Spring boot与数据持久化Spring Data JPA集成实战

数据持久化Spring Data JPA
项目集成了spring boot+spring data JPA+thymeleaf
前台代码地址:
https://blog.51cto.com/13501268/2319622
1.JPA理解:是用于管理Java EE和Java SE环境中的持久化,1.以及对象/关系映射的Java API

2.核心概念:

(1)实体:实体表示关系数据库中的表

(2)每个实体实例对应于该表中的行

(3)类必须用javas.persistence.Entity注解

(4)类必须有一个public或protected的的无参构造函数

(5)实体实例被当做值以分离对象方式进行传递(例如通过会话bean的远程业务接口),则该类必须实现Serializable接口

(6)唯一的对象标识符:简单主键(javax.persistence.Id),复合主键(javax.persistence.Embeddedld和javax.persistence.IdClass)

3.关系:

(1)一对一:@OneToOne

(2)一对多:@OneToMany

(3)多对一:@ManyToOne

(4)多对多:@ManyToMany

4.EntityManager接口:

(1)定义用于与持久化上下文进行交互的方法

(2)创建和删除持久化实例,通过实体的主键查找实体

5.Spring Data JPA:

(1)是更大的Spring Data家族的一部分

(2)对基于JPA的数据访问层的增强支持

(3)更容易构建基于使用Spring数据访问技术栈的应用

6.Spring Data JPA常用接口:

(1)CurdRepository:

Spring boot与数据持久化Spring Data JPA集成实战

(2)PagingAndSortingRepository:

Spring boot与数据持久化Spring Data JPA集成实战
7.Spring Data JPA自定义接口:

(1)根据方法名查询,方法名命名一定要遵循规则

Spring boot与数据持久化Spring Data JPA集成实战

8.Spring Data JPA,Hibernate与Spring Boot的集成

(1)环境配置:MySql数据库,Hibernate框架,以及Mysql连接驱动

(2)修改pom.xml文件,添加Spring Data JPA以及数据库连接驱动的依赖:

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
    xmlns:xsi="http://×××w.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.dhtt.spring.boot.blog</groupId>
    <artifactId>spring.data.action</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>spring.data.action</name>
    <description>Demo project for Spring Boot</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.0.RELEASE</version>
        <relativePath /> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</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-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <!-- 内存数据库h3 -->
        <!-- 
        <dependency>
            <groupId>com.h3database</groupId>
            <artifactId>h3</artifactId>
        </dependency>
         -->
        <!-- Mysql数据库连接驱动 -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.46</version>
        </dependency>
        <!-- hibernate持久层框架引入 -->
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-core</artifactId>
            <version>5.3.7.Final</version>
        </dependency>
    </dependencies>

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

</project>

(3)启动项目进行测试,我们发现项目正常启动,说明我们的环境已经配置好了

9.集成后台编码:

(1)User实体:加@Entity注解,唯一标识@Id注解,制定主键生成策略,无参构造改造为protected,防止直接使用,加toString方法,实现Serializable接口;

package com.dhtt.spring.boot.blog.spring.data.action.entity;

import java.io.Serializable;

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

/**
 * user实体
 * 
 * @author QT
 */
@Entity
public class User implements Serializable {

    private static final long serialVersionUID = 516988700978313579L;
    @Id // 主键
    @GeneratedValue(strategy = GenerationType.IDENTITY) // 自增策略
    private Long id; // 用户的唯一标识
    private String name; // 用户名
    private String email; // 用户邮箱

    protected User() { // 防止直接使用
        super();
    }

    public User(Long id, String name, String email) {
        super();
        this.id = id;
        this.name = name;
        this.email = email;
    }

    public Long getId() {
        return id;
    }

    public void setId(Long 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;
    }

    @Override
    public String toString() {
        return "User [id=" + id + ", name=" + name + ", email=" + email + "]";
    }

}

(2)资源库:写userRepository接口继承JpaRepository接口

package com.dhtt.spring.boot.blog.spring.data.action.repository;

import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;

import com.dhtt.spring.boot.blog.spring.data.action.entity.User;
/**
 * User Repository接口
 * @author  QT
 *
 */
@Repository
public interface UserRepository extends JpaRepository<User, Long>{
}

(3)编写userController类,用于与前台进行交互

package com.dhtt.spring.boot.blog.spring.data.action.web.user;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.servlet.ModelAndView;

import com.dhtt.spring.boot.blog.spring.data.action.entity.User;
import com.dhtt.spring.boot.blog.spring.data.action.repository.UserRepository;

@Controller
@RequestMapping("/users")
public class userController {
    @Autowired
    private UserRepository userRepository;

    /**
     * 查询所有用户
     * 
     * @param model
     * @return
     */
    @GetMapping
    public ModelAndView getList(Model model) {
        model.addAttribute("userList", userRepository.findAll());
        model.addAttribute("title", "用户管理");
        return new ModelAndView("users/list", "userModel", model);

    }

    /**
     * 根据Id查询用户
     * 
     * @param id
     * @param model
     * @return
     */
    @GetMapping("{id}")
    public ModelAndView view(@PathVariable("id") Long id, Model model) {
        User user = userRepository.getOne(id);
        model.addAttribute("user", user);
        model.addAttribute("title", "用户查询");
        return new ModelAndView("users/view", "userModel", model);

    }

    /**
     * 创建用户
     * 
     * @param id
     * @param model
     * @return
     */
    @GetMapping("/form")
    public ModelAndView createForm(Model model) {
        model.addAttribute("user", new User(null, null, null));
        model.addAttribute("title", "创建用户");
        return new ModelAndView("users/form", "userModel", model);

    }

    /**
     * 新增或修改用户
     * 
     * @param user
     * @return
     */
    @PostMapping
    public ModelAndView saveOrUpdateUser(User user) {
        user = userRepository.save(user);
        return new ModelAndView("redirect:/users", "userModel", user);

    }

    /**
     * 获取删除用户
     * 
     * @param id
     * @return
     */
    @GetMapping("/delete/{id}")
    public ModelAndView deleteUser(@PathVariable("id") Long id) {
        userRepository.deleteById(id);;
        return new ModelAndView("redirect:/users"); // 重定向到list页面

    }

    /**
     * 获取修改用户界面
     * 
     * @param id
     * @param model
     * @return
     */
    @GetMapping("/modify/{id}")
    public ModelAndView modify(@PathVariable("id") Long id, Model model) {
        User user = userRepository.getOne(id);
        model.addAttribute("user", user);
        model.addAttribute("title", "修改用户");
        return new ModelAndView("users/form", "userModel", model);

    }
}

前台与上一个项目一样,直接粘贴复制就好

前台代码项目地址:

https://blog.51cto.com/13501268/2319622

接下里,启动项目,项目运行正常说明集成成功,下一步我们就将数据进行持久化到数据库中

10.将数据持久化到数据库中
(1)进行数据库配置,配置文件如下

#thymeleaf配置
spring.thymeleaf.encoding=UTF-8
#热部署静态文件,不需要缓存,实时观察文件修改效果
spring.thymeleaf.cache=false
#使用html5标准
spring.thymeleaf.mode=HTML5
spring.thymeleaf.suffix=.html
spring.resources.chain.strategy.content.enabled=true

#数据库连接配置
spring.datasource.url=jdbc:mysql://localhost:3306/blog_test?useUnicode=true&characterEncoding=UTF-8&serverTimezone=GMT%2B8&useSSL=false
spring.datasource.username=root
spring.datasource.password=qitao1996
spring.datasource.driver-class-name=com.mysql.jdbc.Driver

#jpa配置
spring.jpa.show-sql=true
spring.jpa.hibernate.ddl-auto=create-drop

(2)接下来启动数据库,建立数据库
Spring boot与数据持久化Spring Data JPA集成实战
接下来我们启动项目进行操作,我们会发现数据库表成功创建,也可以操作表中数据

至此,Spring boot+Spring Data Jpa+mevan+Thymeleaf集成成功完成

原创文章,作者:3628473679,如若转载,请注明出处:https://blog.ytso.com/tech/opensource/193215.html

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