SpringBoot+Jpa+Thymeleaf实现增删改查

这篇文章介绍如何使用 Jpa 和 Thymeleaf 做一个增删改查的示例。

1、pom依赖

pom 包里面添加Jpa 和 Thymeleaf 的相关包引用

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
	
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.0.RELEASE</version>
    </parent>

    <groupId>com.example</groupId>
    <artifactId>spring-boot-jpa-thymeleaf-curd</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>spring-boot-jpa-thymeleaf-curd</name>
    <description>spring-boot-jpa-thymeleaf-curd</description>

    <properties>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>

        <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>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <optional>true</optional>
        </dependency>

    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <fork>true</fork>
                </configuration>
            </plugin>
        </plugins>
    </build>

</project>

2、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.Driver

spring.jpa.properties.hibernate.hbm2ddl.auto=create
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。

3、启动类

启动类需要添加 Servlet 的支持

package com.example;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.builder.SpringApplicationBuilder;
import org.springframework.boot.web.servlet.support.SpringBootServletInitializer;

@SpringBootApplication
public class Application extends SpringBootServletInitializer {

    @Override
    protected SpringApplicationBuilder configure(SpringApplicationBuilder application) {
        return application.sources(Application.class);
    }

    public static void main(String[] args) throws Exception {
        SpringApplication.run(Application.class, args);
    }
}

4、数据库层代码

实体类映射数据库表

package com.example.model;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;

@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;

    public long getId() {
        return id;
    }

    public User setId(long id) {
        this.id = id;
        return this;
    }

    public String getUserName() {
        return userName;
    }

    public User setUserName(String userName) {
        this.userName = userName;
        return this;
    }

    public String getPassword() {
        return password;
    }

    public User setPassword(String password) {
        this.password = password;
        return this;
    }

    public int getAge() {
        return age;
    }

    public User setAge(int age) {
        this.age = age;
        return this;
    }
}

5、 JpaRepository

package com.example.repository;

import com.example.model.User;
import org.springframework.data.jpa.repository.JpaRepository;

public interface UserRepository extends JpaRepository<User, Long> {

    User findById(long id);

    void deleteById(Long id);
}

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。

6、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。

package com.example.service;

import com.example.model.User;

import java.util.List;

public interface UserService {

    public List<User> getUserList();

    public User findUserById(long id);

    public void save(User user);

    public void edit(User user);

    public void delete(long id);

}

package com.example.service.impl;

import com.example.model.User;
import com.example.repository.UserRepository;
import com.example.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

@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.deleteById(id);
    }
}

7、控制层

package com.example.web;

import com.example.model.User;
import com.example.service.UserService;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;

import javax.annotation.Resource;
import java.util.List;

@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";
    }
}

Controller 负责接收请求，处理完后将页面内容返回给前端。

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。

8、页面内容

list 列表 list.html

<!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>

访问http://localhost:8080/，效果如下图所示：
在这里插入图片描述

<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。

点击Add按钮会跳转到新增页面。

新增页面 userAdd.html

<!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>添加用户</h1>
<br/><br/>
<div class="with:80%">
    <form class="form-horizontal"   th:action="@{/add}"  method="post">
        <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" 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" 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" 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" />
                &nbsp; &nbsp; &nbsp;
                <input type="reset" value="Reset" class="btn btn-info" />
            </div>

        </div>
    </form>
</div>
</body>
</html>

在这里插入图片描述

填写数据并且点击Submit按钮，用户添加成功并且跳转到用户列表页面。

在这里插入图片描述

点击edit按钮跳转到用户修改页面。

修改页面 userEdit.html

<!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" />
                &nbsp; &nbsp; &nbsp;
                <a href="/toAdd" th:href="@{/list}" class="btn btn-info">Back</a>
            </div>

        </div>
    </form>
</div>
</body>
</html>

在这里插入图片描述

修改用户的年龄为100然后点击Submit按钮提交修改。

然后跳转到用户列表页面发现数据修改了。

在这里插入图片描述

可以点击delete按钮删除用户。

删除之后跳转到用户列表页面。

在这里插入图片描述

这样一个使用 Jpa 和 Thymeleaf 的增删改查示例就完成了。