mybatis-plus結合springboot使用

代碼倉庫：https://gitee.com/DerekAndroid/mybatisPlusDemo.git

mybatis-plus入門使用：

1.sql準備

DROP TABLE IF EXISTS user;

CREATE TABLE user
(
	id BIGINT(20) NOT NULL AUTO_INCREMENT COMMENT '主鍵ID',
	name VARCHAR(30) NULL DEFAULT NULL COMMENT '姓名',
	age INT(11) NULL DEFAULT NULL COMMENT '年齡',
	email VARCHAR(50) NULL DEFAULT NULL COMMENT '郵箱',
	PRIMARY KEY (id)
);

DELETE FROM user;

INSERT INTO user (id, name, age, email) VALUES
(1, 'Jone', 18, '[email protected]'),
(2, 'Jack', 20, '[email protected]'),
(3, 'Tom', 28, '[email protected]'),
(4, 'Sandy', 21, '[email protected]'),
(5, 'Billie', 24, '[email protected]');

2.springboot依賴+配置

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
	<modelVersion>4.0.0</modelVersion>
	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>2.2.6.RELEASE</version>
		<relativePath/> <!-- lookup parent from repository -->
	</parent>
	<groupId>com.example</groupId>
	<artifactId>demo</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<name>mybatisPlusDemo</name>
	<description>Demo project for Spring Boot</description>

	<properties>
		<java.version>1.8</java.version>
	</properties>

	<dependencies>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter</artifactId>
		</dependency>

		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-test</artifactId>
			<scope>test</scope>
			<exclusions>
				<exclusion>
					<groupId>org.junit.vintage</groupId>
					<artifactId>junit-vintage-engine</artifactId>
				</exclusion>
			</exclusions>
		</dependency>

		<dependency>
			<groupId>org.projectlombok</groupId>
			<artifactId>lombok</artifactId>
			<optional>true</optional>
			<version>1.18.8</version>
		</dependency>
		<dependency>
			<groupId>com.baomidou</groupId>
			<artifactId>mybatis-plus-boot-starter</artifactId>
			<version>3.3.1.tmp</version>
		</dependency>
		<!--mysql驅動-->
		<dependency>
			<groupId>mysql</groupId>
			<artifactId>mysql-connector-java</artifactId>
		</dependency>
<!--		mybatis-plus-->
		<dependency>
			<groupId>com.baomidou</groupId>
			<artifactId>mybatis-plus-boot-starter</artifactId>
			<version>3.3.1.tmp</version>
		</dependency>
		<dependency>
			<groupId>com.baomidou</groupId>
			<artifactId>mybatis-plus-generator</artifactId>
			<version>3.3.1.tmp</version>
		</dependency>
		<!-- mybatisplus逆向工程需要的額外jar包，或者freemaker的包也行 -->
		<dependency>
			<groupId>org.apache.velocity</groupId>
			<artifactId>velocity-engine-core</artifactId>
			<version>2.0</version>
		</dependency>
		<dependency>
			<groupId>junit</groupId>
			<artifactId>junit</artifactId>
			<version>4.12</version>
			<scope>compile</scope>
		</dependency>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>
			<scope>compile</scope>
		</dependency>
	</dependencies>

	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
			</plugin>
		</plugins>
	</build>

</project>

3根據創建好的數據庫執行自動生成mybtais配置

package com.example.demo.test;

import com.baomidou.mybatisplus.annotation.DbType;
import com.baomidou.mybatisplus.annotation.IdType;
import com.baomidou.mybatisplus.generator.AutoGenerator;
import com.baomidou.mybatisplus.generator.config.DataSourceConfig;
import com.baomidou.mybatisplus.generator.config.GlobalConfig;
import com.baomidou.mybatisplus.generator.config.PackageConfig;
import com.baomidou.mybatisplus.generator.config.StrategyConfig;
import com.baomidou.mybatisplus.generator.config.rules.NamingStrategy;
import org.junit.Test;

public class SqlGenerator {
    @Test
    public void testGenerator(){
        //0.獲取當前主項目路徑
        String dir = System.getProperty("user.dir");
        String outputDir=dir+"/src/main/java";
        System.out.println("outputDir="+outputDir);
        //1、全局配置
        GlobalConfig config = new GlobalConfig();
        config.setActiveRecord(true)//開啓AR模式
                .setAuthor("agen")//設置作者
                //生成路徑(一般都是生成在此項目的src/main/java下面)
                .setOutputDir(outputDir)
                .setFileOverride(true)//第二次生成會把第一次生成的覆蓋掉
                .setIdType(IdType.AUTO)//主鍵策略
                .setServiceName("%sService")//生成的service接口名字首字母是否爲I，這樣設置就沒有I
                .setBaseResultMap(true)//生成resultMap
                .setBaseColumnList(true);//在xml中生成基礎列
        //2、數據源配置
        DataSourceConfig dataSourceConfig = new DataSourceConfig();
        dataSourceConfig.setDbType(DbType.MYSQL)//數據庫類型
                .setDriverName("com.mysql.jdbc.Driver")
                .setUrl("jdbc:mysql://localhost:3306/boot_user?useUnicode=true&characterEncoding=UTF-8&zeroDateTimeBehavior=convertToNull&serverTimezone=UTC")
                .setUsername("root")
                .setPassword("123");
        //3、策略配置
        StrategyConfig strategyConfig = new StrategyConfig();
        strategyConfig.setCapitalMode(true)//開啓全局大寫命名
                .setNaming(NamingStrategy.underline_to_camel)//下劃線到駝峯的命名方式
                .setTablePrefix("tb_")//表名前綴
                .setEntityLombokModel(true)//使用lombok
                .setInclude("user");//逆向工程使用的表
        //4、包名策略配置
        PackageConfig packageConfig = new PackageConfig();
        packageConfig.setParent("com.example.demo")//設置包名的parent
                .setMapper("mapper")
                .setService("service")
                .setController("controller")
                .setEntity("entity")
                .setXml("mapper");//設置xml文件的目錄
        //5、整合配置
        AutoGenerator autoGenerator = new AutoGenerator();
        autoGenerator.setGlobalConfig(config)
                .setDataSource(dataSourceConfig)
                .setStrategy(strategyConfig)
                .setPackageInfo(packageConfig);
        //6、執行
        autoGenerator.execute();
    }
}

4編寫查詢語句

package com.example.demo.service.impl;

import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.example.demo.entity.User;
import com.example.demo.mapper.UserMapper;
import com.example.demo.service.UserService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

/**
 * <p>
 * 服務實現類
 * </p>
 *
 * @author agen
 * @since 2020-04-17
 */
@Service
@Slf4j
public class UserServiceImpl extends ServiceImpl<UserMapper, User> implements UserService {
    @Autowired
    private UserMapper userMapper;

    public void insertUser(User user) {
        log.info("----------------插入一條記錄： insert user----------------");
        userMapper.insert(user);
    }

    public void serviceSave(User user) {
        log.info("----------------service插入一條記錄： save user----------------");
        save(user);
    }

    public void selectTest() {
        log.info("----------------按主鍵查詢： where id=2----------------");
        User user = userMapper.selectById(1);
        log.info(user.toString());

        log.info("----------------按主鍵查詢： where id=2 ? and age=?----------------");
        User user1 = new User();
        user1.setId(2L);
        user1.setAge(20);
        QueryWrapper<User> queryWrapper = new QueryWrapper<>(user1);
        User user2 = userMapper.selectOne(queryWrapper);
        log.info(user2.toString());

    }
}