创建UserMapper.xml关联com.xbb.mybatisplus.tutorial.mapper.UserMapper

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<?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.xbb.mybatisplus.tutorial.mapper.UserMapper">

    <select id="list" resultType="com.xbb.mybatisplus.tutorial.entity.User">
        select * from user
        <where>
            <if test="user.name != null and user.name != ''"> and name = #{user.name} </if>
            <if test="user.email != null and user.email != ''"> and email like '%${user.email}%' </if>
        </where>
    </select>

    <select id="selectPageVo" resultType="com.xbb.mybatisplus.tutorial.entity.User">
        SELECT id,name FROM user
    </select>
    
</mapper>

在UserMapper类中添加两个查询方法

package com.xbb.mybatisplus.tutorial.mapper;

import java.util.List;
import org.apache.ibatis.annotations.Param;
import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.xbb.mybatisplus.tutorial.entity.User;

public interface UserMapper extends BaseMapper<User> {

    Page<User> selectPageVo(Page<User> page);
    
    List<User> list(@Param(value = "user") User user);
    
}

在MybatisPlusTest中添下如下测试方法

    /**
     * 通过在xml编写sql语句并执行查询
     */
    @Test
    public void listByXml() {
        User user = new User();
        List<User> users = userMapper.list(user);
        users.forEach(usr->{
            System.out.println(usr);
        });
        System.out.println("****************************");
        user.setName("Jone");
        users = userMapper.list(user);
        users.forEach(usr->{
            System.out.println(usr);
        });
        System.out.println("****************************");
        user.setName("");
        user.setEmail("@");
        users = userMapper.list(user);
        users.forEach(usr->{
            System.out.println(usr);
        });
    }
    
    /**
     * 通过在xml中自定义sql语句，并执行分页查询
     */
    @Test
    public void pageByXml() {
        Page<User> page = new Page<>();
        page.setSize(2l);
        page.setCurrent(1l);
        Page<User> pageResult = userMapper.selectPageVo(page);
        System.out.println("总页数:" + pageResult.getPages());
        System.out.println("每页显示的最大记录数:"+pageResult.getSize());
        System.out.println("当前页码:" + pageResult.getCurrent());
        System.out.println("符合条件的总记录数:" + pageResult.getTotal());
        pageResult.getRecords().forEach(user -> {
            System.out.println(user);
        });
    }