SpringBoot之Mybatis

王念博客

发布于 2019-07-25 18:21:28

4790

发布于 2019-07-25 18:21:28

前言：群里面经常有人问有木有mybatis的案例，正好有空整合一下。我之前没有用过mybatis，但是跑过简单的增删改查，发现真的很轻量，写sql还比较不错，多表查询也比较方便，但是insert 和update有点麻烦（字段一多写sql会死人）。用了之后我还是希望用jpa,毕竟增删改查都不用自己写，关键可以直接传对象。

springboot和mybatis整合的框架mybatis-spring-boot ：http://www.oschina.net/p/mybatis-spring-boot

有两种实现的方式 xml和注解，用了之后发现xml配置还是挺麻烦的。

update 2016/11/12 差不多用了半年的mybatis发现优点挺多的，在性能和写sql上比较灵活，也不用在实体上手动指定表里字段的映射，结合mybatis自动生成工具发现效率也挺快的，在mybatis配置上我也换了N种配置方式。

1.导入maven依赖

<!--导入mybatis-->
<dependency>
   <groupId>org.mybatis.spring.boot</groupId>
   <artifactId>mybatis-spring-boot-starter</artifactId>
   <version>1.1.1</version>
</dependency>
导入数据库驱动

2.配置数据源

spring.datasource.url =jdbc:mysql://
spring.datasource.username =root
spring.datasource.password =root
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
spring.datasource.max-active=1000
spring.datasource.test-on-borrow=true
spring.datasource.test-on-return=true
#重连
spring.datasource.time-between-eviction-runs-millis=1800000
spring.datasource.num-tests-per-eviction-run=3
#最小生命时间
spring.datasource.min-evictable-idle-time-millis=1800000
spring.datasource.validation-query=SELECT 1

3.创建实体类

package com.wangnian.mybatis.entity;

import java.io.Serializable;

/**
 * Created by 王念 on 2016/4/28.
 */
public class User implements Serializable {
    private Integer id;
    private  String name;

    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;
    }
}

4.创建dao（mapper）

package com.wangnian.mybatis.annotation;
import com.wangnian.mybatis.entity.User;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Param;
import org.apache.ibatis.annotations.Select;

import java.util.List;
import java.util.Map;

/**
 * Created by 王念 on 2016/4/28.
 */
@Mapper
public interface UserDao1 {

    @Select("select * from user where id=#{id}")
    public User selectid(@Param("id") Integer id);


    @Insert("insert into user values(null,#{name})")
    public boolean insertUser(@Param("name") String name);

    @Select("select * from user u join user u1  where u.id=#{id}")
    public List<Map> select(@Param("id") Integer id);

    //XML自动注入
    User selectUserById(@Param("id") Integer id);

}

5.添加mapper文件

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.wangnian.mybatis.xml.UserDao1">
    <select id="selectUserById" resultType="User">
        select * from user where id = #{id}
    </select>
</mapper>

6.配置mybatis自动注入Mapper（三种方式配置，推荐使用第三种，简单）

①种方式

1.添加一个mybatisConfig.xml

2.指定每一个的mappers位置

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <typeAliases>
        <package name="com.wangnian.mybatis.entity"/>
    </typeAliases>
    <mappers>
        <mapper resource="mybatis/mapper/UserMapper.xml"/>
    </mappers>
</configuration>

3.在application.properties里指定mybatisConfig.xml的位置

mybatis.config-location=classPath:mybatisConfig.xml

②种方式

通过javaBean的方式配置

package com.fengchao.config;

import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.SqlSessionTemplate;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.core.io.support.ResourcePatternResolver;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;
import org.springframework.transaction.PlatformTransactionManager;

import javax.sql.DataSource;

/**
 * MyBatis基础配置
 *
 * @author wangnian
 */
@Configuration
@MapperScan("com.fengchao.dao")
//s@EnableTransactionManagement
public class MyBatisConfig {
    @Autowired
    private DataSource dataSource;
    @Bean(name = "sqlSessionFactory")
    public SqlSessionFactory sqlSessionFactoryBean() {
        SqlSessionFactoryBean sqlsession = new SqlSessionFactoryBean();
        sqlsession.setDataSource(dataSource);
        sqlsession.setTypeAliasesPackage("com.fengchao.model");//扫描entity包 使用别名
        org.apache.ibatis.session.Configuration configuration=new org.apache.ibatis.session.Configuration();
        configuration.setUseGeneratedKeys(true);//使用jdbc的getGeneratedKeys获取数据库自增主键值
        configuration.setUseColumnLabel(true);//使用列别名替换列名 select user as User
        configuration.setMapUnderscoreToCamelCase(true);//-自动使用驼峰命名属性映射字段   userId    user_id
        sqlsession.setConfiguration(configuration);
        sqlsession.setFailFast(true);
        //添加XML目录
        ResourcePatternResolver resolver = new PathMatchingResourcePatternResolver();
        try {
            sqlsession.setMapperLocations(resolver.getResources("classpath:mybatis-mapper/*.xml"));
            return sqlsession.getObject();
        } catch (Exception e) {
            e.printStackTrace();
            throw new RuntimeException(e);
        }
    }
    @Bean
    public SqlSessionTemplate sqlSessionTemplate(SqlSessionFactory sqlSessionFactory) {
        return new SqlSessionTemplate(sqlSessionFactory);
    }


    @Bean
    public PlatformTransactionManager annotationDrivenTransactionManager() {
        return new DataSourceTransactionManager(dataSource);
    }

}

③种方式

直接通过application.properties中配置

#mybatis配置
#指定mapper.xml的位置
mybatis.mapper-locations=classpath:mapper/*.xml
#
mybatis.configuration.mapUnderscoreToCamelCase=true
#
mybatis.configuration.useColumnLabel=true

7.运行test

package com.wangnian.mybatis;

import com.wangnian.mybatis.annotation.UserDao1;
import com.wangnian.mybatis.entity.User;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

import java.util.List;
import java.util.Map;

import static javafx.beans.binding.Bindings.select;

@SpringBootApplication
public class SpringbootmybatisApplication implements CommandLineRunner {

    public static void main(String[] args) {
        SpringApplication.run(SpringbootmybatisApplication.class, args);
    }


    @Autowired
    private UserDao1 userDao1;

  

    @Override
    public void run(String... strings) throws Exception {
        //查询
        User user = userDao1.selectid(1);
        System.out.println(user.getName());
        //插入
        boolean b=  userDao1.insertUser("wangnain");
        System.out.println(b);
       //多表查询
       List<Map> list= userDao1.select(1);
       System.out.println(list.get(1));

       //测试xml注入的方式
       User user1 = userDao1.selectUserById(1);
       System.out.println(user1.getUserName());




    }
}

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