Spring Boot 2.x整合PageHelper实现分页

分页查询在实际开发中是必不可少的一项功能，本文在SpringBoot2.x搭建SSM项目上继续整合PageHelper实现分页

【官网】

https://github.com/pagehelper/Mybatis-PageHelper

【本文 Demo】

https://github.com/qidasheng2012/springboot2.x_ssm/tree/branch-page

【maven 依赖】

<dependency>
    <groupId>com.github.pagehelper</groupId>
    <artifactId>pagehelper-spring-boot-starter</artifactId>
    <version>1.2.12</version>
</dependency>

在这里插入图片描述

【application.yml 配置】

pagehelper:
  helper-dialect: mysql
  reasonable: true
  support-methods-arguments: true
  params: count=countsql

配置参数说明
在这里插入图片描述 `

【UserController 】

package com.springboot.ssm.controller;

import com.github.pagehelper.PageInfo;
import com.springboot.ssm.domain.User;
import com.springboot.ssm.service.UserService;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.*;

import java.util.List;

@Slf4j
@Controller
@RequestMapping("/user")
public class UserController {

    @Autowired
    private UserService userService;

    @RequestMapping("/toUserListPage")
    public String toUserListPage() {
        return "user/userList";
    }

    @GetMapping("/getAll")
    @ResponseBody
    public List<User> getAll() {
        return userService.getAll();
    }

    @GetMapping("/page")
    @ResponseBody
    public PageInfo<User> page(User user, @RequestParam(defaultValue = "1") Integer pageNum, @RequestParam(defaultValue = "10") Integer pageSize) {
        return userService.page(user, pageNum, pageSize);
    }
}

【UserService 】

package com.springboot.ssm.service;

import com.github.pagehelper.PageInfo;
import com.springboot.ssm.domain.User;

import java.util.List;

public interface UserService {
    // 查询所有用户信息
    List<User> getAll();

    // 分页查询用户信息
    PageInfo<User> page(User user, Integer pageNum, Integer pageSize);
}

【UserServiceImpl】

package com.springboot.ssm.service.impl;

import com.github.pagehelper.PageHelper;
import com.github.pagehelper.PageInfo;
import com.springboot.ssm.domain.User;
import com.springboot.ssm.mapper.UserMapper;
import com.springboot.ssm.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

@Service
public class UserServiceImpl implements UserService {

    @Autowired
    private UserMapper userMapper;

    @Override
    public List<User> getAll() {
        return userMapper.getAll();
    }

    @Override
    public PageInfo<User> page(User user, Integer pageNum, Integer pageSize) {
        PageHelper.startPage(pageNum, pageSize);
        List<User> list = userMapper.getUsers(user);
        return PageInfo.of(list);
    }

}

【UserMapper 】

package com.springboot.ssm.mapper;

import com.springboot.ssm.domain.User;

import java.util.List;

public interface UserMapper {
    // 查询所有用户信息
    List<User> getAll();

    // 根据条件查询用户信息
    List<User> getUsers(User user);
}

【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.springboot.ssm.mapper.UserMapper">

    <select id="getAll" resultType="User">
        SELECT
            id,
            name,
            age
        FROM user
    </select>

    <select id="getUsers" resultType="User" parameterType="User">
        SELECT
            id,
            name,
            age
        FROM user
        <where>
            <if test="name != null and name != ''">
                and name = #{name}
            </if>
            <if test="age != null">
                and age = #{age}
            </if>
        </where>
    </select>
</mapper>