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Spring整合MyBatis

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血与泪的教训

之前少导了个依赖 spring-orm

提前准备

开启注解支持

spring配置文件中加上

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<context:component-scan base-package="com.czw"></context:component-scan>

一个接口

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public interface IAccountMapper {
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    String getFirst();
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}

一个业务层

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@Service
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public class AccountServiceImpl implements IAccountService {
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    @Autowired
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    private IAccountMapper accountMapper;
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	//自动注入接口实现
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    public String getFirst(){
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        return accountMapper.getFirst();
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    }
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}

一张表

一个对应接口的xml文件

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<?xml version="1.0" encoding="utf-8" ?>
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<!DOCTYPE mapper
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        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
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        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
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<mapper namespace="com.czw.mapper.IAccountMapper">
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    <!--名称空间和接口全类名对应-->
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    <select id="getFirst" resultType="String">
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        <!--方法也要对应方法名-->
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        select username from user where user_id=1;
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    </select>
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</mapper>

再续前缘

首先，导好坐标

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<?xml version="1.0" encoding="UTF-8"?>
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<project xmlns="http://maven.apache.org/POM/4.0.0"
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         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
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         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
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    <modelVersion>4.0.0</modelVersion>
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    <groupId>org.example</groupId>
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    <artifactId>SpringLearning</artifactId>
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    <version>1.0-SNAPSHOT</version>
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    <dependencies>
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        <dependency><!--mysql驱动-->
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            <groupId>mysql</groupId>
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            <artifactId>mysql-connector-java</artifactId>
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            <version>8.0.19</version>
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        </dependency>
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        <dependency><!--spring核心之一-->
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            <groupId>org.springframework</groupId>
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            <artifactId>spring-context</artifactId>
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            <version>5.2.3.RELEASE</version>
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        </dependency>
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        <dependency><!--mybatis核心-->
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            <groupId>org.mybatis</groupId>
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            <artifactId>mybatis</artifactId>
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            <version>3.5.3</version>
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        </dependency>
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        <dependency><!--数据源-->
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            <groupId>com.alibaba</groupId>
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            <artifactId>druid</artifactId>
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            <version>1.1.21</version>
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        </dependency>
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        <dependency><!--MyBatis整合Spring核心-->
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            <groupId>org.mybatis</groupId>
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            <artifactId>mybatis-spring</artifactId>
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            <version>1.3.0</version>
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        </dependency>
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        <dependency><!--忘了干嘛的-->
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            <groupId>org.springframework</groupId>
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            <artifactId>spring-tx</artifactId>
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            <version>5.2.3.RELEASE</version>
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        </dependency>
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        <dependency><!--spring对ORM框架的支持-->
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            <groupId>org.springframework</groupId>
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            <artifactId>spring-orm</artifactId>
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            <version>5.2.3.RELEASE</version>
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        </dependency>
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    </dependencies>
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</project>

然后，准备数据库连接

准备外置database.properties文件

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driverClassName=com.mysql.cj.jdbc.Driver
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url=jdbc:mysql://localhost:3306/learningssm?serverTimezone=UTC
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username=root
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password=root

在spring配置文件中引入

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<bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer"><!--引入外部配置文件-->
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    <property name="location" value="classpath:database.properties"/>
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</bean>
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<!--配置连接池-->
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<bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource">
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    <property name="driverClassName" value="${driverClassName}"/>
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    <property name="url" value="${url}"/>
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    <property name="username" value="${username}"/>
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    <property name="password" value="${password}"/>
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</bean>

最后，整合MyBatis

在spring配置文件中加入

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<!--  根据配置文件得到SqlSessionFactory  -->
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<bean id="sqlSessionFactoryBean" class="org.mybatis.spring.SqlSessionFactoryBean">
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    <property name="configLocation" value="classpath:mybatis-config.xml"></property>
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    <property name="dataSource" ref="dataSource"></property>
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    <property name="mapperLocations" value="classpath:mapper/*.xml"></property>
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</bean>
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<!--  将接口实现注入IoC容器  -->
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<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
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    <property name="basePackage" value="com.czw.mapper"></property>
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</bean>

测试

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public static void main(String[] args) {
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    ApplicationContext ac= new ClassPathXmlApplicationContext("applicationContext.xml");
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    //拿到IOC容器
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    IAccountService as= ac.getBean("accountServiceImpl",IAccountService.class);
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    //拿到业务层对象
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    System.out.println(as);
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    System.out.println(as.getFirst());
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    //调用方法
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}

NICE啊，舒服了

总结

头发-1