一个简单jpa例子
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package com.example.demo.entity; import javax.persistence.*; /*使用jpa注解配置映射关系*/ /*告诉jpa这是一个实体类和(数据表映射的类)*/ @Entity @Table(name = "tal_user") public class User { @Id /*这是主键*/ @GeneratedValue(strategy = GenerationType.IDENTITY) /*主键自增*/ private Integer id; @Column(name = "lastName",length = 50)/*这是和数据表对应的一个列*/ private String lastName; @Column /*省略就代表默认属性名就是列名*/ private String email; public Integer getId() { return id; } public void setId(Integer id) { this.id = id; } public String getLastName() { return lastName; } public void setLastName(String lastName) { this.lastName = lastName; } public String getEmail() { return email; } public void setEmail(String email) { this.email = email; } }
package com.example.demo.repository; import com.example.demo.entity.User; import org.springframework.data.jpa.repository.JpaRepository; /*继承jpaRepository来完成对数据库的操作 参数是实体类型和实体类中的Id类型*/ public interface UserRepository extends JpaRepository<User, Integer> { }
package com.example.demo.Controller; import com.example.demo.entity.User; import com.example.demo.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; import java.util.List; @RestController public class UserController { @Autowired UserRepository userRepository; @GetMapping("/user/{id}") public List<User> getUser(@PathVariable("id") Integer id){ User user = userRepository.getOne(id); final List<User> users = userRepository.findAll(); return users; } @GetMapping("/user") public User insertUser(User user){ User save = userRepository.save(user); return save; } }
spring: datasource: username: root password: root url: jdbc:mysql://localhost:3306/jpa?serverTimezone=UTC driver-class-name: com.mysql.cj.jdbc.Driver jpa: hibernate: # 更新或者创建表结构 ddl-auto: update # 控制台显示sql show-sql: true
<dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <scope>8.0.12</scope> </dependency>
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