Spring Boot + Jpa + Thymeleaf 增删改查示例

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配置文件

pom 包配置

pom 包里面添加 Jpa 和 Thymeleaf 的相关包引用

<dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-thymeleaf</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-data-jpa</artifactId> </dependency> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> </dependency>

在application.properties中添加配置

spring.datasource.url=jdbc:mysql://127.0.0.1/test?useUnicode=true&characterEncoding=utf-8&serverTimezone=UTC&useSSL=true spring.datasource.username=root spring.datasource.password=root spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driverspring.jpa.properties.hibernate.hbm2ddl.auto=create spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.MySQL5InnoDBDialect spring.jpa.show-sql= truespring.thymeleaf.cache=false

其中propertiesspring.thymeleaf.cache=false是关闭 Thymeleaf 的缓存，不然在开发过程中修改页面不会立刻生效需要重启，生产可配置为 true。

在项目 resources 目录下会有两个文件夹：static目录用于放置网站的静态内容如 css、js、图片；templates 目录用于放置项目使用的页面模板。

启动类

启动类需要添加 Servlet 的支持

@SpringBootApplication public class JpaThymeleafApplication extends SpringBootServletInitializer { @Override protected SpringApplicationBuilder configure(SpringApplicationBuilder application) { return application.sources(JpaThymeleafApplication.class); } public static void main(String[] args) throws Exception { SpringApplication.run(JpaThymeleafApplication.class, args); } }

数据库层代码

实体类映射数据库表

@Entity public class User { @Id @GeneratedValue private long id; @Column(nullable = false, unique = true) private String userName; @Column(nullable = false) private String password; @Column(nullable = false) private int age; ... }

继承 JpaRepository 类会自动实现很多内置的方法，包括增删改查。也可以根据方法名来自动生成相关 Sql，具体可以参考：Spring Boot (五)：Spring Data Jpa 的使用

public interface UserRepository extends JpaRepository<User, Long> { User findById(long id); Long deleteById(Long id); }

业务层处理

Service 调用 Jpa 实现相关的增删改查，实际项目中 Service 层处理具体的业务代码。

@Service public class UserServiceImpl implements UserService{ @Autowired private UserRepository userRepository; @Override public List<User> getUserList() { return userRepository.findAll(); } @Override public User findUserById(long id) { return userRepository.findById(id); } @Override public void save(User user) { userRepository.save(user); } @Override public void edit(User user) { userRepository.save(user); } @Override public void delete(long id) { userRepository.delete(id); } }

Controller 负责接收请求，处理完后将页面内容返回给前端。

@Controller public class UserController { @Resource UserService userService; @RequestMapping("/") public String index() { return "redirect:/list"; } @RequestMapping("/list") public String list(Model model) { List<User> users=userService.getUserList(); model.addAttribute("users", users); return "user/list"; } @RequestMapping("/toAdd") public String toAdd() { return "user/userAdd"; } @RequestMapping("/add") public String add(User user) { userService.save(user); return "redirect:/list"; } @RequestMapping("/toEdit") public String toEdit(Model model,Long id) { User user=userService.findUserById(id); model.addAttribute("user", user); return "user/userEdit"; } @RequestMapping("/edit") public String edit(User user) { userService.edit(user); return "redirect:/list"; } @RequestMapping("/delete") public String delete(Long id) { userService.delete(id); return "redirect:/list"; } }

return "user/userEdit"; 代表会直接去 resources 目录下找相关的文件。
return "redirect:/list"; 代表转发到对应的 Controller，这个示例就相当于删除内容之后自动调整到 list 请求，然后再输出到页面。

页面内容

list 列表

<!DOCTYPE html> <html lang="en" xmlns:th="http://www.thymeleaf.org"> <head> <meta charset="UTF-8"/> <title>userList</title> <link rel="stylesheet" th:href="@{/css/bootstrap.css}"></link> </head> <body class="container"> <br/> <h1>用户列表</h1> <br/><br/> <div class="with:80%"> <table class="table table-hover"> <thead> <tr> <th>#</th> <th>User Name</th> <th>Password</th> <th>Age</th> <th>Edit</th> <th>Delete</th> </tr> </thead> <tbody> <tr th:each="user : ${users}"> <th scope="row" th:text="${user.id}">1</th> <td th:text="${user.userName}">neo</td> <td th:text="${user.password}">Otto</td> <td th:text="${user.age}">6</td> <td><a th:href="@{/toEdit(id=${user.id})}">edit</a></td> <td><a th:href="@{/delete(id=${user.id})}">delete</a></td> </tr> </tbody> </table> </div> <div class="form-group"> <div class="col-sm-2 control-label"> <a href="/toAdd" th:href="@{/toAdd}" class="btn btn-info">add</a> </div> </div></body> </html>

效果图：

<tr th:each="user : ${users}"> 这里会从 Controler 层 model set 的对象去获取相关的内容，th:each表示会循环遍历对象内容。

其实还有其它的写法，具体的语法内容可以参考这篇文章：Spring Boot (四)： Thymeleaf 使用详解

修改页面：

<!DOCTYPE html> <html lang="en" xmlns:th="http://www.thymeleaf.org"> <head> <meta charset="UTF-8"/> <title>user</title> <link rel="stylesheet" th:href="@{/css/bootstrap.css}"></link> </head> <body class="container"> <br/> <h1>修改用户</h1> <br/><br/> <div class="with:80%"> <form class="form-horizontal" th:action="@{/edit}" th:object="${user}" method="post"> <input type="hidden" name="id" th:value="*{id}" /> <div class="form-group"> <label for="userName" class="col-sm-2 control-label">userName</label> <div class="col-sm-10"> <input type="text" class="form-control" name="userName" id="userName" th:value="*{userName}" placeholder="userName"/> </div> </div> <div class="form-group"> <label for="password" class="col-sm-2 control-label" >Password</label> <div class="col-sm-10"> <input type="password" class="form-control" name="password" id="password" th:value="*{password}" placeholder="Password"/> </div> </div> <div class="form-group"> <label for="age" class="col-sm-2 control-label">age</label> <div class="col-sm-10"> <input type="text" class="form-control" name="age" id="age" th:value="*{age}" placeholder="age"/> </div> </div> <div class="form-group"> <div class="col-sm-offset-2 col-sm-10"> <input type="submit" value="Submit" class="btn btn-info" />       <a href="/toAdd" th:href="@{/list}" class="btn btn-info">Back</a> </div> </div> </form> </div> </body> </html>