简单的增删改查及数据分页

一、结构图
二、相关代码
- - ① User类
  - ② Page类
  - ③ UserDao类
  - ④ CodeFilter类
  - ⑤ UserService 类
  - ⑥ IndexServlet 类
  - ⑦ UserDeleteServlet 类
  - ⑧ UserEditServlet 类
  - ⑨ edit.jsp
  - ⑩ index.jsp
  - ⑩① web.xml
  - ⑩② pom.xml
三、效果截图

一、结构图

二、相关代码 ① User类

package com.allen.entity;
import java.util.Date;
public class User {

    private Integer id;
    private String trueName;
    private String loginName;
    private String loginPassword;
    private Integer role;
    private Date createTime;
    private Date updateTime;

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getTrueName() {
        return trueName;
    }

    public void setTrueName(String trueName) {
        this.trueName = trueName;
    }

    public String getLoginName() {
        return loginName;
    }

    public void setLoginName(String loginName) {
        this.loginName = loginName;
    }

    public String getLoginPassword() {
        return loginPassword;
    }

    public void setLoginPassword(String loginPassword) {
        this.loginPassword = loginPassword;
    }

    public Integer getRole() {
        return role;
    }

    public void setRole(Integer role) {
        this.role = role;
    }

    public Date getCreateTime() {
        return createTime;
    }

    public void setCreateTime(Date createTime) {
        this.createTime = createTime;
    }

    public Date getUpdateTime() {
        return updateTime;
    }

    public void setUpdateTime(Date updateTime) {
        this.updateTime = updateTime;
    }
}

② Page类

package com.allen.entity.ao;

import java.util.List;

public class Page {
    private List list;
    private long count;
    private int pageCount;
    private int page=1;
    private int size=10;

    public List getList() {
        return list;
    }

    public void setList(List list) {
        this.list = list;
    }

    public long getCount() {
        return count;
    }

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

    public int getPageCount() {
        return pageCount;
    }

    public void setPageCount(int pageCount) {
        this.pageCount = pageCount;
    }

    public int getPage() {
        return page;
    }

    public void setPage(int page) {
        this.page = page;
    }

    public int getSize() {
        return size;
    }

    public void setSize(int size) {
        this.size = size;
    }
}

③ UserDao类

package com.allen.dao;

import com.allen.entity.User;

import java.sql.*;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;

public class UserDao {

    
    public List find(int page, int size, String name) throws ClassNotFoundException, SQLException {
        Class.forName("com.mysql.jdbc.Driver");
        Connection connection = DriverManager.getConnection("jdbc:mysql:///user-test?useSSL=false", "root", "123456");
        PreparedStatement statement;
        if (name != null && name != "") {
            statement = connection.prepareStatement("select * from user where true_name like ? limit ?,?");
            statement.setObject(1, "%" + name + "%");
            statement.setObject(2, (page - 1) * size);
            statement.setObject(3, size);
        } else {
            statement = connection.prepareStatement("select * from user limit ?,?");
            statement.setObject(1, (page - 1) * size);
            statement.setObject(2, size);
        }
        ResultSet resultSet = statement.executeQuery();
        List list = new ArrayList<>();
        while (resultSet.next()) {
            User user = new User();
            user.setId(resultSet.getInt("id"));
            user.setTrueName(resultSet.getString("true_name"));
            user.setLoginName(resultSet.getString("login_name"));
            user.setLoginPassword(resultSet.getString("login_password"));
            user.setRole(resultSet.getInt("role"));
            //这里需要使用时间戳，才会显示年月日，时分秒
            user.setCreateTime(resultSet.getTimestamp("create_time"));
            user.setUpdateTime(resultSet.getTimestamp("update_time"));
            list.add(user);
        }
        resultSet.close();
        statement.close();
        connection.close();
        return list;
    }

    
    public long count(String name) throws ClassNotFoundException, SQLException {
        Class.forName("com.mysql.jdbc.Driver");
        Connection connection = DriverManager.getConnection("jdbc:mysql:///user-test?useSSL=false", "root", "123456");
        PreparedStatement statement;
        if (name != null && name != "") {
            statement = connection.prepareStatement("select count(*) from user where true_name like ?");
            statement.setObject(1, "%" + name + "%");
        } else {
            statement = connection.prepareStatement("select count(*) from user");
        }
        ResultSet resultSet = statement.executeQuery();
        long count = 0;
        while (resultSet.next()) {
            count = resultSet.getLong(1);
        }
        resultSet.close();
        statement.close();
        connection.close();
        return count;
    }

    
    public void deleteById(int id) throws ClassNotFoundException, SQLException {
        Class.forName("com.mysql.jdbc.Driver");
        Connection connection = DriverManager.getConnection("jdbc:mysql:///user-test?useSSL=false", "root", "123456");
        PreparedStatement statement = connection.prepareStatement("delete from user where id=?");
        statement.setObject(1, id);
        int i = statement.executeUpdate();
        statement.close();
        connection.close();
    }

    
    public void insert(User user) throws ClassNotFoundException, SQLException {
        Class.forName("com.mysql.jdbc.Driver");
        Connection connection = DriverManager.getConnection("jdbc:mysql:///user-test?useSSL=false", "root", "123456");
        PreparedStatement statement = connection.prepareStatement("insert into user(true_name,login_name,login_password,role,create_time)"+" values (?,?,?,?,now())");
        statement.setObject(1, user.getTrueName());
        statement.setObject(2, user.getLoginName());
        statement.setObject(3, user.getLoginPassword());
        statement.setObject(4, user.getRole());
        int i = statement.executeUpdate();
        statement.close();
        connection.close();
    }

    
    public User findById(int id) throws ClassNotFoundException, SQLException {
        Class.forName("com.mysql.jdbc.Driver");
        Connection connection = DriverManager.getConnection("jdbc:mysql:///user-test?useSSL=false", "root", "123456");
        PreparedStatement statement = connection.prepareStatement("select * from user where id=?");
        statement.setObject(1,id);
        ResultSet resultSet = statement.executeQuery();
        User user=null;
        if (resultSet.next()) {
          user = new User();
          user.setId(id);
          user.setTrueName(resultSet.getString("true_name"));
          user.setLoginName(resultSet.getString("login_name"));
          user.setLoginPassword(resultSet.getString("login_password"));
          user.setRole(resultSet.getInt("role"));
          user.setCreateTime(resultSet.getTimestamp("create_time"));
          user.setUpdateTime(resultSet.getTimestamp("update_time"));
        }
        resultSet.close();
        statement.close();
        connection.close();
        return user;
    }

    
    public void update(User user) throws ClassNotFoundException, SQLException {
        Class.forName("com.mysql.jdbc.Driver");
        Connection connection = DriverManager.getConnection("jdbc:mysql:///user-test?useSSL=false", "root", "123456");
        PreparedStatement statement = connection.prepareStatement("update user set true_name=?,login_name=?,login_password=?,role=?,update_time=now()"+" where id=?");
        statement.setObject(1, user.getTrueName());
        statement.setObject(2, user.getLoginName());
        statement.setObject(3, user.getLoginPassword());
        statement.setObject(4, user.getRole());
        statement.setObject(5, user.getId());
        int i = statement.executeUpdate();
        statement.close();
        connection.close();
    }
}

④ CodeFilter类

package com.allen.filter;

import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

@WebFilter("/*")
public class CodeFilter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {

    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        HttpServletRequest request = (HttpServletRequest) servletRequest;
        HttpServletResponse respons= (HttpServletResponse) servletResponse;
        request.setCharacterEncoding("UTF-8");
        respons.setCharacterEncoding("UTF-8");
        filterChain.doFilter(request,respons);
    }

    @Override
    public void destroy() {

    }
}

⑤ UserService 类

package com.allen.service;

import com.allen.dao.UserDao;
import com.allen.entity.User;
import com.allen.entity.ao.Page;

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

public class UserService {
    UserDao userDao = new UserDao();
    public Page page(Page page, String name) throws SQLException, ClassNotFoundException {
        int size = page.getSize();
        List list = userDao.find(page.getPage(), size, name);
        page.setList(list);
        long count = userDao.count(name);
        page.setCount(count);
        page.setPageCount((int)((count%size==0)?(count/size):((count/size)+1)));
        return page;
    }

    public void delete(int id) throws SQLException, ClassNotFoundException {
        userDao.deleteById(id);
    }

    public void keep(User user) throws SQLException, ClassNotFoundException {
        if(user.getId()!=null){
            userDao.update(user);
        }else{
            userDao.insert(user);
        }
    }

    public User findById(int id) throws SQLException, ClassNotFoundException {
        return userDao.findById(id);
    }
}

⑥ IndexServlet 类

package com.allen.servlet;

import com.allen.entity.User;
import com.allen.entity.ao.Page;
import com.allen.service.UserService;

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;

@WebServlet("/index")
public class IndexServlet extends HttpServlet {
    UserService userService = new UserService();
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        try {
            request.setCharacterEncoding("UTF-8");
            Page pageAo = new Page<>();
            String page = request.getParameter("page");
            if (page!=null && page!="") {
                pageAo.setPage(Integer.parseInt(page));
            }
            String size = request.getParameter("size");
            if (size!=null && size!="") {
                pageAo.setSize(Integer.parseInt(size));
            }
            Page userPage = userService.page(pageAo, request.getParameter("name"));
            request.setAttribute("userPage",userPage);
            request.getRequestDispatcher("/WEB-INF/jsp/index.jsp").forward(request,response);
        }catch (Exception e){
            e.printStackTrace();
        }
    }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

    }
}

⑦ UserDeleteServlet 类

package com.allen.servlet;

import com.allen.service.UserService;

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;
@WebServlet("/userDelete")
public class UserDeleteServlet extends HttpServlet {
    UserService userService = new UserService();
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        try {
            String id = request.getParameter("id");
            if (id!=null && id!="") {
                userService.delete(Integer.parseInt(id));
            }
            response.sendRedirect("index");
        }catch (Exception e){
            e.printStackTrace();
        }
    }
}

⑧ UserEditServlet 类

package com.allen.servlet;

import com.allen.entity.User;
import com.allen.service.UserService;

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;

@WebServlet("/userEdit")
public class UserEditServlet extends HttpServlet {
    private UserService userService = new UserService();
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        try {
            String id = request.getParameter("id");
            if (id!=null && id!="") {
                User user = userService.findById(Integer.parseInt(id));
                request.setAttribute("user",user);
            }
            request.getRequestDispatcher("/WEB-INF/jsp/edit.jsp").forward(request,response);
        }catch(Exception e){
            e.printStackTrace();
        }
    }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        try {
            String loginName = request.getParameter("loginName");
            String loginPassword = request.getParameter("loginPassword");
            String role = request.getParameter("role");
            String trueName = request.getParameter("trueName");
            String id = request.getParameter("id");
            User user = new User();
            user.setLoginName(loginName);
            user.setLoginPassword(loginPassword);
            user.setRole(Integer.parseInt(role));
            user.setTrueName(trueName);
            if (id!=null && id!="") {
                user.setId(Integer.parseInt(id));
            }
            userService.keep(user);
            response.sendRedirect(request.getContextPath()+"/index");
        }catch (Exception e){
            e.printStackTrace();
        }
    }
}

⑨ edit.jsp

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


    Title
    



    
        
            用户编辑
            
                
                    登录名
                    
                        
                    
                
                
                    密码
                    
                        
                    
                
                
                    姓名
                    
                        
                    
                
                
                    角色
                    
                        
                    
                
                
                    
                        
                        取消

⑩ index.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>


    用户管理
    



    
        用户管理
        
            用户添加
        
        
            
                
                class="input-group-addon" onclick="findByName()">搜索
            
        
        
            
                    
                
                
                    ID
                    姓名
                    登录名
                    密码
                    角色
                    创建时间
                    修改时间
                    编辑
                
                
                
                
                        ${u.id}
                        ${u.trueName}
                        ${u.loginName}
                        ${u.loginPassword}
                        ${u.role==1?"超级管理员":u.role==2?"普通用户":u.role==3?"用户管理员":""}
                        ${u.createTime}
                        ${u.updateTime}
                        
                            删除
                            修改
                        
                    
                

                
            
            <%--            ${userPage.pageCount}--%>
<%--            &name=${param.name}信息回显并查询列表--%>
            
                
                    
                        
                            aria-hidden="true">上一页
                        
                    
                    
                        ${u}
                    

                    
                        
                            aria-hidden="true">下一页(${userPage.count})

ID	姓名	登录名	密码	角色	创建时间	修改时间	编辑
${u.id}	${u.trueName}	${u.loginName}	${u.loginPassword}	${u.role==1?"超级管理员":u.role==2?"普通用户":u.role==3?"用户管理员":""}	${u.createTime}	${u.updateTime}	删除修改

⑩① web.xml



    
        index

⑩② pom.xml



    4.0.0

    com.example
    user-test
    1.0-SNAPSHOT
    user-test
    war

    
        1.8
        1.8
        5.7.1
    

    
        
            javax.servlet
            javax.servlet-api
            4.0.1
            provided
        
        
            org.junit.jupiter
            junit-jupiter-api
            ${junit.version}
            test
        
        
            org.junit.jupiter
            junit-jupiter-engine
            ${junit.version}
            test
        
    

    
        
            
                org.apache.maven.plugins
                maven-war-plugin
                3.3.1

三、效果截图

用户添加如下：

用户修改如下：

用户修改成功如下：

数据分页如下：

模糊查询结果如下：

简单的增删改查及数据分页

用户编辑

用户管理

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