引言：该文档是参考尚硅谷的关于springboot教学视屏后整理而来。当然后面还加入了一些自己从网上收集整理而来的案例！

一、SpringData JPA初步使用

1. springdata简介

2. springboot整合springdata jpa（这是一个最简单的集成案例）

pom.xml引入架包依赖：

<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.atguigu</groupId>
    <artifactId>spring-boot-06-data-jpa</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>spring-boot-06-data-jpa</name>
    <description>Demo project for Spring Boot</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.10.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-jdbc</artifactId>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <!--lombok插件-->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

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


</project>

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application.yml中配置如下：

spring:
  datasource:
    url: jdbc:mysql://192.168.15.22/jpa
    username: root
    password: 123456
    driver-class-name: com.mysql.jdbc.Driver
  jpa:
    hibernate:
#     更新或者创建数据表结构
      ddl-auto: update
#    控制台显示SQL
    show-sql: true

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实体类User:

package com.atguigu.springboot.entity;


import lombok.Data;

import javax.persistence.*;

//使用JPA注解配置映射关系
@Entity //告诉JPA这是一个实体类（和数据表映射的类）
@Table(name = "tbl_user") //@Table来指定和哪个数据表对应;如果省略默认表名就是user；
@Data
public class User {

    @Id //这是一个主键
    @GeneratedValue(strategy = GenerationType.IDENTITY)//自增主键
    private Integer id;

    @Column(name = "last_name",length = 50) //这是和数据表对应的一个列
    private String lastName;
    @Column //省略默认列名就是属性名
    private String email;



}

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数据层接口UserRepository：

package com.atguigu.springboot.repository;

import com.atguigu.springboot.entity.User;
import org.springframework.data.jpa.repository.JpaRepository;

//继承JpaRepository来完成对数据库的操作
public interface UserRepository extends JpaRepository<User,Integer> {
}

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Controller层UserController：这里省略了service，主要是为了测试集成springdata jpa

package com.atguigu.springboot.controller;

import com.atguigu.springboot.entity.User;
import com.atguigu.springboot.repository.UserRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class UserController {

    @Autowired
    UserRepository userRepository;

    @GetMapping("/user/{id}")
    public User getUser(@PathVariable("id") Integer id){
        User user = userRepository.findOne(id);
        return user;
    }

    @GetMapping("/user")
    public User insertUser(User user){
        User save = userRepository.save(user);
        return save;
    }

}

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测试（这里只是通过get请求简单的测试）：

　　查询用户id=2的员工，访问网址：http://localhost:8080/user/2 

　　　　　　返回结果：{"id":2,"lastName":"唐嫣","email":"123@qq.com"}

　　增加一个用户，访问网址：http://localhost:8080/user?lastName=王菲&email=aa  

　　　　　　返回结果为：{"id":3,"lastName":"王菲","email":"aa"}