SpringBoot与PageHelper的整合使用

一、背景

1.因为公司的需求要使用分页，但是自己写分页的话又非常的麻烦，这时候就使用了一个非常方便的分页插件，跟大家分享下这个分页插件的使用。我使用的是PageHelper这个分页插件。

二、项目结构

三、详细讲解每个组件

1.首先创建一个springboot整合mybatis的项目

1.1.pom.xml

<dependency>
	<groupId>org.springframework.boot</groupId>
	<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
	<groupId>org.mybatis.spring.boot</groupId>
	<artifactId>mybatis-spring-boot-starter</artifactId>
<version>1.3.2</version>
</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>

1.2.application.yml

#开发配置
spring:
  datasource: 
    url: jdbc:mysql://localhost:3306/springboot_db?serverTimezone=UTC
    driver-class-name: com.mysql.cj.jdbc.Driver
    username: root
    password: 123456
#配置mybatis参数
mybatis:
  type-aliases-package: com.example.springbootpagehelper.dto.User
  mapper-locations: classpath:mapper/*.xml

1.3.controller(UserController)

@Controller
@RequestMapping(value = "/api")
public class UserController {
    @Autowired
    private UserService userService;

    @ResponseBody
    @RequestMapping(value = "/users")
    public List<User> users(){
        return userService.selectAllUsers();
    }
}

1.4.service(接口以及实现类)

1.4.1.UserService.java

public interface UserService {
    List<User> selectAllUsers();
}

1.4.2.UserServiceImpl.java

@Service
public class UserServiceImpl implements UserService {
    @Autowired
    private UserDao userDao;

    @Override
    public List<User> selectAllUsers() {
        return userDao.selectAllUsers();
    }
}

1.5.dao(UserDao)

@Mapper
public interface UserDao {
    List<User> selectAllUsers();
}

1.6.dto(User)

public class User {
    private Integer id;
    private String username;
    private String password;
    private String phone;

    public User() {
    }

    public User(Integer id, String username, String password, String phone) {
        this.id = id;
        this.username = username;
        this.password = password;
        this.phone = phone;
    }

    public Integer getId() {
        return id;
    }

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

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public String getPhone() {
        return phone;
    }

    public void setPhone(String phone) {
        this.phone = phone;
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", username='" + username + '\'' +
                ", password='" + password + '\'' +
                ", phone='" + phone + '\'' +
                '}';
    }
}

1.7.mapper(UserMapper.xml)

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.example.springbootpagehelper.dao.UserDao">
    <select id="selectAllUsers" resultType="com.example.springbootpagehelper.dto.User">
        select*from user
    </select>
</mapper>

1.8.建表语句

SET FOREIGN_KEY_CHECKS=0;

-- ----------------------------
-- Table structure for user
-- ----------------------------
DROP TABLE IF EXISTS `user`;
CREATE TABLE `user` (
  `id` int(20) DEFAULT NULL,
  `username` varchar(20) DEFAULT NULL,
  `password` varchar(20) DEFAULT NULL,
  `phone` varchar(20) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

-- ----------------------------
-- Records of user
-- ----------------------------
INSERT INTO `user` VALUES ('1', '张三', '123456', '121334454');
INSERT INTO `user` VALUES ('2', '里斯', '123455', '131414551');
INSERT INTO `user` VALUES ('3', '王五', '131421', '412314442');
INSERT INTO `user` VALUES ('4', '赵六', '114114', '412525235');
INSERT INTO `user` VALUES ('5', '生代', '131241', '141241255');
INSERT INTO `user` VALUES ('6', '萨巴山', '132141', '41241542143');

1.9.到此就完成了项目的创建，就可以启动项目在看结果，在此时还没有使用分页插件。效果如下：

上面的6条数据，下面开始使用分页插件。

四、分页插件的使用

1.pom.xml计入以下依赖

<!-- 分页插件 -->
<dependency>
	<groupId>com.github.pagehelper</groupId>
	<artifactId>pagehelper-spring-boot-starter</artifactId>
    <version>1.2.3</version>
</dependency>

2.config(PageHelperConfiguration.java)

2.1.配置类

@Configuration
public class PageHelperConfiguration {
    @Bean
    public PageHelper pageHelper() {
        PageHelper pageHelper = new PageHelper();
        Properties p = new Properties();
        p.setProperty("offsetAsPageNum", "true");
        p.setProperty("rowBoundsWithCount", "true");
        p.setProperty("reasonable", "true");
        pageHelper.setProperties(p);
        return pageHelper;
    }
}

五、在实现类中实现分页（就一句话）

六、分页结果（就显示3条）

七、结束

上面就是对分页插件的使用，共勉，不懂的请留言！！！