SpringDataJPA的分页

SpringDataJPA的分页

1.搭建springboot+springdatajpa+lombok的环境

1.1 项目结构

1.2 pom.xml

<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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0modelVersion>
    <parent>
        <groupId>org.springframework.bootgroupId>
        <artifactId>spring-boot-starter-parentartifactId>
        <version>2.2.6.RELEASEversion>
        <relativePath/> 
    parent>
    <groupId>com.stormkaigroupId>
    <artifactId>element-crudartifactId>
    <version>0.0.1-SNAPSHOTversion>
    <name>element-crudname>
    <description>element-cruddescription>

    <properties>
        <java.version>1.8java.version>
    properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.bootgroupId>
            <artifactId>spring-boot-starter-data-jpaartifactId>
        dependency>
        <dependency>
            <groupId>org.springframework.bootgroupId>
            <artifactId>spring-boot-starter-webartifactId>
        dependency>

        <dependency>
            <groupId>org.springframework.bootgroupId>
            <artifactId>spring-boot-devtoolsartifactId>
            <scope>runtimescope>
            <optional>trueoptional>
        dependency>
        <dependency>
            <groupId>mysqlgroupId>
            <artifactId>mysql-connector-javaartifactId>
            <scope>runtimescope>
        dependency>
        <dependency>
            <groupId>org.projectlombokgroupId>
            <artifactId>lombokartifactId>
            <optional>trueoptional>
        dependency>
        <dependency>
            <groupId>org.springframework.bootgroupId>
            <artifactId>spring-boot-starter-testartifactId>
            <scope>testscope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintagegroupId>
                    <artifactId>junit-vintage-engineartifactId>
                exclusion>
            exclusions>
        dependency>
    dependencies>

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

project>

1.3 application.yml

spring:
  datasource:
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://localhost:3306/csdn?characterEncoding=utf-8&useSSL=false&tinyIntlisBit=false&serverTimezone=GMT
    username: root
    password: root
  jpa:
    show-sql: true
    hibernate:
      ddl-auto: update
  devtools:
    restart:
      enabled: true
      additional-paths: src/main/java

server:
  port: 8088

1.4 sql

CREATE TABLE IF NOT EXISTS `user_info` (
  `id` bigint(20) NOT NULL AUTO_INCREMENT,
  `user_name` varchar(50) NOT NULL COMMENT '用户名',
  `password` varchar(32) NOT NULL COMMENT '密码，加密存储',
  `phone` varchar(20) DEFAULT NULL COMMENT '注册手机号',
  `email` varchar(50) DEFAULT NULL COMMENT '注册邮箱',
  `create_time` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP COMMENT '创建时间',
  `update_time` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP COMMENT '修改时间',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=7 DEFAULT CHARSET=utf8 COMMENT='用户表';

INSERT INTO `user_info` (`id`, `user_name`, `password`, `phone`, `email`, `create_time`, `update_time`) VALUES
	(2, 'Kevin1', '123456', '13110477888', '[email protected]', '2020-01-08 21:15:27', '2020-04-29 00:13:26'),
	(3, 'Lily', '123456', '13110477888', '[email protected]', '2020-01-08 21:16:17', '2020-01-08 21:16:17'),
	(4, 'Rose', '123456', '13110477888', '[email protected]', '2020-01-08 21:16:34', '2020-01-08 21:16:34'),
	(5, 'Vivian', '123456', '13110477888', '[email protected]', '2020-01-08 21:17:01', '2020-01-08 21:17:01'),
	(6, 'Andrew', '123456', '13110477888', '[email protected]', '2020-01-08 21:17:23', '2020-01-08 21:17:23');

1.4 entity

User.java

@Data
@Entity
@Table(name="user_info")
public class User {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Integer id;

    private String userName;

    private String password;

    private String phone;

    private String email;
}

1.5 dao

UserRepository.java

@Repository
public interface UserRepository extends JpaRepository<User,Integer> {
}

1.6 service层

接口：UserService.java

public interface UserService {

    /**
     * 分页查询用户
     * @param pageable
     * @return
     */
    Page<User> findAllUser(Pageable pageable);
}

实现类：UserServiceImpl.java

@Service
public class UserServiceImpl implements UserService {

    @Autowired
    private UserRepository userRepository;


    @Override
    public Page<User> findAllUser(Pageable pageable) {
        return userRepository.findAll(pageable);
    }
}

1.7 测试接口 UserServiceImplTest.java

@SpringBootTest
@Slf4j
class UserServiceImplTest {

    @Autowired
    private UserRepository userRepository;

    @Test
    void findAllUser() {
        Pageable pageable = PageRequest.of(1,2);//page是第几页，size每页显示多少条

        Page<User> userList = userRepository.findAll(pageable);

        log.info("共{}页",userList.getTotalPages());
        log.info("共{}条数据",userList.getTotalElements());
        log.info("第{}页",userList.getNumber());
        log.info(userList.getContent().toString());

        //userList.stream().forEach(user -> log.info(user.toString()));
    }
}

测试结果

Hibernate: select user0_.id as id1_0_, user0_.email as email2_0_, user0_.password as password3_0_, user0_.phone as phone4_0_, user0_.user_name as user_nam5_0_ from user_info user0_ limit ?, ?
Hibernate: select count(user0_.id) as col_0_0_ from user_info user0_
2020-04-29 22:14:18.106  INFO 11740 --- [           main] c.s.service.impl.UserServiceImplTest     : 共3页
2020-04-29 22:14:18.106  INFO 11740 --- [           main] c.s.service.impl.UserServiceImplTest     : 共5条数据
2020-04-29 22:14:18.106  INFO 11740 --- [           main] c.s.service.impl.UserServiceImplTest     : 第1页
2020-04-29 22:14:18.106  INFO 11740 --- [           main] c.s.service.impl.UserServiceImplTest     : [User(id=4, userName=Rose, password=123456, phone=13110477888, email=xxx@126.com), User(id=5, userName=Vivian, password=123456, phone=13110477888, email=xxx@126.com)]