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application.yml的配置：

server:
  port: 8888

spring:
  application:
    name: MybatisDemo
  datasource:
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://localhost:3306/test
    username: root
    password: 123456


mybatis:
  type-aliases-package: com.wan.model
  mapper-locations:
    - mapper/*

mybatis-config.xml配置信息：

<?xml version="1.0" encoding="utf-8" ?>

<configuration>

    <typeAliases>
        <package name="com.wan.model"/>
    </typeAliases>

    <mappers>
        <mapper resource="mapper/mysql.xml"/>
    </mappers>
</configuration>

mysql.xml配置信息：

<?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.wan">
    <select id="getUserCount" resultType="Integer">
        select count(1) from user;
    </select>
</mapper>

Class Demo：

package com.wan.controller;

import org.mybatis.spring.SqlSessionTemplate;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController

public class Demo {
    @Autowired

    private SqlSessionTemplate template;

    @GetMapping("/getCount")
    public int getUserCount() {
        return template.selectOne("getUserCount");
    }

}

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启动应用 访问：[http://localhost:8888/getCount] 查询到的user个数为2

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