SpringBoot-----从前端更新数据到MySql数据库

dulu~dulu2023-11-19 6:02

目录

（一）连接MySql

（二）创建实体模型

（三）创建Repository接口

（四）创建Controller类

(五)运行AccessingDataMysqlApplication

（六）HTML页面设置

参考SpringBoot官网教程：

1.Validating Form Input

2.Handling Form Submission

3.Accessing data with MySQL

（一）连接MySql

在pom.xml中引入以下依赖：

复制代码 
---------连接数据库----------		
<dependency>
	<groupId>mysql</groupId>
	<artifactId>mysql-connector-java</artifactId>
	<version>8.0.12</version>
</dependency>


-------用于启用JPA和Hibernate,实现数据的持久化-------
	<dependency>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-data-jpa</artifactId>
	</dependency>


-----------启用web应用程序----------
	<dependency>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-web</artifactId>
	</dependency>


--------用于构建交互的WEB应用程序-------
	<dependency>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-thymeleaf</artifactId>
	</dependency>


-------启用校验功能----------
	<dependency>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-validation</artifactId>
		<version>3.1.5</version>
	</dependency>

在application.properties中添加如下代码，连接数据库

复制代码 
spring.jpa.hibernate.ddl-auto=update
spring.datasource.url=jdbc:mysql://localhost:3306/db_example?useSSL=false&serverTimezone=GMT%2B8&useUnicode=true&characterEncoding=UTF-8
spring.datasource.username=root
spring.datasource.password=123456ab
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
#spring.jpa.show-sql: true
# spring.thymeleaf.cache=false
# spring.thymeleaf.prefix=classpath:/templates/
# spring.thymeleaf.suffix=.html

也可以添加application.yml：

application.yml 的功能和 application.properties 是一样的，不过因为yml文件是树状结构，写起来有更好的层次感，更易于理解，所以很多人都选择了yml文件。

复制代码 
spring:
    datasource:
        driver-class-name: com.mysql.jdbc.Driver
        url: jdbc:mysql://localhost:3306/springboot?useUnicode=true&characterEncoding=utf-8&useSSL=false
        username: root
        password: 123456ab
（二）创建实体模型

@Entity注解用于将一个类标识为 JPA 实体，它告诉 Hibernate 或其他 JPA 实现框架将这个类映射为数据库中的表

注：想深入学习校验方法及注释的小伙伴可以看看这个：

如何在 Spring/Spring Boot 中优雅地做参数校验？-腾讯云开发者社区-腾讯云 (tencent.com)

复制代码 
package com.example.accessingdatamysql;

import jakarta.persistence.Entity;
import jakarta.persistence.GeneratedValue;
import jakarta.persistence.GenerationType;
import jakarta.persistence.Id;
import jakarta.persistence.SequenceGenerator;
import jakarta.validation.constraints.NotEmpty;
import jakarta.validation.constraints.Email;
import jakarta.validation.constraints.NotNull;
import jakarta.validation.constraints.Size;

@Entity // This tells Hibernate to make a table out of this class
public class User {
	@Id
//指定序列生成器，序列生成器的名称为"user_seq"
	@GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "user_seq")
//每次增长值为1
	@SequenceGenerator(name = "user_seq", sequenceName = "user_seq", allocationSize = 1)
	private Integer id;

	@NotNull(message = "姓名不能为空")
	@Size(min = 2, max = 30, message = "姓名长度必须在2-30之间")
	private String name;

	@Email
	@NotEmpty(message = "邮箱不能为空")
	private String email;

	public Integer getId() {
		return id;
	}

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

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public String getEmail() {
		return email;
	}

	public void setEmail(String email) {
		this.email = email;
	}

	public String toString() {
		return "User(id:" + this.id + ",name:" + this.name + ",email:" + this.email + ")";
	}
}
（三）创建Repository接口

Repository接口，用于定义数据访问的方法

复制代码 
package com.example.accessingdatamysql;

import org.springframework.data.repository.CrudRepository;

// import com.example.accessingdatamysql.User;

// This will be AUTO IMPLEMENTED by Spring into a Bean called userRepository
// CRUD refers Create, Read, Update, Delete

//使用Iterable，可以根据条件来查询匹配的用户，并获取到一个包含所有符合条件的迭代的用户列表。
public interface UserRepository extends CrudRepository<User, Integer> {

//根据姓名查询用户
    Iterable<User> findByName(String name);

//根据邮箱查询用户
    Iterable<User> findByEmail(String email);

//根据邮箱和姓名查询用户
    Iterable<User> findByNameAndEmail(String email,String name);

}
（四）创建Controller类

Controller类通常用于Web应用程序，它接收用户的HTTP请求，调用业务逻辑处理请求，并返回一个包含响应数据的视图。

复制代码 
package com.example.accessingdatamysql;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.validation.BindingResult;
import org.springframework.validation.annotation.Validated;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.servlet.config.annotation.ViewControllerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

import jakarta.validation.Valid;

@Controller
@Validated
public class WebController implements WebMvcConfigurer {
    @Autowired
    private UserRepository userRepository;

    @Override
    public void addViewControllers(ViewControllerRegistry registry) {
        registry.addViewController("/results").setViewName("results");
    }

    @GetMapping("/form")
    public String showForm(Model model) {
        model.addAttribute("user", new User());
        return "form";
    }

    @PostMapping("/")
    public String submintForm(@Valid @ModelAttribute("user") User user, BindingResult bindingResult) {
        if (bindingResult.hasErrors()) {
            return "form";
        }
        userRepository.save(user);
        return "redirect:/list";
    }

    @GetMapping("/list")
    public String showList(Model model) {
        model.addAttribute("userList", userRepository.findAll());
        return "list";
    }

    @GetMapping(path = "/deleteAll")
    public String deleteAllUsers(Model model) {
        userRepository.deleteAll();
        Iterable<User> userList = userRepository.findAll();
        model.addAttribute("userList", userList);
        return "redirect:/list";
    }

    @GetMapping(path = "/delete/{id}")
    public String deleteUser(@PathVariable("id") Integer id, Model model) {
        userRepository.deleteById(id);
        Iterable<User> userList = userRepository.findAll();
        model.addAttribute("userList", userList);
        return "redirect:/list"; // 返回list.html模板
    }

    @GetMapping(path = "/edit/{id}")
    public String updateUser(@PathVariable("id") Integer id, Model model) {
        User user = userRepository.findById(id).orElseThrow(() -> new IllegalArgumentException("Invalid user ID"));
        model.addAttribute("user", user);
        return "edit";
    }

    @PostMapping(path = "/update")
    public String update(@Valid User user, Model model) {
        userRepository.save(user);
        Iterable<User> userList = userRepository.findAll();
        model.addAttribute("userList", userList);
        return "list";
    }

    @GetMapping("/find")
    public String findUserByNameAndEmail(@RequestParam("name") String name,
            @RequestParam("email") String email, Model model) {
        Iterable<User> userlist;

        if (!name.isEmpty() && !email.isEmpty()) {
            // 根据姓名和邮箱查询用户
            userlist = userRepository.findByNameAndEmail(name, email);
        } else if (!name.isEmpty()) {
            // 根据姓名查询用户
            userlist = userRepository.findByName(name);
        } else if (!email.isEmpty()) {
            // 根据邮箱查询用户
            userlist = userRepository.findByEmail(email);
        } else {
            // 返回所有用户
            userlist = userRepository.findAll();
        }
        model.addAttribute("userlist", userlist);
        return "check";
    }
}

这里的注释

@Valid：用于验证注释是否符合要求，例如

这里就是检验密码是否为空

复制代码 
@RestController
@RequestMapping("/user")
public class UserController {
    @PostMapping
    public User create (@Valid @RequestBody User user) {
        System.out.println(user.getId());
        System.out.println(user.getUsername());
        System.out.println(user.getPassword());
        user.setId("1");
        return user;
    }
}    

public class User {
    private String id;  
 
    @NotBlank(message = "密码不能为空")
    private String password;
}

**@RequestParam：**将请求参数绑定到你控制器的方法参数上（是springmvc中接收普通参数的注解）

复制代码 
//url参数中的name必须要和@RequestParam("name")一致
    @RequestMapping("show16")
    public ModelAndView test16(@RequestParam("name")String name){
        ModelAndView mv = new ModelAndView();
        mv.setViewName("hello");
        mv.addObject("msg", "接收普通的请求参数：" + name);
        return mv;
    }

得到结果

url:localhost:8080/hello/show16?name=cc

页面：

接收普通的请求参数：cc

(五)运行AccessingDataMysqlApplication
复制代码 
package com.example.accessingdatamysql;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class AccessingDataMysqlApplication {

	public static void main(String[] args) {
		SpringApplication.run(AccessingDataMysqlApplication.class, args);
	}
}
（六）HTML页面设置

check.html

复制代码 
<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">

<head>
    <meta charset="UTF-8">
    <title>Check User List</title>
    <style>
        body {
            display: flex;
            align-items: stretch;
            height: 100vh;
            background-color: #f2f2f2;
            justify-content: space-between;
            flex-wrap: wrap;
            flex-direction: column;
            align-content: center;
        }

        table {
            width: 600px;
            margin-top: 20px;
            border-collapse: collapse;
            background-color: #fff;
            box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
        }

        table th,
        table td {
            padding: 10px;
            text-align: center;
            border: 1px solid #ccc;
        }

        table th {
            background-color: #f2f2f2;
        }

        a {
            display: block;
            text-align: center;
            margin-top: 20px;
            text-decoration: none;
            color: #4CAF50;
            font-weight: bold;
        }

        a:hover {
            color: #45a049;
        }

        .btn-edit,
        .btn-delete {
            display: inline-block;
            padding: 5px 10px;
            border: none;
            background-color: #4CAF50;
            color: white;
            text-decoration: none;
            cursor: pointer;
        }

        .btn-edit:hover,
        .btn-delete:hover {
            background-color: #45a049;
        }
    </style>
</head>

<body>
    <h1 style="text-align: center; margin-bottom: 20px;">Check User List</h1>
    <form th:action="@{/find}" method="get" style="text-align: center;">
        <input type="text" name="name" placeholder="姓名">
        <input type="text" name="email" placeholder="邮箱">
        <button type="submit">查询</button>
    </form>
    <table>
        <tr>
            <th>Name</th>
            <th>Email</th>
            <th>操作</th>
        </tr>
        <tr th:each="user : ${userlist}">
            <td th:text="${user.name}"></td>
            <td th:text="${user.email}"></td>
            <td>
                <a th:href="@{'/edit/' + ${user.id}}" class="btn-edit">编辑</a>
                <a th:href="@{'/delete/' + ${user.id}}" class="btn-delete">删除</a>
            </td>
        </tr>
    </table>
    <a href="/form" style="text-align: center; margin-top: 20px; display: block;">添加新信息</a>
</body>

</html>

edit.html

复制代码 
<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">

<head>
    <meta charset="UTF-8">
    <title>Edit User</title>
    <style>
        body {
            display: flex;
            align-items: center;
            height: 100vh;
            background-color: #f2f2f2;
            flex-direction: column;
            flex-wrap: wrap;
            align-content: center;
            justify-content: center;
        }

        form {
            width: 400px;
            padding: 20px;
            background-color: #fff;
            box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
            text-align: center;
        }

        label {
            display: block;
            margin-bottom: 10px;
            font-weight: bold;
        }

        input {
            width: 100%;
            padding: 8px;
            margin-bottom: 20px;
            border: 1px solid #ccc;
            border-radius: 4px;
            box-sizing: border-box;
        }

        button {
            padding: 10px 20px;
            border: none;
            background-color: #4CAF50;
            color: white;
            text-decoration: none;
            cursor: pointer;
        }

        button:hover {
            background-color: #45a049;
        }

        a {
            display: block;
            margin-top: 20px;
            text-align: center;
            text-decoration: none;
            color: #4CAF50;
            font-weight: bold;
        }

        a:hover {
            color: #45a049;
        }
    </style>
</head>

<body>
    <h1>编辑信息</h1>

    <form th:action="@{/update}" method="post">
        <input type="hidden" th:name="id" th:value="${id}" />

        <label for="name">Name:</label>
        <input type="text" id="name" name="name" th:value="${name}" />

        <label for="email">Email:</label>
        <input type="email" id="email" name="email" th:value="${email}" />

        <button type="submit">保存</button>
    </form>

    <a href="/list">返回列表</a>
</body>

</html>

form.html

复制代码 
<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">

<head>
    <meta charset="UTF-8">
    <title>Form</title>
    <style>
        body {
            display: flex;
            justify-content: center;
            align-items: center;
            height: 100vh;
            background-color: #f2f2f2;
        }

        .form-container {
            width: 400px;
            padding: 20px;
            background-color: #fff;
            border-radius: 5px;
            box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
        }

        .form-container h1 {
            text-align: center;
            margin-bottom: 20px;
        }

        .form-container label {
            display: block;
            margin-bottom: 10px;
        }

        .form-container input[type="text"],
        .form-container input[type="email"] {
            width: 100%;
            padding: 10px;
            border: 1px solid #ccc;
            border-radius: 5px;
        }

        .form-container button[type="submit"] {
            display: block;
            width: 100%;
            padding: 10px;
            margin-top: 20px;
            background-color: #4CAF50;
            color: #fff;
            border: none;
            border-radius: 5px;
            cursor: pointer;
        }

        .form-container button[type="submit"]:hover {
            background-color: #45a049;
        }

        .form-container button[type="reset"] {
            display: block;
            width: 100%;
            padding: 10px;
            margin-top: 20px;
            background-color: #4CAF50;
            color: #fff;
            border: none;
            border-radius: 5px;
            cursor: pointer;
        }

        .form-container button[type="reset"]:hover {
            background-color: #45a049;
        }

        .form-container button[type="delete"] {
            display: block;
            width: 100%;
            padding: 10px;
            margin-top: 20px;
            background-color: #4CAF50;
            color: #fff;
            border: none;
            border-radius: 5px;
            cursor: pointer;
        }

        .form-container button[type="delete"]:hover {
            background-color: #45a049;
        }

        .form-container span {
            color: red;
            font-size: 12px;
            margin-top: 5px;
        }
    </style>
</head>


<body>
    <div class="form-container">
        <h1>表格</h1>
        <form action="#" th:action="@{/}" th:object="${user}" method="post">
            <div>
                <label for="name">Name:</label>
                <input type="text" id="name" th:field="*{name}" required>
                <span th:if="${#fields.hasErrors('name')}" th:errors="*{name}">Name Error</span>
            </div>
            <div>
                <label for="email">Email:</label>
                <input type="text" id="email" th:field="*{email}" required>
                <span th:if="${#fields.hasErrors('email')}" th:errors="*{email}">Email Error</span>
            </div>
            <div>
                <button type="submit">Submit</button>
                <button type="reset">Reset</button>
                <button type="delete">Delete</button>
            </div>
        </form>
    </div>
</body>

</html>

list.html

复制代码 
<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">

<head>
    <meta charset="UTF-8">
    <title>List</title>
    <style>
        body {
            display: flex;
            align-items: stretch;
            height: 100vh;
            background-color: #f2f2f2;
            justify-content: space-between;
            flex-wrap: wrap;
            flex-direction: column;
            align-content: center;
        }

        table {
            width: 600px;
            margin-top: 20px;
            border-collapse: collapse;
            background-color: #fff;
            box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
        }

        table th,
        table td {
            padding: 10px;
            text-align: center;
            border: 1px solid #ccc;
        }

        table th {
            background-color: #f2f2f2;
        }

        a {
            display: block;
            text-align: center;
            margin-top: 20px;
            text-decoration: none;
            color: #4CAF50;
            font-weight: bold;
        }

        a:hover {
            color: #45a049;
        }

        .btn-edit,
        .btn-delete {
            display: inline-block;
            padding: 5px 10px;
            border: none;
            background-color: #4CAF50;
            color: white;
            text-decoration: none;
            cursor: pointer;
        }

        .btn-edit:hover,
        .btn-delete:hover {
            background-color: #45a049;
        }

        .btn-delete-all {
            display: block;
            text-align: center;
            margin-top: 20px;
            text-decoration: none;
            color: #f44336;
            font-weight: bold;
        }

        .btn-delete-all:hover {
            color: #d32f2f;
        }
    </style>
</head>

<body>
    <h1 style="text-align: center; margin-bottom: 20px;">信息系统</h1>
    <form th:action="@{/find}" method="get" style="text-align: center;">
        <input type="text" name="name" placeholder="姓名">
        <input type="text" name="email" placeholder="邮箱">
        <button type="submit">查询</button>
    </form>
    <table>
        <tr>
            <th>Name</th>
            <th>Email</th>
            <th>操作</th>
        </tr>
        <tr th:each="user : ${userList}">
            <td th:text="${user.name}"></td>
            <td th:text="${user.email}"></td>
            <td>
                <a th:href="@{'/edit/' + ${user.id}}" class="btn-edit">编辑</a>
                <a th:href="@{'/delete/' + ${user.id}}" class="btn-delete">删除</a>
            </td>
        </tr>
    </table>
    <a href="/form" style="text-align: center; margin-top: 20px; display: block;">添加新信息</a>
    <a href="/deleteAll" class="btn-delete-all">删除全部用户信息</a>
</body>

</html>

这里的页面可以通过设置css样式表等方式进行改进

**结果：**可以通过前端创建用户，并加入到mysql数据库中

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