【Spring MVC篇】简单案例分析

个人主页：兜里有颗棉花糖
欢迎点赞👍 收藏✨ 留言✉ 加关注💓本文由兜里有颗棉花糖原创
收录于专栏【Spring MVC】
本专栏旨在分享学习Spring MVC的一点学习心得，欢迎大家在评论区交流讨论💌

一、加法计算器

前端代码：

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
     <form action="/calc/sum" method="post">
        <h1>计算器</h1>
        数字1：<input name="num1" type="text"><br>
        数字2：<input name="num2" type="text"><br>
        <input type="submit" value=" 点击相加 ">
    </form>
</body>

</html>

后端代码：

package org.example.demo1.demos.web.controller;

import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RequestMapping("/calc")
@RestController
public class CalcController {
    @RequestMapping("/sum")
    public String sum(Integer num1,Integer num2) {
        Integer sum = num1 + num2;
        return "计算结果为:" + sum;
    }
}

运行结果：

二、登录页面

前端两个文件（login.html、index.html），后端一个文件（UserController.java）。

后端代码如下：

package org.example.demo1.demos.web.controller;

import org.springframework.util.StringUtils;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import javax.servlet.http.HttpSession;

@RequestMapping("/user")
@RestController
public class UserController {
    @RequestMapping("/login")
    public Boolean login(String userName, String password, HttpSession session) {
        // 校验参数的合法性
        if(!StringUtils.hasLength(userName) || !StringUtils.hasLength(password))
            return false;

        // 进行用户名和密码的校验
        if("admin".equals(userName) && "admin".equals(password)) {
            session.setAttribute("username","admin");
            return true;
        }
        return false;
    }

    @RequestMapping("/getUserInfo")
    public String getUserInfo(HttpSession session) {
        // 从session中获取session用户
        String userName = (String) session.getAttribute("username");
        return userName;
    }
}

login.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>登录页面</title>
</head>
<body>
<h1>用户登录</h1>
用户名：<input name="userName" type="text" id="userName"><br>
密码：<input name="password" type="password" id="password"><br>
<input type="button" value="登录" onclick="login()">

<script src="https://cdn.bootcdn.net/ajax/libs/jquery/3.6.4/jquery.min.js"></script>
<script>
    function login() {
        // console.log("登录...")
        $.ajax({
            url: "/user/login",
            type: "post",
            data:{
                "userName": $("#userName").val(),
                "password": $("#password").val()
            },
            success:function(result) {
                if(result) {
                    location.href = "/index.html"; // 方式一
                    // location.assign(); 方式二
                }else {
                    alert("密码错误");
                }
            }
        })
    }
</script>
</body>

</html>

index.html

<!doctype html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport"
          content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>用户登录首页</title>
</head>

<body>
登录人: <span id="loginUser"></span>

<script src="https://cdn.bootcdn.net/ajax/libs/jquery/3.6.4/jquery.min.js"></script>
<script>
    // 页面加载时，就去调用后端请求
    $.ajax({
        url: "/user/getUserInfo",
        type: "get",
        success:function(username) {
            $("#loginUser").text(username);
        }
    })
</script>
</body>
</html>

三、留言板

后端接口定义：
1.提交留言（/message/publish）：
参数：MessageInfo(from,to,message)
返回结果：true/false
2.查看所有留言（/message/getMessageList）：
参数：无
返回结果：List<MessageInfo>

前端代码：

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>留言板</title>
    <style>
        .container {
            width: 350px;
            height: 300px;
            margin: 0 auto;
            /* border: 1px black solid; */
            text-align: center;
        }

        .grey {
            color: grey;
        }

        .container .row {
            width: 350px;
            height: 40px;

            display: flex;
            justify-content: space-between;
            align-items: center;
        }

        .container .row input {
            width: 260px;
            height: 30px;
        }

        #submit {
            width: 350px;
            height: 40px;
            background-color: orange;
            color: white;
            border: none;
            margin: 10px;
            border-radius: 5px;
            font-size: 20px;
        }
    </style>
</head>

<body>
<div class="container">
    <h1>留言板</h1>
    <p class="grey">输入后点击提交, 会将信息显示下方空白处</p>
    <div class="row">
        <span>谁:</span> <input type="text" name="" id="from">
    </div>
    <div class="row">
        <span>对谁:</span> <input type="text" name="" id="to">
    </div>
    <div class="row">
        <span>说什么:</span> <input type="text" name="" id="say">
    </div>
    <input type="button" value="提交" id="submit" onclick="submit()">
    <!-- <div>A 对 B 说: hello</div> -->
</div>

<script src="https://cdn.bootcdn.net/ajax/libs/jquery/3.6.4/jquery.min.js"></script>
<script>
    // 页面加载时请求后端获取留言列表
    $.ajax({
        url: "/message/getMessageInfo",
        type: "get",
        success: function(messages){
            for(var m of messages){
                //2. 构造节点(拼接节点的html)
                var divE = "<div>"+m.from +"对" + m.to + "说:" + m.message+"</div>";
                //3. 把节点添加到页面上
                $(".container").append(divE);
            }
        }
    });
    function submit(){
        //1. 获取留言的内容
        var from = $('#from').val();
        var to = $('#to').val();
        var say = $('#say').val();
        if (from== '' || to == '' || say == '') {
            return;
        }

        // 提交留言
        $.ajax({
            url: "/message/publish",
            type: "post",
            data: {
                "from":from,
                "to":to,
                "message":say
            },
            success:function (result){
                if(result) {
                    // 留言成功
                    //2. 构造节点
                    var divE = "<div>"+from +"对" + to + "说:" + say+"</div>";
                    //3. 把节点添加到页面上
                    $(".container").append(divE);

                    //4. 清空输入框的值
                    $('#from').val("");
                    $('#to').val("");
                    $('#say').val("");
                }else {
                    // 留言失败
                    alert("留言发布失败")
                }
            }
        });


    }
</script>
</body>
</html>

后端代码：

package org.example.demo1.demos.web.controller;


import org.springframework.util.StringUtils;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.ArrayList;
import java.util.List;

@RequestMapping("/message")
@RestController
public class MessageController {
    private List<MessageInfo> messageInfos = new ArrayList<>();
    @RequestMapping("/publish")
    public Boolean publicMessage(MessageInfo messageInfo){
        if(!StringUtils.hasLength(messageInfo.getMessage())
            || !StringUtils.hasLength(messageInfo.getFrom())
            || !StringUtils.hasLength((messageInfo.getTo()))) {
            return false;
        }
        messageInfos.add(messageInfo);
        return true;
    }
    @RequestMapping("/getMessageInfo")
    public List<MessageInfo> getMessageInfo(){
        return messageInfos;
    }
}