JavaWeb备忘录

时间:2022-06-28 陆鳴笙人气:0

所用技术

HTML，CSS，JavaScript，Servlet，Tomcat 8.5.60，Mysql 5.7

数据库表

开发工具

IDEA，MySQL Workbench

功能

1、添加未完成事项
2、完成事项

项目演示截图

前端设计

<!DOCTYPE html>
<html lang="en" >
<head>
  <meta charset="UTF-8">
  <title>To-Do-List设计</title>
  <link rel="stylesheet" href="./style.css" >

</head>
<body>
<section class="container">
  <div class="heading">
    <img class="heading_img" src="girl.svg">
    <h1 class="heading_title">To-Do List</h1>
  </div>
  <form class="form">
    <div>
      <label class="form_label" for="todo">~ Today I want to do ~</label>
      <input class="form_input"
           type="text" 
           id="todo" 
           name="to-do"
           size="30"
           required>
      <button class="button" type="type"><span>Submit</span></button>
    </div>
  </form>
  <div>
    <ul class="toDoList"></ul>
  </div>
</section>

<!-- partial -->
  <script src="./script.js"></script>
</body>
</html>

body {
    background-color: #f7d3c1;
    min-height: 70vh;
    padding: 1rem;
    box-sizing: border-box;
    display: flex;
    justify-content: center;
    align-items: center;
    color: #494a4b;
    font-family: "Gochi Hand", cursive;
    text-align: center;
    font-size: 130%;
}

@media only screen and (min-width: 500px) {
    body {
        min-height: 100vh;
    }
}

.container {
    width: 100%;
    height: auto;
    min-height: 500px;
    max-width: 500px;
    min-width: 250px;
    background: #f1f5f8;
    background-image: radial-gradient(#bfc0c1 7.2%, transparent 0);
    background-size: 25px 25px;
    border-radius: 20px;
    box-shadow: 4px 3px 7px 2px #000000;
    padding: 1rem;
    box-sizing: border-box;
}

.heading {
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 1rem;
}

.heading_title {
    transform: rotate(2deg);
    padding: 0.2rem 1.2rem;
    border-radius: 20% 5% 20% 5%/5% 20% 25% 20%;
    background-color: lightpink;
    font-size: 1.5rem;
}

@media only screen and (min-width: 500px) {
    .heading_title {
        font-size: 2rem;
    }
}

.heading_img {
    width: 24%;
}

.form_label {
    display: block;
    margin-bottom: 0.5rem;
}

.form_input {
    box-sizing: border-box;
    background-color: transparent;
    padding: 0.7rem;
    border-bottom-right-radius: 15px 3px;
    border-bottom-left-radius: 3px 15px;
    border: solid 3px transparent;
    border-bottom: dashed 3px #95a9ea;
    font-family: "Gochi Hand", cursive;
    font-size: 1rem;
    color: rgba(63, 62, 65, 0.7);
    width: 70%;
    margin-bottom: 20px;
}

.form_input:focus {
    outline: none;
    border: solid 3px #95a9ea;
}

@media only screen and (min-width: 500px) {
    .form_input {
        width: 60%;
    }
}

.button {
    padding: 0;
    border: none;
    transform: rotate(4deg);
    transform-origin: center;
    font-family: "Gochi Hand", cursive;
    text-decoration: none;
    padding-bottom: 3px;
    border-radius: 5px;
    box-shadow: 0 2px 0 #494a4b;
    transition: all 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    background-image: url("data:image/gif;base64,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");
    background-color: rgba(0, 119, 255, 0.7);
}

.button span {
    background: #f1f5f8;
    display: block;
    padding: 0.5rem 1rem;
    border-radius: 5px;
    border: 2px solid #494a4b;
}

.button:active, .button:focus {
    transform: translateY(4px);
    padding-bottom: 0px;
    outline: 0;
}

.toDoList {
    text-align: left;
}

.toDoList li {
    position: relative;
    padding: 0.5rem;
}

.finish{
    text-decoration: line-through wavy #fb8524b6;
}
.toDoList li:hover {
    text-decoration: line-through wavy #fb8524b6;
}

var htmlRoot = document.querySelector("html");
var ulTodoList = document.querySelector("ul.toDoList");
var input = document.querySelector("input#todo");

function finishTodoItem() {
    //this 就是触发事件的元素（就是用户点击的元素）
    var id = this.dataset.id;
    var url = "/finish?id=" + id;
    var xhr = new XMLHttpRequest();
    var self = this;
    xhr.open("get",url);
    xhr.send();
    xhr.onload = function () {
        self.classList.add("finish");
        self.onclick = null;
    }
}

function appendTodo(todo) {
    var todoLi = document.createElement("li");
    todoLi.innerText = todo.todo;
    if(todo.state == true){
        todoLi.classList.add("finish");
    }else{
        todoLi.onclick = finishTodoItem;
        todoLi.dataset.id = todo.id;
    }
    ulTodoList.appendChild(todoLi);
}

//为"submit"按钮绑定save函数
function save() {
    var todoInput = input.value;
    var url = "/save?todo=" + encodeURI(todoInput);
    var xhr = new XMLHttpRequest();
    function success() {
        var todo = {
            "id":parseInt(xhr.responseText),
            "todo":todoInput,
            "state":0,
        };

        appendTodo(todo);
    }
    xhr.onload = success;
    xhr.open("get",url);
    xhr.send();
}
var submitBtn = document.querySelector(".button");
submitBtn.onclick =  save;

//页面加载完成之后，请求列表资源
function LoadTodoList() {
    var xhr = new XMLHttpRequest();
    function success() {
        if (xhr.status != 200){
            htmlRoot.innerHTML = xhr.responseText;
            return;
        }

        //1、JS进行JSON的反序列化
        var todoList = JSON.parse(xhr.responseText);
        //遍历每一项，添加到DOM树中
        for (var todo of todoList){
            appendTodo(todo);
        }
    }
    xhr.onload = success;
    xhr.open("get","/list");
    xhr.send();
}
LoadTodoList();

后端设计

@WebServlet("/finish")
public class FinishServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //1、获取用户点击事项的id
        req.setCharacterEncoding("utf-8");
        String id = req.getParameter("id");
        //进行数据库表的更新
        try (Connection c = DBUtil.connection()) {
            String sql = "UPDATE item set state = 1 WHERE id=?";
            try (PreparedStatement s = c.prepareStatement(sql)) {
                s.setString(1, id);

                s.executeUpdate();
            }
        } catch (SQLException exc) {
            throw new ServletException(exc);
        }
    }
}

@WebServlet("/list")
public class ListServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //1、从数据库中查出List<待办事项>todolist
        List<TodoItem> todolist = new ArrayList<>();
        try (Connection c = DBUtil.connection()){
            String sql = "SELECT id,todo,state FROM item ORDER BY id";
            try(PreparedStatement s = c.prepareStatement(sql)){
                try (ResultSet rs = s.executeQuery()){
                    while(rs.next()){
                        TodoItem todo = new TodoItem();
                        todo.id = rs.getInt("id");
                        todo.todo = rs.getString("todo");
                        todo.state = rs.getBoolean("state");

                        todolist.add(todo);
                    }
                }
            }
        } catch (SQLException exc) {
            throw new ServletException(exc);
        }

        //2、把todolist序列化成JSON格式的字符串
        ObjectMapper objectMapper = new ObjectMapper();
        String s = objectMapper.writeValueAsString(todolist);
        //3、进行响应输出
        resp.setCharacterEncoding("utf-8");
        resp.setContentType("application/json");
        resp.getWriter().println(s);

    }
}

@WebServlet("/save")
public class SaveServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //1、读取用户填写的内容
        req.setCharacterEncoding("utf-8");
        String todo = req.getParameter("todo");
        //2、执行SQL,把内容写入表中
        int id;
        try (Connection c = DBUtil.connection()){
            String sql = "INSERT INTO item(todo)VALUES(?)";
            try (PreparedStatement s = c.prepareStatement(sql,Statement.RETURN_GENERATED_KEYS)){
                s.setString(1,todo);

                s.executeUpdate();

                try(ResultSet rs = s.getGeneratedKeys()){
                    rs.next();
                    id = rs.getInt(1);
                }
            }
        } catch (SQLException exc) {
            throw new ServletException(exc);
        }
        //3、手动写一个JSON成功
        resp.setCharacterEncoding("utf-8");
        resp.setContentType("application/json");
        resp.getWriter().println(id);
    }
}

public class TodoItem {
    public Integer id;
    public String todo;
    public boolean state;
}

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