这篇文章介绍如何使用jpa和thymeleaf做一个增删改查的示例。
快速上手
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.jdbc.Driver
spring.jpa.properties.hibernate.hbm2ddl.auto=update
spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.MySQL5InnoDBDialect
spring.jpa.show-sql= true
spring.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：springboot(五)：spring data jpa的使用-spring-data-jpa%E7%9A%84%E4%BD%BF%E7%94%A8.html)
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 : ${users}"> 这里会从controler层model set的对象去获取相关的内容，th:each表示会循环遍历对象内容。
其实还有其它的写法，具体的语法内容可以参考这篇文章：springboot(四)：thymeleaf使用详解-thymeleaf%E4%BD%BF%E7%94%A8%E8%AF%A6%E8%A7%A3.html)
修改页面：
<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head>
<meta charset="UTF-8"/>
<title>user</title>
<link rel="stylesheet" th:href="@{/css/bootstrap.css}"></link>
</head>
<body class="container">
<br/>
<h1>修改用户</h1>
<br/><br/>
<div class="with:80%">
<form class="form-horizontal" th:action="@{/edit}" th:object="${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>
添加页面和修改类似就不在贴代码了。
效果图：
这样一个使用jpa和thymeleaf的增删改查示例就完成了。