SpringBoot整合MyBatisPlus

SpringBoot整合MyBatisPlus

现在有这样一个需求：在SpringBoot中整合MyBatisPlus，并且使用MyBatis的方式编写一个完整链路的接口，即不使用MyBatisPlus中默认的增删改查

添加依赖

这里要注意我们的mapper.xml文件需要在Pom中通过Resources标签引入，否则会找不到对应的Mapper.xml文件

POM

<project xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://maven.apache.org/POM/4.0.0"
         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>2.5.1version>
    parent>
    <groupId>com.examplegroupId>
    <artifactId>mongo-adminartifactId>
    <version>0.0.1-SNAPSHOTversion>
    <properties>
        <java.version>1.8java.version>
    properties>
    <dependencies>

        <dependency>
            <groupId>com.examplegroupId>
            <artifactId>mongo-coreartifactId>
            <version>0.0.1-SNAPSHOTversion>
        dependency>

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

        
        <dependency>
            <groupId>com.baomidougroupId>
            <artifactId>mybatis-plus-boot-starterartifactId>
            <version>3.4.1version>
        dependency>

        
        <dependency>
            <groupId>mysqlgroupId>
            <artifactId>mysql-connector-javaartifactId>
            <scope>runtimescope>
        dependency>

        
        <dependency>
            <groupId>org.springframework.bootgroupId>
            <artifactId>spring-boot-starter-testartifactId>
            <scope>testscope>
        dependency>

        
        <dependency>
            <groupId>org.projectlombokgroupId>
            <artifactId>lombokartifactId>
            <version>1.18.12version>
        dependency>

        
        <dependency>
            <groupId>com.baomidougroupId>
            <artifactId>mybatis-plus-generatorartifactId>
            <version>3.4.1version>
        dependency>

        
        <dependency>
            <groupId>org.apache.velocitygroupId>
            <artifactId>velocity-engine-coreartifactId>
            <version>2.3version>
        dependency>

        
        <dependency>
            <groupId>io.springfoxgroupId>
            <artifactId>springfox-boot-starterartifactId>
            <version>3.0.0version>
        dependency>

        
        <dependency>
            <groupId>com.alibabagroupId>
            <artifactId>druid-spring-boot-starterartifactId>
            <version>1.1.22version>
        dependency>

        <dependency>
            <groupId>log4jgroupId>
            <artifactId>log4jartifactId>
            <version>1.2.17version>
        dependency>

        
        <dependency>
            <groupId>com.github.pagehelpergroupId>
            <artifactId>pagehelper-spring-boot-starterartifactId>
            <version>1.3.0version>
        dependency>

    dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.bootgroupId>
                <artifactId>spring-boot-maven-pluginartifactId>
            plugin>
        plugins>
        <resources>
            <resource>
                <directory>src/main/javadirectory>
                
                <includes>
                    <include>**/*.xmlinclude>
                includes>
            resource>
            
            <resource>
                <directory>src/main/resourcesdirectory>
                <includes>
                    <include>**/*.ymlinclude>
                    <include>**/*.propertiesinclude>
                    <include>**/*.xmlinclude>
                includes>
            resource>
        resources>
    build>


project>

YML

#spring:
#  datasource:
#    type: com.alibaba.druid.pool.DruidDataSource
#    driver-class-name: com.mysql.cj.jdbc.Driver
#    url: jdbc:mysql://localhost:3306/mongo?serverTimezone=UTC
#    username: root
#    password: root

#Spring整合Druid连接池
spring:
  datasource:
    username: root
    password: root
    url: jdbc:mysql://localhost:3306/mongo?characterEncoding=utf-8&serverTimezone=UTC
    driver-class-name: com.mysql.cj.jdbc.Driver
    type: com.alibaba.druid.pool.DruidDataSource
    initial-size: 5
    min-idle: 5
    max-active: 20
    max-wait: 60000
    test-while-idle: true
    time-between-eviction-runs-millis: 60000
    min-evictable-idle-time-millis: 30000
    validation-query: select 'x'
    test-on-borrow: false
    test-on-return: false
    pool-prepared-statements: true
    filters: stat,wall,slf4j
    max-pool-prepared-statement-per-connection-size: 20
    use-global-data-source-stat: true
    connect-properties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=5000

server:
  port: 80

pagehelper:
  helper-dialect: mysql
  reasonable: true
  support-methods-arguments: true

#Spring整合MP
mybatis-plus:
  #定义别名包
  type-aliases-package: com.example.mongoadmin.entity
  #导入映射文件
  mapper-locations: classpath:/mapper/*.xml
  #开启驼峰映射
  configuration:
    map-underscore-to-camel-case: true

#为com.example.mongoadmin.mapper包下的SQL执行打印日志
logging:
  level:
    com.example.mongoadmin.mapper: info

项目结构

编写代码

Mapper

一般来说我们需要查什么内容就在Mapper中定义什么接口就行

package com.example.mongoadmin.mapper;

import com.example.mongoadmin.entity.User;
import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import org.apache.ibatis.annotations.Mapper;

import java.util.List;

/**
 * 

 * 用户管理 Mapper 接口
 * 
 *
 * @author ZJ
 * @since 2023-06-24
 */
@Mapper
public interface UserMapper extends BaseMapper<User> {

    List<User> findAll();

}

Mapper.xml

Mapper中定义的接口具体实现在Mapper.xml文件中，也就是SQL语句

DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.example.mongoadmin.mapper.UserMapper">

    <select id="findAll" resultType="com.example.mongoadmin.entity.User">
        select * from sys_user;
    select>

mapper>

Service

同理，和Mapper接口一样，Service接口定义要实现的规范

package com.example.mongoadmin.service;

import com.example.mongoadmin.entity.User;
import com.baomidou.mybatisplus.extension.service.IService;

import java.util.List;

/**
 * 

 * 用户管理 服务类
 * 
 *
 * @author ZJ
 * @since 2023-06-24
 */
public interface IUserService extends IService<User> {

    List<User> findAll();

}

ServiceImpl

Service接口定义的规范，由实现它的ServiceImpl来具体实现

package com.example.mongoadmin.service.impl;

import com.baomidou.mybatisplus.core.conditions.Wrapper;
import com.baomidou.mybatisplus.core.conditions.segments.MergeSegments;
import com.example.mongoadmin.entity.User;
import com.example.mongoadmin.mapper.UserMapper;
import com.example.mongoadmin.service.IUserService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.util.List;

/**
 * 

 * 用户管理 服务实现类
 * 
 *
 * @author ZJ
 * @since 2023-06-24
 */
@Service
public class UserServiceImpl extends ServiceImpl<UserMapper, User> implements IUserService {

    @Autowired
    private UserMapper userMapper;

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

}

Controller

Controller是系统暴露对外的接口，这里通过依赖注入调用Service的具体实现来与数据库交互内容

package com.example.mongoadmin.controller;

import com.example.mongoadmin.entity.User;
import com.example.mongoadmin.service.IUserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.bind.annotation.RestController;

import javax.annotation.Resource;
import java.util.List;

/**
 * 

 * 用户管理 前端控制器
 * 
 *
 * @author ZJ
 * @since 2023-06-24
 */
@RestController
@RequestMapping("/user")
public class UserController {

    @Autowired
    private IUserService userService;

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

}

测试验证

启动项目，访问接口地址：http://localhost/user/findAll