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

spring:
 datasource:
 url: jdbc:mysql://dbserver.com:3306/user?useUnicode=true&characterEncoding=utf-8
 username: username
 password: password
 driver-class-name: com.mysql.cj.jdbc.Driver

server:
 port: 8080
 compression:
 enabled: true
 servlet:
 context-path: /

/**
 * 使用JPA注解配置映射關(guān)系
 */
@Entity //告訴JPA這是一個(gè)實(shí)體類(lèi)（和數(shù)據(jù)表映射的類(lèi)）
@Table(name = "tbl_user") //@Table來(lái)指定和哪個(gè)數(shù)據(jù)表對(duì)應(yīng)；如果省略，默認(rèn)表名就是該類(lèi)名的小寫(xiě)：user
public class User {
 @Id //表示這個(gè)屬性是數(shù)據(jù)表中的主鍵
 @GeneratedValue(strategy = GenerationType.IDENTITY) //還是一個(gè)自增的主鍵
 private Integer id;
 @Column(name = "last_name",length = 50) //這是和數(shù)據(jù)表對(duì)應(yīng)的一個(gè)列,可以定義其在數(shù)據(jù)表中的名字及長(zhǎng)度
 private String lastName;
 @Column //省略的情況，默認(rèn)列名就是屬性名
 private String email;
}

jpa:
 hibernate:
 ddl-auto: update #定義數(shù)據(jù)表的生成策略。update：更新或者創(chuàng)建數(shù)據(jù)表結(jié)構(gòu)
 show-sql: true #控制臺(tái)顯示sql語(yǔ)句

/**
 * Dao/UserRepository.java
 * 繼承JpaRepository來(lái)完成對(duì)數(shù)據(jù)庫(kù)的操作
 * JpaRepository<T,id>,T表示要進(jìn)行操作的實(shí)體類(lèi)，id表示類(lèi)的主鍵的類(lèi)型
 */
public interface UserRepository extends JpaRepository<User,Integer> {
}

@RestController
@EnableAutoConfiguration
public class UserController {
 @Autowired
 UserRepository userRepository;

 @GetMapping("/user/{id}")
 public User getUser(@PathVariable("id") Integer id) {
 Optional<User> optional = userRepository.findById(id);
 if (optional.isPresent()) {
 User user = optional.get();
 return user;
 } else {
 return new User();
 }
 }

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