SpringBoot JPA + H2增删改查示例

下面的例子是基于SpringBoot JPA以及H2数据库来实现的，下面就开始搭建项目吧。

首先看下项目的整体结构：

 具体操作步骤：

打开IDEA，创建一个新的Spring Initializr项目，填写好groupID等信息，依赖勾选web和H2，一路next：

pom.xml关键依赖：

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-data-jpa</artifactId>
    </dependency>
    <dependency>
        <groupId>com.h2database</groupId>
        <artifactId>h2</artifactId>
        <scope>runtime</scope>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
    </dependency>
</dependencies>

 新建controller、domain、service包，创建JPA实体类User：

package com.example.demo.domain;

import org.springframework.format.annotation.DateTimeFormat;

import java.io.Serializable;
import java.time.LocalDate;

import javax.persistence.*;

/**
 * @Description: SpringBoot自动配置会探测到我们使用了H2数据库，它会根据实体类自动创建数据表
 * @author: Alan
 * @Date: 2018/11/30 22:33
 */
@Entity
@Table(name = "user")
public class User implements Serializable{

    private static final long serialVersionUID = 1L;

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;//主键

    @Column(nullable = false)
    private String firstName;//名

    @Column(nullable = false)
    private String lastName;//姓

    @Column(nullable = false)
    private String idCard;//身份证

    @Column(nullable = false)
    @DateTimeFormat(pattern = "yyyy-MM-dd")
    private LocalDate dateOfBirth;//出生日期

    public User() {
    }

    public User(Long id, String firstName, String lastName, String idCard, LocalDate dateOfBirth) {
        this.id = id;
        this.firstName = firstName;
        this.lastName = lastName;
        this.idCard = idCard;
        this.dateOfBirth = dateOfBirth;
    }

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getFirstName() {
        return firstName;
    }

    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }

    public String getLastName() {
        return lastName;
    }

    public void setLastName(String lastName) {
        this.lastName = lastName;
    }

    public String getIdCard() {
        return idCard;
    }

    public void setIdCard(String idCard) {
        this.idCard = idCard;
    }

    public LocalDate getDateOfBirth() {
        return dateOfBirth;
    }

    public void setDateOfBirth(LocalDate dateOfBirth) {
        this.dateOfBirth = dateOfBirth;
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", firstName='" + firstName + '\'' +
                ", lastName='" + lastName + '\'' +
                ", idCard='" + idCard + '\'' +
                ", dateOfBirth=" + dateOfBirth +
                '}';
    }
}

说明：

@Entity: 指明了这是一个entity
@Table：指定生成的表名
@Id: 标记该entity的主键
@GeneratedValue: 提供主键的生成策略

编写配置文件和数据生成语句：

application.properties:

#激活开发环境的的配置文件
spring.profiles.active=dev

application-dev.properties:

#端口设置
server.port=8080
#开启日志记录（日志文件会在10Mb大小的时候被截断，产生新的日志文件）
logging.file=logs/my.log 
spring.h2.console.enabled=true
spring.jpa.open-in-view=true
spring.data.jpa.repositories.bootstrap-mode=default
logging.level.org.hibernate.SQL=debug

import.sql:

INSERT INTO USER (FIRST_NAME, LAST_NAME, ID_CARD, DATE_OF_BIRTH) values ('Steven1', 'Jobs1','630121199206081105', '1998-07-13');
INSERT INTO USER (FIRST_NAME, LAST_NAME, ID_CARD, DATE_OF_BIRTH) values ('Steven2', 'Jobs2','510181199412105672', '1992-07-13');
INSERT INTO USER (FIRST_NAME, LAST_NAME, ID_CARD, DATE_OF_BIRTH) values ('Steven3', 'Jobs','610702199009261457', '1991-07-13');
INSERT INTO USER (FIRST_NAME, LAST_NAME, ID_CARD, DATE_OF_BIRTH) values ('Steven4', 'Jobs','430426198801075355', '1994-07-13');
INSERT INTO USER (FIRST_NAME, LAST_NAME, ID_CARD, DATE_OF_BIRTH) values ('Steven5', 'Michael','420117199502232760', '1998-07-13');
INSERT INTO USER (FIRST_NAME, LAST_NAME, ID_CARD, DATE_OF_BIRTH) values ('Steven6', 'Michael','130203199404122670', '1998-07-13');
INSERT INTO USER (FIRST_NAME, LAST_NAME, ID_CARD, DATE_OF_BIRTH) values ('Steven7', 'Michael','430703197612014630', '1998-07-13');
INSERT INTO USER (FIRST_NAME, LAST_NAME, ID_CARD, DATE_OF_BIRTH) values ('Steven8', 'Michael','350124197805280264', '1998-07-13');
INSERT INTO USER (FIRST_NAME, LAST_NAME, ID_CARD, DATE_OF_BIRTH) values ('Steven9', 'Michael','500230197205314628', '1998-08-19');

 JpaRepository

该接口继承了PagingAndSortingRepository和QueryByExampleExecutor接口，相比CrudRepository接口多了分页和排序功能，因此JpaRepository功能更加全面，如果你不需要分页和排序功能，使用CrudRepository即可。这里我们使用JpaRepository，其定义如下：

@NoRepositoryBean
public interface JpaRepository<T, ID> extends PagingAndSortingRepository<T, ID>, QueryByExampleExecutor<T> {

UserRepository(相当于DAO层，定义了增删改查的方法):

package com.example.demo.service;

import com.example.demo.domain.User;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.Pageable;
import org.springframework.data.domain.Sort;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.jpa.repository.Modifying;
import org.springframework.data.jpa.repository.Query;
import org.springframework.data.repository.query.Param;

import java.time.LocalDate;
import java.util.List;


/**
 * @Description:
 * @author: Alan
 * @Date: 2018/11/30 22:54
 */
public interface UserRepository extends JpaRepository<User, Long>{

    /******************************create***************************************/
    @Override
    User save(User user);
    /******************************read***************************************/
    /**
     * Using sort
     * @param lastName
     * @param sort
     * @return
     */
    @Query("select u from User u where u.lastName like ?1%")
    List<User> findByAndSort(String lastName, Sort sort);

    /**
     * Query creation
     * this translates into the following query:
     * select u from User u where u.idCard = ?1
     */
    User findByIdCard(String idCard);

    /**
     * Native Queries
     * The @Query annotation allows for running native queries by setting the nativeQuery flag to true
     * @param idCard
     * @return
     */
    @Query(value = "select * from user where ID_CARD = ?1", nativeQuery = true)
    User findByIdCard2(String idCard);

    /**
     * Using @Query
     * @param idCard
     * @return
     */
    @Query("select u from User u where u.idCard = ?1")
    User findByIdCard3(String idCard);

    /**
     * Declare native count queries for pagination at the query method by using @Query
     * @param lastName
     * @param pageable
     * @return
     */
    @Query(value = "SELECT * FROM User WHERE LAST_NAME = ?1",
            countQuery = "SELECT count(*) FROM User WHERE LAST_NAME = ?1",
            nativeQuery = true)
    Page<User> findByLastNameWithPageable(String lastName, Pageable pageable);

    /**
     * Using Named Parameters
     * @param firstName
     * @param lastName
     * @return
     */
    @Query("select u from User u where u.firstName = :firstName or u.lastName = :lastName")
    List<User> findByFirstNameOrLastName(@Param("firstName") String firstName,
                                         @Param("lastName") String lastName);

    /**
     * findByDateOfBirth
     * @param date
     * @return
     */
    List<User> findByDateOfBirth(@Param("date") LocalDate date);

    /**
     * find all users
     * @param sort
     * @return
     */
    @Override
    List<User> findAll(Sort sort);
    /****************************update*****************************************/
    /**
     * update a usr by Modifying Queries
     * @param firstName
     * @param idCard
     * @return
     */
    @Modifying
    @Query("update User u set u.firstName = ?1 where u.idCard = ?2")
    int updateUser(String firstName, String idCard);
    /****************************delete*****************************************/
    /**
     * delete a user by idCard
     * @param idCard
     */
    void deleteByIdCard(String idCard);

    /**
     * Using a derived delete query
     * @param idCard
     */
    @Modifying
    @Query("delete from User u where u.idCard = ?1")
    void deleteByIdCard2(String idCard);

    /**
     * delete a user by id
     * @param id
     */
    @Override
    @Modifying
    @Query(value = "delete from user where id = ?1", nativeQuery = true)
    void deleteById(Long id);

}

UserService：

package com.example.demo.service;

import com.example.demo.domain.User;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.Pageable;
import org.springframework.data.domain.Sort;
import org.springframework.data.repository.query.Param;

import java.time.LocalDate;
import java.util.List;

/**
 * @Description:
 * @author: Alan
 * @Date: 2018/12/1 11:44
 */
public interface UserService {

    /****************************create*****************************************/
    User save(User user);
    /****************************read*****************************************/
    List<User> findByAndSort(String lastName, Sort sort);

    User findByIdCard(String idCard);

    User findByIdCard2(String idCard);

    User findByIdCard3(String idCard);

    Page<User> findByLastNameWithPageable(String lastName, Pageable pageable);

    List<User> findByFirstNameOrLastName(String firstName, String lastName);

    List<User> findByDateOfBirth(@Param("date") LocalDate date);

    List<User> findAll(Sort sort);
    /*****************************update****************************************/
    int updateUser(String firstName, String idCard);
    /*****************************delete****************************************/
    void deleteByIdCard(String idCard);

    void deleteByIdCard2(String idCard);

    void deleteById(Long id);

}

UserServiceImpl：（UserService的实现类）

package com.example.demo.service;

import com.example.demo.domain.User;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.Pageable;
import org.springframework.data.domain.Sort;
import org.springframework.data.repository.query.Param;
import org.springframework.stereotype.Component;
import org.springframework.transaction.annotation.Transactional;

import java.time.LocalDate;
import java.util.List;


/**
 * @Description:
 * @author: Alan
 * @Date: 2018/12/1 11:44
 */
@Component("userService")
@Transactional
public class UserServiceImpl implements UserService {
    private UserRepository userRepository;

    UserServiceImpl(UserRepository userRepository) {
        this.userRepository = userRepository;
    }
    /**************************create********************************/
    @Override
    public User save(User user) {
        return userRepository.save(user);
    }
    /**************************read********************************/
    @Override
    public List<User> findByAndSort(String lastName, Sort sort) {
        return userRepository.findByAndSort(lastName, sort);
    }

    @Override
    public User findByIdCard(String idCard) {
        return userRepository.findByIdCard(idCard);
    }

    @Override
    public User findByIdCard2(String idCard) {
        return userRepository.findByIdCard2(idCard);
    }

    @Override
    public User findByIdCard3(String idCard) {
        return userRepository.findByIdCard3(idCard);
    }

    @Override
    public Page<User> findByLastNameWithPageable(String lastName, Pageable pageable) {
        return userRepository.findByLastNameWithPageable(lastName, pageable);
    }

    @Override
    public List<User> findByFirstNameOrLastName(String firstName, String lastName) {
        return userRepository.findByFirstNameOrLastName(firstName, lastName);
    }

    @Override
    public List<User> findByDateOfBirth(@Param("date") LocalDate date) {
        return userRepository.findByDateOfBirth(date);
    }

    @Override
    public List<User> findAll(Sort sort) {
        return userRepository.findAll(sort);
    }

    /**************************update********************************/
    @Override
    public int updateUser(String firstName, String idCard) {
        return userRepository.updateUser(firstName, idCard);
    }
    /**************************delete********************************/
    @Override
    public void deleteByIdCard(String idCard) {
        userRepository.deleteByIdCard(idCard);
    }

    @Override
    public void deleteByIdCard2(String idCard) {
       userRepository.deleteByIdCard2(idCard);
    }

    @Override
    public void deleteById(Long id) {
        userRepository.deleteById(id);
    }

}

UserController：

package com.example.demo.controller;

import com.example.demo.domain.User;
import com.example.demo.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
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.format.annotation.DateTimeFormat;
import org.springframework.transaction.annotation.Transactional;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

import java.time.LocalDate;
import java.util.List;


/**
 * @Description:
 * POST - Create a new resource
 * GET - Read a resource
 * PUT - Update an existing resource
 * DELETE - Delete a resource
 * Tomcat by default is not enabled for HTTP PUT command.
 * 只要让地址栏的参数可以传入函数里面，就能执行修改、新增、删除操作，method用RequestMethod.GET即可
 * 用PUT、POST、DELETE会报405错误，因为输入到地址栏默认使用GET方法
 * 注解@DateTimeFormat(iso = DateTimeFormat.ISO.DATE)主要是解决请求日期无法转成LocalDate的问题
 * @author: Alan
 * @Date: 2018/12/1 10:38
 */
@RestController
public class UserController {

    @Autowired
    private UserService userService;
    /*****************************create*************************************/
    @RequestMapping(value = "/saveUser/{firstName}/{lastName}/{idCard}/{date}",method = RequestMethod.GET)
    @Transactional
    public User saveUser(@PathVariable String firstName,
                         @PathVariable String lastName,
                         @PathVariable String idCard,
                         @PathVariable @DateTimeFormat(iso = DateTimeFormat.ISO.DATE) LocalDate date) {
        User user = new User();//Id是自增长的，不需要传
        user.setFirstName(firstName);
        user.setLastName(lastName);
        user.setIdCard(idCard);
        user.setDateOfBirth(date);
        return userService.save(user);
    }

    /*****************************Read***** ********************************/
    @RequestMapping(value = "/findByAndSort/{lastName}", method = RequestMethod.GET)
    public List<User> findByAndSort(@PathVariable String lastName) {
        Sort sort = new Sort(Sort.Direction.DESC, "firstName");
        return userService.findByAndSort(lastName, sort);
    }

    @RequestMapping(value = "/findByIdCard/{idCard}", method = RequestMethod.GET)
    @Transactional(readOnly = true)
    public User findByIdCard(@PathVariable(name = "idCard")  String idCard) {
        return userService.findByIdCard(idCard);
    }

    @RequestMapping(value = "/findByIdCard2/{idCard}", method = RequestMethod.GET)
    @Transactional(readOnly = true)
    public User findByIdCard2(@PathVariable(name = "idCard") String idCard) {
        return userService.findByIdCard2(idCard);
    }

    @RequestMapping(value = "/findByIdCard3/{idCard}", method = RequestMethod.GET)
    @Transactional(readOnly = true)
    public User findByIdCard3(@PathVariable(name = "idCard") String idCard) {
        return userService.findByIdCard3(idCard);
    }

    @RequestMapping(value = "/findByLastNameWithPageable/{lastName}", method = RequestMethod.GET)
    @Transactional(readOnly = true)
    public Page<User> findByLastNameWithPageable(@PathVariable String lastName) {
        Sort sort = new Sort(Sort.Direction.DESC, "id");
        Pageable pageable = new PageRequest(5,2,sort);
        return userService.findByLastNameWithPageable(lastName, pageable);
    }

    @RequestMapping(value = "/findByFirstNameOrLastName/{firstName}/{lastName}", method = RequestMethod.GET)
    public List<User> findByFirstNameOrLastName(@PathVariable String firstName,
                                                @PathVariable String lastName) {
        return userService.findByFirstNameOrLastName(firstName, lastName);
    }

    @RequestMapping(value = "/findByDateOfBirth/{date}", method = RequestMethod.GET)
    public List<User> findByDateOfBirth(@PathVariable(name = "date")
                                        @DateTimeFormat(iso = DateTimeFormat.ISO.DATE) LocalDate date) {
        return userService.findByDateOfBirth(date);
    }

    @RequestMapping(value = "/findAll", method = RequestMethod.GET)
    public List<User> findAll() {
        Sort sort = new Sort(Sort.Direction.ASC, "id");
        return userService.findAll(sort);
    }
    /*****************************update*************************************/
    @RequestMapping(value = "/updateUser/{firstName}/{idCard}", method = RequestMethod.GET)
    public int updateUser(@PathVariable String firstName, @PathVariable String idCard) {
        return userService.updateUser(firstName, idCard);
    }
    /*****************************delete*************************************/
    @RequestMapping(value = "/deleteByIdCard/{idCard}", method = RequestMethod.GET)
    @Transactional
    public String deleteByIdCard(@PathVariable String idCard) {
        userService.deleteByIdCard(idCard);
        return "SUCCESS";
    }

    @RequestMapping(value = "/deleteByIdCard2/{idCard}", method = RequestMethod.GET)
    @Transactional
    public String deleteByIdCard2(@PathVariable String idCard) {
        userService.deleteByIdCard2(idCard);
        return "SUCCESS";
    }

    @RequestMapping(value = "/deleteById/{id}", method = RequestMethod.GET)
    @Transactional
    public String deleteById(@PathVariable Long id) {
        userService.deleteById(id);
        return "SUCCESS";
    }

}

SpringBoot主类移植com包下，这样其他类才能被扫描到：

启动SpringBoot项目：点击菜单栏的运行按钮或者运行main方法

此时控制台可以看到创建表和插入sql语句的日志：

查询所有用户：

浏览器地址栏输入:http://localhost:8080/findAll

可以看到所有的记录：

[
    {
        "id": 1,
        "firstName": "Steven1",
        "lastName": "Jobs1",
        "idCard": "630121199206081105",
        "dateOfBirth": "1998-07-13"
    },
    {
        "id": 2,
        "firstName": "Steven2",
        "lastName": "Jobs2",
        "idCard": "510181199412105672",
        "dateOfBirth": "1992-07-13"
    },
    {
        "id": 3,
        "firstName": "Steven3",
        "lastName": "Jobs",
        "idCard": "610702199009261457",
        "dateOfBirth": "1991-07-13"
    },
    {
        "id": 4,
        "firstName": "Steven4",
        "lastName": "Jobs",
        "idCard": "430426198801075355",
        "dateOfBirth": "1994-07-13"
    },
    {
        "id": 5,
        "firstName": "Steven5",
        "lastName": "Michael",
        "idCard": "420117199502232760",
        "dateOfBirth": "1998-07-13"
    },
    {
        "id": 6,
        "firstName": "Steven6",
        "lastName": "Michael",
        "idCard": "130203199404122670",
        "dateOfBirth": "1998-07-13"
    },
    {
        "id": 7,
        "firstName": "Steven7",
        "lastName": "Michael",
        "idCard": "430703197612014630",
        "dateOfBirth": "1998-07-13"
    },
    {
        "id": 8,
        "firstName": "Steven8",
        "lastName": "Michael",
        "idCard": "350124197805280264",
        "dateOfBirth": "1998-07-13"
    },
    {
        "id": 9,
        "firstName": "Steven9",
        "lastName": "Michael",
        "idCard": "500230197205314628",
        "dateOfBirth": "1998-08-19"
    }
]

 新增一个user：

http://localhost:8080/saveUser/java/springboot/330987193709193205/1937-09-19

页面会输出新插入的user：

此时再findAll，会发现多了新插入的id为10的记录：

[
    {
        "id": 1,
        "firstName": "Steven1",
        "lastName": "Jobs1",
        "idCard": "630121199206081105",
        "dateOfBirth": "1998-07-13"
    },
    {
        "id": 2,
        "firstName": "Steven2",
        "lastName": "Jobs2",
        "idCard": "510181199412105672",
        "dateOfBirth": "1992-07-13"
    },
    {
        "id": 3,
        "firstName": "Steven3",
        "lastName": "Jobs",
        "idCard": "610702199009261457",
        "dateOfBirth": "1991-07-13"
    },
    {
        "id": 4,
        "firstName": "Steven4",
        "lastName": "Jobs",
        "idCard": "430426198801075355",
        "dateOfBirth": "1994-07-13"
    },
    {
        "id": 5,
        "firstName": "Steven5",
        "lastName": "Michael",
        "idCard": "420117199502232760",
        "dateOfBirth": "1998-07-13"
    },
    {
        "id": 6,
        "firstName": "Steven6",
        "lastName": "Michael",
        "idCard": "130203199404122670",
        "dateOfBirth": "1998-07-13"
    },
    {
        "id": 7,
        "firstName": "Steven7",
        "lastName": "Michael",
        "idCard": "430703197612014630",
        "dateOfBirth": "1998-07-13"
    },
    {
        "id": 8,
        "firstName": "Steven8",
        "lastName": "Michael",
        "idCard": "350124197805280264",
        "dateOfBirth": "1998-07-13"
    },
    {
        "id": 9,
        "firstName": "Steven9",
        "lastName": "Michael",
        "idCard": "500230197205314628",
        "dateOfBirth": "1998-08-19"
    },
    {
        "id": 10,
        "firstName": "java",
        "lastName": "springboot",
        "idCard": "330987193709193205",
        "dateOfBirth": "1937-09-19"
    }
]

 

更新一个user：

将刚插入的id为10的用户的firstName修改成java666：

http://localhost:8080/updateUser/java666/330987193709193205

页面返回1，表示修改成功。

输入：http://localhost:8080/findByIdCard/330987193709193205

可以看到身份证为330987193709193205的firstName确实被修改了：

删除一个user：

输入：http://localhost:8080/deleteById/1

页面显示：

这样id为1的user就被删除了，再输入http://localhost:8080/findAll，id为1的user已不存在：

[
    {
        "id": 2,
        "firstName": "Steven2",
        "lastName": "Jobs2",
        "idCard": "510181199412105672",
        "dateOfBirth": "1992-07-13"
    },
    {
        "id": 3,
        "firstName": "Steven3",
        "lastName": "Jobs",
        "idCard": "610702199009261457",
        "dateOfBirth": "1991-07-13"
    },
    {
        "id": 4,
        "firstName": "Steven4",
        "lastName": "Jobs",
        "idCard": "430426198801075355",
        "dateOfBirth": "1994-07-13"
    },
    {
        "id": 5,
        "firstName": "Steven5",
        "lastName": "Michael",
        "idCard": "420117199502232760",
        "dateOfBirth": "1998-07-13"
    },
    {
        "id": 6,
        "firstName": "Steven6",
        "lastName": "Michael",
        "idCard": "130203199404122670",
        "dateOfBirth": "1998-07-13"
    },
    {
        "id": 7,
        "firstName": "Steven7",
        "lastName": "Michael",
        "idCard": "430703197612014630",
        "dateOfBirth": "1998-07-13"
    },
    {
        "id": 8,
        "firstName": "Steven8",
        "lastName": "Michael",
        "idCard": "350124197805280264",
        "dateOfBirth": "1998-07-13"
    },
    {
        "id": 9,
        "firstName": "Steven9",
        "lastName": "Michael",
        "idCard": "500230197205314628",
        "dateOfBirth": "1998-08-19"
    },
    {
        "id": 10,
        "firstName": "java666",
        "lastName": "springboot",
        "idCard": "330987193709193205",
        "dateOfBirth": "1937-09-19"
    }
]

分页查询：

输入：http://localhost:8080/findByLastNameWithPageable/Michale 

页面显示：lastName为Michale的共有5条记录，page设置：每页2个，共5页

输出结果与程序一致：

 

附录：

注解说明：

@Entity: 指明了这是一个entity
@Table：指定生成的表名
@Id: 标记该entity的主键
@GeneratedValue: 提供主键的生成策略
@Component：声明为一个组件
@Transactional：声明为事务
@Autowired：自动注入
@Query：查询操作
@Modifying：修改操作
@PathVariable：将URL中的请求参数绑定到控制器的入参上
@Override：重写
@Param：声明属性

语句说明：

1、使用SpEL表达式

@Query("select u from User u where u.idCard = ?1")
User findByIdCard3(String idCard);

2、使用原生SQL（需添加nativeQuery=true）

@Query(value = "select * from user where ID_CARD = ?1", nativeQuery = true)
User findByIdCard2(String idCard);

3、使用属性表达式（Property Expressions）

User findByIdCard(String idCard);

（注：上面的方法，JPA会转换成等价的查询语句：select * from User  u where u.idCard = ?1）

官方文档上的JPA标准API：

Keyword	Sample	JPQL snippet
And	findByLastnameAndFirstname	… where x.lastname = ?1 and x.firstname = ?2
Or	findByLastnameOrFirstname	… where x.lastname = ?1 or x.firstname = ?2
Is,Equals	findByFirstname,findByFirstnameIs,findByFirstnameEquals	… where x.firstname = ?1
Between	findByStartDateBetween	… where x.startDate between ?1 and ?2
LessThan	findByAgeLessThan	… where x.age < ?1
LessThanEqual	findByAgeLessThanEqual	… where x.age <= ?1
GreaterThan	findByAgeGreaterThan	… where x.age > ?1
GreaterThanEqual	findByAgeGreaterThanEqual	… where x.age >= ?1
After	findByStartDateAfter	… where x.startDate > ?1
Before	findByStartDateBefore	… where x.startDate < ?1
IsNull	findByAgeIsNull	… where x.age is null
IsNotNull,NotNull	findByAge(Is)NotNull	… where x.age not null
Like	findByFirstnameLike	… where x.firstname like ?1
NotLike	findByFirstnameNotLike	… where x.firstname not like ?1
StartingWith	findByFirstnameStartingWith	… where x.firstname like ?1(parameter bound with appended %)
EndingWith	findByFirstnameEndingWith	… where x.firstname like ?1(parameter bound with prepended %)
Containing	findByFirstnameContaining	… where x.firstname like ?1(parameter bound wrapped in %)
OrderBy	findByAgeOrderByLastnameDesc	… where x.age = ?1 order by x.lastname desc
Not	findByLastnameNot	… where x.lastname <> ?1
In	findByAgeIn(Collection<Age> ages)	… where x.age in ?1
NotIn	findByAgeNotIn(Collection<Age> ages)	… where x.age not in ?1
True	findByActiveTrue()	… where x.active = true
False	findByActiveFalse()	… where x.active = false
IgnoreCase	findByFirstnameIgnoreCase	… where UPPER(x.firstame) = UPPER(?1)

4、使用命名参数（:参数名+@Param）

@Query("select u from User u where u.firstName = :firstName or u.lastName = :lastName")
List<User> findByFirstNameOrLastName(@Param("firstName") String firstName,
                                     @Param("lastName") String lastName);

H2数据库控制台：

地址栏输入http://localhost:8080/h2-console/进入H2控制台

 

程序运行流程图（调用关系）：

 

以上就是SpringBoot JPA增删改查的简单应用，当然你也可以将数据库换成mysql。

官方参考文档：https://docs.spring.io/spring-data/jpa/docs/current/reference/html/