springboot干货——（六）springboot整合mybatis(两种方式)

版权声明：本文为博主原创文章，未经博主允许不得转载。 https://blog.csdn.net/gwd1154978352/article/details/78385945

本博客中介绍了两种整合方式，分别是xml配置和注解

依赖

<dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        
        <!-- mybatis -->
        <dependency>
		    <groupId>org.mybatis.spring.boot</groupId>
		    <artifactId>mybatis-spring-boot-starter</artifactId>
		    <version>1.3.0</version>
		</dependency>
		
		<!-- 数据源 -->
      	<dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.0.19</version>
        </dependency>

这里不引入spring-boot-starter-jdbc依赖，是由于mybatis-spring-boot-starter中已经包含了此依赖。

MyBatis-Spring-Boot-Starter依赖将会提供如下

• 自动检测现有的DataSource
• 将创建并注册SqlSessionFactory的实例，该实例使用SqlSessionFactoryBean将该DataSource作为输入进行传递
• 将创建并注册从SqlSessionFactory中获取的SqlSessionTemplate的实例。
• 自动扫描您的mappers，将它们链接到SqlSessionTemplate并将其注册到Spring上下文，以便将它们注入到您的bean中。

就是说，使用了该Starter之后，只需要定义一个DataSource即可（application.properties中可配置），它会自动创建使用该DataSource的SqlSessionFactoryBean以及SqlSessionTemplate。会自动扫描你的Mappers，连接到SqlSessionTemplate，并注册到Spring上下文中。

数据源配置

注意要加?characterEncoding=UTF-8，否则部分数据库会中文乱码

spring.datasource.url=jdbc:mysql://localhost:3306/test?characterEncoding=UTF-8
spring.datasource.username = root
spring.datasource.password = XXXX
spring.datasource.driver-class-name = com.mysql.jdbc.Driver

运行类

package com.gwd;
import javax.sql.DataSource;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.core.env.Environment;

import com.alibaba.druid.pool.DruidDataSource;

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

	@Autowired
	private Environment env;

	//destroy-method="close"的作用是当数据库连接不使用的时候,就把该连接重新放到数据池中,方便下次使用调用.
	@Bean(destroyMethod =  "close")
	public DataSource dataSource() {
		DruidDataSource dataSource = new DruidDataSource();
		dataSource.setUrl(env.getProperty("spring.datasource.url"));
		dataSource.setUsername(env.getProperty("spring.datasource.username"));//用户名
		dataSource.setPassword(env.getProperty("spring.datasource.password"));//密码
		dataSource.setDriverClassName(env.getProperty("spring.datasource.driver-class-name"));
		dataSource.setInitialSize(2);//初始化时建立物理连接的个数
		dataSource.setMaxActive(20);//最大连接池数量
		dataSource.setMinIdle(0);//最小连接池数量
		dataSource.setMaxWait(60000);//获取连接时最大等待时间，单位毫秒。
		dataSource.setValidationQuery("SELECT 1");//用来检测连接是否有效的sql
		dataSource.setTestOnBorrow(false);//申请连接时执行validationQuery检测连接是否有效
		dataSource.setTestWhileIdle(true);//建议配置为true，不影响性能，并且保证安全性。
		dataSource.setPoolPreparedStatements(false);//是否缓存preparedStatement，也就是PSCache
		return dataSource;
	}
}

bean

package com.gwd.domain;

public class User {
    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 == null ? null : name.trim();
    }
}

Service

package com.gwd.service;

import com.gwd.domain.User;

public interface StuService {
	public User getById(int id);
}

ServiceImpl（和Spring中无二，务必加@Service）

package com.gwd.service.impl;

import java.io.Serializable;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import com.gwd.dao.StuMapper;
import com.gwd.domain.User;
import com.gwd.service.StuService;
@Service
public class StuServiceImpl implements StuService,Serializable{
	/**
	 * 
	 */
	private static final long serialVersionUID = 1L;
	@Autowired
	private StuMapper stuMapper;
	@Override
	public User getById(int id) {
		// TODO Auto-generated method stub
		User user = stuMapper.selectById(id);
		return user;
	}

}

Controller

package com.gwd.controller;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.Controller;
import com.gwd.domain.User;
import com.gwd.service.StuService;

@Controller
public class StuController {
	@Autowired
	private StuService stuService;
	
	@RequestMapping("/index")
	@ResponseBody
	public String index() {
		User stu = stuService.getById(1);
		return stu.getName();
	}
}

---

一.XML配置方式

项目结构图

Application.properties

#加上?characterEncoding=UTF-8，否则部分数据库中文会乱码
spring.datasource.url=jdbc:mysql://localhost:3306/test?characterEncoding=UTF-8
spring.datasource.username = root
spring.datasource.password = XXXX
spring.datasource.driver-class-name = com.mysql.jdbc.Driver
#mapper.xml在Resource下的话配置如下，否则配置为：mybatis.mapper-locations=classpath:com/gwd/movie/dao/mapper/*.xml
mybatis.mapper-locations=classpath:mapper/*.xml
mybatis.type-aliases-package=com.gwd.domain
logging.file=/log/springBootTest.log
server.port=8090

Dao

package com.gwd.dao;

import org.apache.ibatis.annotations.Mapper;

import com.gwd.domain.User;

@Mapper
public interface StuMapper {
	User selectById(int id);
}

注：这边的@Mapper注解也可以不用,直接在运行类上加上@MapperScan(basePackages= {"xxx.xxx.mapper"}),并且推荐使用后者，比较方便，具体如下图

StuMapper.xml(规则和spring整合mybatis一致)

该文件放置到resources文件夹下面，并且需要在Application.properties文件中配置文件地址

<?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.gwd.dao.StuMapper" >
  <resultMap id="BaseResultMap" type="com.gwd.domain.User" >
    <result column="id" property="id" jdbcType="INTEGER" />
    <result column="name" property="name" jdbcType="VARCHAR" />
  </resultMap>
  <sql id="Base_Column_List" >
    id, name
  </sql>
  <select id="selectById" parameterType="java.lang.Integer" resultMap="BaseResultMap">
  	select * from stu where id=#{id}
  </select>
</mapper>

---

二.注解方式

Application.properties

spring.datasource.url=jdbc:mysql://localhost:3306/test?characterEncoding=UTF-8
spring.datasource.username = root
spring.datasource.password = 19940315
spring.datasource.driver-class-name = com.mysql.jdbc.Driver
mybatis.type-aliases-package=com.gwd.domain
logging.file=/log/springBootTest.log
server.port=8090

项目结构

Dao(无需Mapper.xml)

package com.gwd.dao;

import org.apache.ibatis.annotations.*;
import com.gwd.domain.User;

@Mapper
public interface StuMapper {
	@Select("select * from stu where id = #{id}")
    @Results(id = "userMap", value = {
            @Result(column = "id", property = "id", javaType = Integer.class),
            @Result(property = "name", column = "name", javaType = String.class)
    })
	User selectById(@Param("id")int id);
}