springboot整合mybatis(Mapper.xml和注解两种方式)

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

spring.datasource.url=jdbc:mysql://localhost:3306/test
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.RestController;
import com.gwd.domain.User;
import com.gwd.service.StuService;
 
@RestController
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

spring.datasource.url=jdbc:mysql://localhost:3306/test
spring.datasource.username = root
spring.datasource.password = XXXX
spring.datasource.driver-class-name = com.mysql.jdbc.Driver
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
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);
}
 

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转载自blog.csdn.net/AinUser/article/details/81533439