一起来学 SpringBoot 2.x | 第六篇：整合SpringDataJpa

<!-- Spring JDBC 的依赖包，使用 spring-boot-starter-jdbc 或 spring-boot-starter-data-jpa 将会自动获得HikariCP依赖 -->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<!-- MYSQL包 -->
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
</dependency>
<!-- 默认就内嵌了Tomcat 容器，如需要更换容器也极其简单-->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>
<!-- 测试包,当我们使用 mvn package 的时候该包并不会被打入,因为它的生命周期只在 test 之内-->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-test</artifactId>
    <scope>test</scope>
</dependency>

spring.datasource.url=jdbc:mysql://localhost:3306/chapter5?useUnicode=true&characterEncoding=UTF-8&zeroDateTimeBehavior=convertToNull&allowMultiQueries=true&useSSL=false
spring.datasource.password=root
spring.datasource.username=root
#spring.datasource.type
# JPA配置
spring.jpa.hibernate.ddl-auto=update
# 输出日志
spring.jpa.show-sql=true
# 数据库类型
spring.jpa.database=mysql

package com.battcn.entity;

import javax.persistence.GenerationType;
import javax.persistence.Id;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import java.io.Serializable;

/**
 * @author Levin
 * @since 2018/5/7 0007
 */
@Entity(name = "t_user")
public class User implements Serializable {

    private static final long serialVersionUID = 8655851615465363473L;
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    private String username;
    private String password;
    /**
     * TODO 忽略该字段的映射
     */
    @Transient
    private String  email;

    // TODO  省略get set
}

package com.battcn.repository;

import com.battcn.entity.User;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;

import java.util.List;

/**
 * t_user 操作
 *
 * @author Levin
 * @since 2018/5/7 0007
 */
@Repository
public interface UserRepository extends JpaRepository<User, Long> {

    /**
     * 根据用户名查询用户信息
     *
     * @param username 用户名
     * @return 查询结果
     */
    List<User> findAllByUsername(String username);
}

package com.battcn;

import com.battcn.entity.User;
import com.battcn.repository.UserRepository;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.PageRequest;
import org.springframework.data.domain.Pageable;
import org.springframework.data.domain.Sort;
import org.springframework.test.context.junit4.SpringRunner;

import java.util.List;

/**
 * @author Levin
 */
@RunWith(SpringRunner.class)
@SpringBootTest
public class Chapter5ApplicationTests {

    private static final Logger log = LoggerFactory.getLogger(Chapter5ApplicationTests.class);

    @Autowired
    private UserRepository userRepository;

    @Test
    public void test1() throws Exception {
        final User user = userRepository.save(new User("u1", "p1"));
        log.info("[添加成功] - [{}]", user);
        final List<User> u1 = userRepository.findAllByUsername("u1");
        log.info("[条件查询] - [{}]", u1);
        Pageable pageable = PageRequest.of(0, 10, Sort.by(Sort.Order.desc("username")));
        final Page<User> users = userRepository.findAll(pageable);
        log.info("[分页+排序+查询所有] - [{}]", users.getContent());
        userRepository.findById(users.getContent().get(0).getId()).ifPresent(user1 -> log.info("[主键查询] - [{}]", user1));
        final User edit = userRepository.save(new User(user.getId(), "修改后的ui", "修改后的p1"));
        log.info("[修改成功] - [{}]", edit);
        userRepository.deleteById(user.getId());
        log.info("[删除主键为 {} 成功] - [{}]", user.getId());
    }
}