, user, password);;        } catch (ClassNotFoundException e) {            e.printStackTrace();        }        return connection;    }    public static void close(ResultSet rs, Statement st, Connection conn) {        try {            if (rs != null) {                rs.close();            }        } catch (SQLException e) {            e.printStackTrace();        } finally {            try {                if (st != null) {                    st.close();                }            } catch (SQLException e) {                e.printStackTrace();            } finally {                if (conn != null) {                    try {                        conn.close();                    } catch (SQLException e) {                        e.printStackTrace();                    }                }            }        }    }}

EmployeeDao 数据接口层

package com.hly.jsp.javaWeb.dao;import com.hly.jsp.javaWeb.entity.Employee;import java.util.List;/** * @author :hly * @github :https://github.com/huangliangyun * @blog :blog.csdn.net/Sirius_hly * @date :2018/11/29 */public interface EmployeeDao {    //C    public int add(Employee employee);    //R    public List
   
     selectAll();    public List
    
      query(String name);    //U    public int  update(Employee employee);    //D    public int delete (int id);}
    
   

dao 层实现类 EmployeeDaoImpl，SQL 语句的实现

package com.hly.jsp.javaWeb.impl;import com.hly.jsp.javaWeb.dao.DBConnection;import com.hly.jsp.javaWeb.dao.EmployeeDao;import com.hly.jsp.javaWeb.entity.Employee;import java.sql.Connection;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.sql.SQLException;import java.util.ArrayList;import java.util.List;/** * @author :hly * @github :https://github.com/huangliangyun * @blog :blog.csdn.net/Sirius_hly * @date :2018/11/29 */public class EmployeeDaoImpl implements EmployeeDao {    //增    @Override    public int add(Employee employee) {        try {            Connection con = DBConnection.getConnection();            String sql = "insert into employee(name,note) values(?,?)";            PreparedStatement ps = con.prepareStatement(sql);            ps.setString(1, employee.getName());            ps.setString(2, employee.getNote());            ps.executeUpdate();            DBConnection.close(null,ps,con);        } catch (SQLException e) {            e.printStackTrace();        }        return 1;    }    //查全部    @Override    public List
   
     selectAll() {        List
    
      list = new ArrayList<>();        Employee employee = null;        try {            Connection con = DBConnection.getConnection();            String sql = "select id,name,note from employee";            PreparedStatement ps = con.prepareStatement(sql);            ResultSet rs = ps.executeQuery();            while (rs.next()){                employee = new Employee();                employee.setId(rs.getInt(1));                employee.setName(rs.getString(2));                employee.setNote(rs.getString(3));                list.add(employee);            }            DBConnection.close(rs,ps,con);        } catch (SQLException e) {            e.printStackTrace();        }        return list;    }    //根据 id 查    @Override    public List
     
       query(String name) {        Employee employee = null;        List
      
        list = new ArrayList<>();        try {            Connection con = DBConnection.getConnection();            String sql = "select id,name,note from employee where name like ?";            PreparedStatement ps = con.prepareStatement(sql);            //模糊查询            ps.setString(1,"%"+name+"%");            ResultSet rs = ps.executeQuery();            while (rs.next()){                employee = new Employee();                employee.setId(rs.getInt(1));                employee.setName(rs.getString(2));                employee.setNote(rs.getString(3));                list.add(employee);            }            DBConnection.close(rs,ps,con);        } catch (SQLException e) {            e.printStackTrace();        }        return list;    }    //更新    @Override    public int update(Employee employee) {        try {            Connection con = DBConnection.getConnection();            String sql = "update employee set name = ?,note = ? where id = ?";            PreparedStatement ps = con.prepareStatement(sql);            ps.setString(1,employee.getName());            ps.setString(2,employee.getNote());            ps.setInt(3,employee.getId());            ps.executeUpdate();            DBConnection.close(null,ps,con);        } catch (SQLException e) {            e.printStackTrace();        }        return 1;    }    //删除    @Override    public int delete(int id) {        try {            Connection con = DBConnection.getConnection();            String sql = "delete from employee where id = ?";            PreparedStatement ps = con.prepareStatement(sql);            ps.setInt(1,id);            ps.executeUpdate();            DBConnection.close(null,ps,con);        } catch (SQLException e) {            e.printStackTrace();        }        return 1;    }}
      
     
    
   

控制层 Servlet

EmployeeServlet

package com.hly.jsp.javaWeb.controller;import com.hly.jsp.javaWeb.dao.EmployeeDao;import com.hly.jsp.javaWeb.entity.Employee;import com.hly.jsp.javaWeb.impl.EmployeeDaoImpl;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.lang.reflect.Method;import java.util.List;/** * @author :hly * @github :https://github.com/huangliangyun * @blog :blog.csdn.net/Sirius_hly * @date :2018/11/28 */@WebServlet(urlPatterns = { "*.do" })public class EmployeeServlet extends HttpServlet {    public void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException {        response.setContentType("text/html;charset=UTF-8");        doGet(request, response);    }    public void doGet(HttpServletRequest request, HttpServletResponse response) {        response.setContentType("text/html;charset=utf-8");        String url = request.getRequestURI();        String methodName = url.substring(url.lastIndexOf("/")+1, url.lastIndexOf("."));        Method method = null;        try {            // 使用反射机制获取在本类中声明了的方法            method = getClass().getDeclaredMethod(methodName, HttpServletRequest.class, HttpServletResponse.class);            // 执行方法            method.invoke(this, request, response);        } catch (Exception e) {            throw new RuntimeException("调用方法出错");        }    }    //增加    public void addEmp(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {        Employee employee = new Employee();        employee.setName(request.getParameter("addName"));        employee.setNote(request.getParameter("addNote"));        EmployeeDao employeeDao = new EmployeeDaoImpl();        employeeDao.add(employee);        selectAllEmp(request,response);    }    //查找全部    public void selectAllEmp(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {        EmployeeDao employeeDao = new EmployeeDaoImpl();        List
   
     list = employeeDao.selectAll();        request.setAttribute("list", list);        request.getRequestDispatcher("/javaWeb/manage/main.jsp").forward(request, response);    }    //模糊查询    public void selectByEmpName(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {        String name = request.getParameter("selectName");        EmployeeDao employeeDao = new EmployeeDaoImpl();        List
    
      list = employeeDao.query(name);        System.err.println("list："+list);        request.setAttribute("list", list);        request.getRequestDispatcher("/javaWeb/manage/main.jsp").forward(request, response);    }    //更新数据    public void updateEmp(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {        Employee employee = new Employee();        employee.setId(Integer.parseInt(request.getParameter("updateId")));        employee.setName(request.getParameter("updateName"));        employee.setNote(request.getParameter("updateNote"));        System.err.println(employee);        EmployeeDao employeeDao = new EmployeeDaoImpl();        employeeDao.update(employee);        selectAllEmp(request,response);    }    //删除    public void deleteEmp(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {        String deleteId = request.getParameter("deleteId");        EmployeeDao employeeDao = new EmployeeDaoImpl();        employeeDao.delete(Integer.parseInt(deleteId));        selectAllEmp(request,response);    }}
    
   

前端代码 main.js

<%@ page contentType="text/html;charset=UTF-8" language="java" %><%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>        点击查询所有用户信息
   
    
        
    
   
   
    
        
        
    
   
   
    
        
        
        
    
   
           
   
   
        
     
              
id
              
name
              
note
              
delete
         
         
                  
${e.id}
                  
${e.name}
                  
${e.note}
                  
删除
             
        
   

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