Mybatis-Plus：快速开始（Spring + Mybatis + Mabatis-Plus）

Posted 2022-03-14 CodeJiao

本节案例承接上节案例

01:Mybatis-Plus：了解Mybatis-Plus、快速开始（Mybatis + Mybatis-Plus，Mybatis-Plus自动做了属性映射）

02：Mybatis-Plus：快速开始（Spring + Mybatis + Mabatis-Plus）

03：Mybatis-Plus：快速开始（SpringBoot + Mybatis + Mybatis）

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1. Spring + Mybatis + Mabatis-Plus

引入了Spring框架，数据源、构建等工作就交给了Spring管理。

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1.1 创建子Module

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1.2 引入Spring相关依赖

pom.xml

<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>mybatis_plus_project</artifactId>
        <groupId>com.tian</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>mybatis_plus_spring_project</artifactId>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
        <spring.version>5.1.6.RELEASE</spring.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>$spring.version</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
            <version>$spring.version</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-test</artifactId>
            <version>$spring.version</version>
        </dependency>
    </dependencies>

</project>

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1.3 配置数据库连接信息

jdbc.properties

jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://127.0.0.1:3306/mp?useUnicode=true&characterEncoding=utf8&autoReconnect=true&allowMultiQueries=true&useSSL=false
jdbc.username=root
jdbc.password=317525

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1.4 编写User对象和UserMapper接口

User.java

package pojo;

import com.baomidou.mybatisplus.annotation.TableName;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

@Data
@NoArgsConstructor
@AllArgsConstructor
@TableName("tb_user")
public class User 

    private Long id;
    private String userName;
    private String password;
    private String name;
    private Integer age;
    private String email;

UserMapper.java

package mapper;


import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import pojo.User;

import java.util.List;

public interface UserMapper extends BaseMapper<User> 
    List<User> findAll();

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1.5 编写Spring核心配置文件

applicationContext.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
		http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context
        http://www.springframework.org/schema/context/spring-context.xsd">

    <context:property-placeholder location="classpath:*.properties"/>

    <!-- 定义数据源 -->
    <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource"
          destroy-method="close">
        <property name="url" value="$jdbc.url"/>
        <property name="username" value="$jdbc.username"/>
        <property name="password" value="$jdbc.password"/>
        <property name="driverClassName" value="$jdbc.driver"/>
        <property name="maxActive" value="10"/>
        <property name="minIdle" value="5"/>
    </bean>

    <!--这里使用MP提供的sqlSessionFactory，完成了Spring与MP的整合-->
    <bean id="sqlSessionFactory" class="com.baomidou.mybatisplus.extension.spring.MybatisSqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource"/>

    </bean> <!--扫描mapper接口，使用的依然是Mybatis原生的扫描器-->
    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <property name="basePackage" value="mapper"/>
    </bean>

</beans>

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1.6 编写测试文件

TestMybatisSpring.java

import mapper.UserMapper;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import pojo.User;

import java.util.List;

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = "classpath:applicationContext.xml")
public class TestMybatisSpring 

    @Autowired
    private UserMapper userMapper;

    @Test
    public void testSelectList() 
        List<User> users = this.userMapper.selectList(null);
        for (User user : users) 
            System.out.println(user);
        
    

运行结果： 我们发现报错了，无法解析$jdbc.url

报错原因：

我们把resources粘贴到test目录尽可以正常运行

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1.7 补充说明：如果需要详细的日志信息

请加上log4j的配置文件

log4j.properties

log4j.rootLogger=DEBUG,A1

log4j.appender.A1=org.apache.log4j.ConsoleAppender
log4j.appender.A1.layout=org.apache.log4j.PatternLayout
log4j.appender.A1.layout.ConversionPattern=[%t] [%c]-[%p] %m%n

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