Spring整合Mybatis（注解版）

Spring整合Mybatis入门（注解版）

步骤一：

创建maven项目在pom.xml文件中导入以下坐标

复制<?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">
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.example</groupId>
    <artifactId>spring_test03</artifactId>
    <version>1.0-SNAPSHOT</version>

    <dependencies>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>5.2.10.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
            <version>5.2.10.RELEASE</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-test</artifactId>
            <version>5.2.10.RELEASE</version>
        </dependency>
        <!--MySQL驱动-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.29</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.mybatis/mybatis -->
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.5.6</version>
        </dependency>

        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis-spring</artifactId>
            <version>1.3.0</version>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.1.16</version>
        </dependency>

        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
            <scope>test</scope>
        </dependency>
    </dependencies>

</project>

步骤二：

在resources资源文件夹下创建jdbc.properties配置文件用来输入数据库中的信息

jdbc.properties

复制jdbc.driver=com.mysql.cj.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/ssmdb?useSSL=false
jdbc.username=root
jdbc.password=123456

在config包下创建配置类SpringConfig，并且创建MybatisConfig与JdbcConfig配置类分别来配置连接数据库的信息以及mybatis的映射关系。

在SpringConfig配置类中通过@Import注解来导入JdbcConfig与MybatisConfig配置类，通过@PropertySource注解来引入资源文件夹下的jdbc.properties文件信息

导入式相比于扫描式的优点：不会导致配置类的臃肿，且在配置类寻找这些功能的时候不需要在一一寻找对应的关联bean。

ps：使用@Import注解手动加入到配置类到核心配置类中，此注解只能够使用一次，在需要多个配置类时需要使用数组的格式导入配置。

SpringConfig配置类

复制package com.zhicheng.lq.config;

import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Import;
import org.springframework.context.annotation.PropertySource;

@Configuration
@ComponentScan("com.zhicheng.lq")
@PropertySource("classpath:jdbc.properties")
@Import({JdbcConfig.class,MybatisConfig.class})
public class SpringConfig {
}

JdbcConfig配置类

由于已经通过导入式的方法让SpringConfig配置类加载到了JdbcConfig配置类，SpringConfig也引入了资源文件夹下的jdbc.properties文件，所以JdbcConfig配置类中可以使用@Value注解使其赋值参数信息。

复制package com.zhicheng.lq.config;

import com.alibaba.druid.pool.DruidDataSource;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;

import javax.sql.DataSource;

public class JdbcConfig {
    @Value("${jdbc.driver}")
    private String driver;
    @Value("${jdbc.url}")
    private String url;
    @Value("${jdbc.username}")
    private String username;
    @Value("${jdbc.password}")
    private String password;

    @Bean
    public DataSource dataSource(){
        DruidDataSource dataSource = new DruidDataSource();
        dataSource.setDriverClassName(driver);
        dataSource.setUrl(url);
        dataSource.setUsername(username);
        dataSource.setPassword(password);
        return dataSource;
    }
}

MybatisConfig配置类

复制package com.zhicheng.lq.config;

import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.mapper.MapperScannerConfigurer;
import org.springframework.context.annotation.Bean;

import javax.sql.DataSource;

public class MybatisConfig {

    @Bean
    public SqlSessionFactoryBean sqlSessionFactory(DataSource dataSource) {
        SqlSessionFactoryBean factoryBean = new SqlSessionFactoryBean();
        factoryBean.setDataSource(dataSource);
        factoryBean.setTypeAliasesPackage("com.zhicheng.lq.entiy");
        return factoryBean;
    }

    @Bean
    public MapperScannerConfigurer mapperScannerConfigurer() {
        MapperScannerConfigurer msc = new MapperScannerConfigurer();
        msc.setBasePackage("com.zhicheng.lq.dao");
        return msc;
    }
}

步骤三：

在entiy包中创建User实体类用来存放数据库获取的信息
完成dao层与serevice层的代码编写

entiy包中的User实体类

复制package com.zhicheng.lq.entiy;

public class User {
    private Integer id;
    private String name;
    private Integer age;

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", age=" + age +
                '}';
    }

    public User(Integer id, String name, Integer age) {
        this.id = id;
        this.name = name;
        this.age = age;
    }

    public User() {
    }

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }
}

dao包中的UserDao接口类

复制package com.zhicheng.lq.dao;

import com.zhicheng.lq.entiy.User;
import org.apache.ibatis.annotations.Select;

import java.util.List;

public interface UserDao {
    @Select("select * from tbl_user")
    List<User> selectAll();
}

service层中的UserService接口类

复制package com.zhicheng.lq.service;

import com.zhicheng.lq.entiy.User;

import java.util.List;

public interface UserService {
    List<User> getAllUser();
}

serevice层中的UserServiceImp实现类

复制package com.zhicheng.lq.service.Imp;

import com.zhicheng.lq.dao.UserDao;
import com.zhicheng.lq.entiy.User;
import com.zhicheng.lq.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;
@Service
public class UserServiceImp implements UserService {
    @Autowired
    private UserDao userDao;

    public List<User> getAllUser() {
        return userDao.selectAll();
    }
}

步骤四：

编写测试类Test用于测试结果

Tset测试类

复制package com.zhicheng.lq;

import com.zhicheng.lq.config.SpringConfig;
import com.zhicheng.lq.service.UserService;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;

public class Tset {

    public static void main(String[] args) {
        ApplicationContext ac = new AnnotationConfigApplicationContext(SpringConfig.class);
        UserService userService=ac.getBean(UserService.class);
        System.out.println(userService.getAllUser());
    }
}