制作留言板

1.用session存取数据

(1)MessageController


package com.example.message.controller;

import com.example.message.entity.Message;
import com.example.message.util.Result;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import javax.servlet.http.HttpServletRequest;
import java.util.ArrayList;
import java.util.List;

@RestController
@RequestMapping("/message")
public class MessageController {
    @PostMapping("/insert")
    public Result insert(Message message, HttpServletRequest request){
        List<Message> messageList = (List<Message>)request.getSession().getAttribute("list");
        if(messageList == null){
            messageList = new ArrayList<>();
        }
        messageList.add(message);
        request.getSession().setAttribute("list",messageList);
        System.out.println(message);
        return Result.success();
    }
    @GetMapping("/getAll")
    public Result getAll(HttpServletRequest request){
        List<Message> messageList = (List<Message>)request.getSession().getAttribute("list");
        return Result.success(messageList);
    }
}

(2)Message实体

package com.example.message.entity;

import lombok.Data;

@Data
public class Message {
    private String author;
    private String content;
    private String date;
}

(3)工具类Result


import com.fasterxml.jackson.annotation.JsonInclude;
import lombok.Data;

@Data
@JsonInclude(JsonInclude.Include.NON_NULL)
public class Result<T> {
    private Integer code;
    private String message;
    private Object data;

    public Result() {
        this.code = 200;
        this.message = "操作成功";
    }

    /**
     * 用于@valid错误处理
     *
     * @param code    错误码
     * @param message 错误提示信息
     */
    public Result(Integer code, String message) {
        this.code = code;
        this.message = message;
    }

    /**
     * 用于封装返回数据
     *
     * @param code    返回码
     * @param message 提示信息
     */
    public Result(Integer code, String message, Object data) {
        this.code = code;
        this.message = message;
        this.data = data;
    }

    //系统错误
    public static Result<String> error(String message) {
        return new Result<>(400, message);
    }

    //操作成功，返回数据
    public static Result<Object> success(Object data) {
        return new Result<>(200, "success", data);
    }

    //操作成功，无返回数据
    public static Result<Object> success() {
        return new Result<>(200, "success");
    }

    //操作失败，返回数据
    public static Result<Object> fail(Object data) {
        return new Result<>(200, "fail", data);
    }

    //操作失败，无返回数据
    public static Result<Object> fail() {
        return new Result<>(200, "fail");
    }
}

(4)静态页

<!DOCTYPE html>
<html lang="en">
<head>
    <title>留言板</title>
    <meta charset="UTF-8">
    <style>
        div {
            margin: 0;
            padding: 0;
            font-size: 12px;
            margin: 0 auto;
        }

        h3 {
            text-align: center
        }

        #container {
            width: 500px;
        }

        .article {
            border: 1px solid #a6cbe7;
            margin-top: 5px;
        }

        .author {
            background-color: #0099FF;
            width: 100%;
            height: 24px;
            line-height: 24px;
        }

        .content {
            height: 40px;
            padding: 10px;
        }

        .author span {
            float: right;
            padding-right: 10px;
        }

        .time {
            border-top: solid 1px #a6cbe7;
        }

        .page {
            text-align: right;
            height: 30px;
            line-height: 30px;
            padding-right: 10px;
        }
    </style>
    <script src="js/jquery-3.5.1.js"></script>
    <script src="js/vue.js"></script>
    <script>
        function todate(num) {
            if(num<10) return '0'+ num;
            else return num;
        }
        $(function (){
            //1、获得数据
            $.getJSON("/message/getAll",function (result){
                vm.msgs = result.data;
            });
            //2、展示数据
            let vm = new Vue({
                el:"#container",
                data:{
                    msgs : [],
                }
            });
            $("#publish").click(function(){
                var dateobject = new Date();
                var year = dateobject.getFullYear();
                var month = todate(dateobject.getMonth()+1);
                var date = todate(dateobject.getDate());
                var hour = todate(dateobject.getHours());
                var minute = todate(dateobject.getMinutes());
                var second =todate(dateobject.getSeconds());
                var dateTime = year + "年" + month + "月" + date + "日" +hour + "：" + minute + "：" + second;
                // console.log(dateTime);
                $.ajax({
                    //请求地址
                    url : "/message/insert",
                    //请求方式
                    type : "post",
                    //提交数据 json字符串
                    data : {author: $("input:text").val(),content:$("textarea").val(),date:dateTime},
                    //
                    //返回值类型
                    dataType : "json",
                    //请求成功
                    success : function(result) {
                        console.log(result);
                        console.log(result.message);
                    }
                })
                 window.location.reload();
            });
        });
    </script>
</head>

<body>
<div id="container">
    <div><h3>留言板</h3></div>
    <div>
        <div class="article" v-for="msg in msgs" >
            <div class="author">用户:{{msg.author}}<span id="addFloor">1#</span></div>
            <div class="content">{{msg.content}}</div>
            <div class="time page">发表于：{{msg.date}}</div>
        </div>
    </div>

    <div class="page">
        <input class="btn1" type="button" value="上一页" onClick="">
        <input class="btn2" type="button" value="下一页" onClick="">
    </div><br>
    <div>
        <form>
            <div>
                用户: <input type="text" name="author" value=""/>
            </div><br>
            <div>
                留言: <textarea name="message" rows="5" cols="72"></textarea>
            </div>
            <div align="center"><input type="reset" value="清除"/> <input type="button" value="发表" id="publish"/></div>
        </form>
        </br>
        </br>
        </br>


    </div>
</div>
</body>
</html>

(5)效果图

(6)存在的问题每次都会创建一个session，无法使楼层自增，所以用数据库来存取数据

2.用mysql数据库

(1)连接数据库并配置application.properties文件，修改后缀为yml

#连接池配置
spring:
  datasource:
    driver-class-name: com.mysql.cj.jdbc.Driver
    username: root
    password: 990731
    url: jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=utf8
#日期格式
jackson:
    date-format: yyyy-MM-dd HH:mm:ss
    time-zone: GMT+8
#mybatis配置
mybatis:
  configuration:
    map-underscore-to-camel-case: true
#showSql
logging:
  level:
    org.lanqiao.book21.dao: debug

（2）添加依赖

<dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.1.1</version>
  </dependency>

(3)MessageDao

package com.example.message.dao;
import com.example.message.entity.Message;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Select;

import java.util.List;

@Mapper
public interface MessageDao {
   @Insert("insert into message(author,content,date) values(#{author},#{content},#{date})")
 //将数据库中的id回调
  @Options(useGeneratedKeys = true,keyColumn="id")

   public void insert(Message message);
   @Select("select * from message")
   public List<Message> getAll();
}

(4)MessageService

package com.example.message.service;

import com.example.message.entity.Message;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Select;

import java.util.List;

public interface MessageService {
    public void insert(Message message);
    public List<Message> getAll();
}

(5)MessageServiceImpl

package com.example.message.service.impl;

import com.example.message.dao.MessageDao;
import com.example.message.entity.Message;
import com.example.message.service.MessageService;
import org.springframework.beans.factory.annotation.Autowired;

import java.util.List;
@Service
public class MessageServiceImpl implements MessageService {
    @Autowired
    MessageDao messageDao;
    @Override
    public void insert(Message message) {
       message.setDate(new Date());
        messageDao.insert(message);
    }

    @Override
    public List<Message> getAll() {
        return messageDao.getAll();
    }
}

(6)MessageController

package com.example.message.controller;

import com.example.message.entity.Message;
import com.example.message.service.MessageService;
import com.example.message.util.Result;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import javax.servlet.http.HttpServletRequest;
import java.util.ArrayList;
import java.util.List;

@RestController
@RequestMapping("/message")
public class MessageController {
    @Autowired
    MessageService messageService;
    @PostMapping("/insert")
    public Result insert(Message message){
       messageService.insert(message);
        return Result.success(message);
    }
    @GetMapping("/getAll")
    public Result getAll(){
        return Result.success(messageService.getAll());
    }
}

3.增加翻页功能

（1）增加依赖

<dependency>
        <groupId>com.github.pagehelper</groupId>
        <artifactId>pagehelper-spring-boot-starter</artifactId>
        <scope>1.2.13</scope>
        </dependency>

(2)修改MessageController.java里的getAll方法

@GetMapping("/getAll")
    public Result getAll(int pageNum,int pageSize){
        PageHelper.startPage(pageNum,pageSize);
        List<Message> messageList = messageService.getAll();
        PageInfo<Message> pageInfo = new PageInfo<>(messageList);
        return Result.success(pageInfo);

（3）修改html

   $(function (){
            const pageSize =5;
            let nextPage;
            let prePage;
            //获得数据
            function getPage(num,size){
                $.getJSON("/message/getAll",{pageNum:num,pageSize:size},function (result){
                    vm.msgs = result.data.list;
                    nextPage = result.data.nextPage;
                    prePage = result.data.prePage;
                });
            }
            //第一页
            getPage(1,pageSize);
            //展示数据
            let vm = new Vue({
                el:"#container",
                data:{
                    msgs : [],
                }
            });
            $("#publish").click(function(){
                $.ajax({
                    //请求地址
                    url : "/message/insert",
                    //请求方式
                    type : "post",
                    //提交数据 json字符串
                    data : {author: $("input:text").val(),content:$("textarea").val()},
                    //
                    //返回值类型
                    dataType : "json",
                    //请求成功
                    success : function(result) {
                       vm.msgs.push(result.data);
                        $("input:text").val("");
                        $("textarea").val();
                    }
                })
            });
            $(".btn1").click(function(){
                if(prePage!=0) getPage(prePage,pageSize);
                else alert("已经是第一页");
               });
            $(".btn2").click(function(){
                if(nextPage!=0) getPage(nextPage,pageSize);
                else alert("已经是最后一页");
            });
        });

4动态查找

（1）修改MessageDao

@Select("<script>select * from message"+
           "<where>"+
           "<if test=\"author!=null and author!=''\">"+
                "author=#{author}"+
            "</if>"+
           "<if test=\"content!=null and content!=''\">"+
           "and content like '%' #{content} '%'"+
           "</if>"+
           "</where>"+
           "</script>")
   public List<Message> getBySearch(Message message);

(2)修改MessageService

public List<Message> getBySearch(Message message);

(3)修改MessageServiceImp

@Override
    public List<Message> getBySearch(Message message) {
        return messageDao.getBySearch(message);
    }

(4)修改MessageController

@PostMapping("/getBySearch")
    public Result getBySearch(Message message,int pageNum,int pageSize){
        PageHelper.startPage(pageNum,pageSize);
        List<Message> messageList = messageService.getBySearch(message);
        PageInfo<Message> pageInfo = new PageInfo<>(messageList);
        return Result.success(pageInfo);
    }

(5)html

<script>
        $(function (){
            let size =2;
            let num =1;
            let nextPage;
            let prePage;
            let url = "/message/getAll";
            let obj = {pageNum:num,pageSize:size}
            //获得数据
            function getPage(url,obj){
                $.post(url,obj,function (result){
                    vm.msgs = result.data.list;
                    nextPage = result.data.nextPage;
                    prePage = result.data.prePage;
                },"json");
            }
            //第一页
            getPage(url,obj);
            //展示数据
            let vm = new Vue({
                el:"#container",
                data:{
                    msgs : [],
                }
            });
            $("#publish").click(function(){
                $.ajax({
                    //请求地址
                    url : "/message/insert",
                    //请求方式
                    type : "post",
                    //提交数据 json字符串
                    data : {author: $(".author").val(),content:$("textarea").val()},
                    //
                    //返回值类型
                    dataType : "json",
                    //请求成功
                    success : function(result) {
                       vm.msgs.push(result.data);
                        $("input:text").val("");
                        $("textarea").val();
                    }
                })
            });
            $("#search").click(function(){
                url = "/message/getBySearch";
                obj = {author:$("input[name=author]").val(),content:$("input[name=content]").val(),pageNum:num,pageSize:size};
                getPage(url,obj);
            });
            $(".btn1").click(function(){
                if(prePage!=0) {
                    obj.pageNum = prePage;
                    getPage(url, obj);
                }
                else {
                    {
                        alert("已经是第一页");
                    }
                }
               });
            $(".btn2").click(function(){
                if(nextPage!=0) {
                    obj.pageNum = nextPage;
                    getPage(url, obj);
                }
                else {
                    {
                        alert("已经是最后一页");
                    }
                }
            });
        });
    </script>
</head>

<body>
<div id="container">
    <div><h3>留言板</h3></div>
    <div>
        用户：<input type="text" name="author"> 留言：<input type="text" name="content">
        <input id="search" type="button" value="搜索">
        <div class="article" v-for="msg in msgs" >
            <div class="author">用户:{{msg.author}}<span id="addFloor">{{msg.id}}</span></div>
            <div class="content">{{msg.content}}</div>
            <div class="time page">"发表于："{{msg.date}}</div>
        </div>
    </div>

    <div class="page">
        <input class="btn1" type="button" value="上一页" onClick="">
        <input class="btn2" type="button" value="下一页" onClick="">
    </div><br>
    <div>
        <form>
            <div>
                用户: <input type="text" name="author" value=""/>
            </div><br>
            <div>
                留言: <textarea name="message" rows="5" cols="72"></textarea>
            </div>
            <div align="center"><input type="reset" value="清除"/> <input type="button" value="发表" id="publish"/></div>
        </form>
        </br>
        </br>
        </br>


    </div>
</div>
</body>

posted @ 2021-03-17 20:57 0x3fffffff 阅读(321) 评论(0) 编辑收藏举报

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制作留言板

1.用session存取数据

(1)MessageController

(2)Message实体

(3)工具类Result

(4)静态页

(5)效果图

(6)存在的问题 每次都会创建一个session，无法使楼层自增，所以用数据库来存取数据

2.用mysql数据库

(1)连接数据库并配置application.properties文件，修改后缀为yml

（2）添加依赖

(3)MessageDao

(4)MessageService

(5)MessageServiceImpl

(6)MessageController

3.增加翻页功能

（1）增加依赖

(2)修改MessageController.java里的getAll方法

（3）修改html

4动态查找

（1）修改MessageDao

(2)修改MessageService

(3)修改MessageServiceImp

(4)修改MessageController

(5)html

公告

(6)存在的问题每次都会创建一个session，无法使楼层自增，所以用数据库来存取数据