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：
---------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
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。
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：
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
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。
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
@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）
//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
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
<!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/' + ${user.id}}" class="btn-delete">删除</a> </td> </tr> </table> <a href="/form" style="text-align: center; margin-top: 20px; display: block;">添加新信息</a> </body> </html>
edit.html
<!DOCTYPE html> <html xmlns:th="http://www.thymeleaf.org"> <head> <meta charset="UTF-8"> <title>Edit User</title> <style> body { display: flex; align-items: center; height: 100vh; background-color: #f2f2f2; flex-direction: column; flex-wrap: wrap; align-content: center; justify-content: center; } form { width: 400px; padding: 20px; background-color: #fff; box-shadow: 0 0 10px rgba(0, 0, 0, 0.1); text-align: center; } label { display: block; margin-bottom: 10px; font-weight: bold; } input { width: 100%; padding: 8px; margin-bottom: 20px; border: 1px solid #ccc; border-radius: 4px; box-sizing: border-box; } button { padding: 10px 20px; border: none; background-color: #4CAF50; color: white; text-decoration: none; cursor: pointer; } button:hover { background-color: #45a049; } a { display: block; margin-top: 20px; text-align: center; text-decoration: none; color: #4CAF50; font-weight: bold; } a:hover { color: #45a049; } </style> </head> <body> <h1>编辑信息</h1> <form th:action="@{/update}" method="post"> <input type="hidden" th:name="id" th:value="${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
<!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
<!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>
