springboot整合mybatis（映射文件方式和注解方式）
springboot作为一个微服务框架，给我们开发人员提供极大的便利，秉着约定大于配置的原则，通过starter包的形式为我们做了许多默认的配置，在进行数据持久化到关系型数据库时，我们一般都会首选spring data jpa，springboot为我们提供了starter包，只需配置很少的参数，就能满足我们的需求，非常方便。但是当我们遇到一些比较复杂的查询、多表关联查询及动态sql时，mybatis则在这方面更出色，并且在使用mybatis时我们可以通过sql优化来提高查询效率，springboot并没有给我们提供整合mybatis的starter包，因此我们需要自己整合。记录一下我的整合过程，以供后续参考。
本人使用的是sts，新建springboot项目加入web、mysql、mybatis模块，springboot版本2.0.1。
1、pom.xml
<?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>com.example</groupId>
<artifactId>springboot-mybatis</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>springboot-mybatis</name>
<description>Demo project for Spring Boot</description>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.1.0.BUILD-SNAPSHOT</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>1.3.2</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<scope>runtime</scope>
</dependency>
<!-- 分页插件 -->
<dependency>
<groupId>com.github.pagehelper</groupId>
<artifactId>pagehelper-spring-boot-starter</artifactId>
<version>1.2.5</version>
</dependency>
<!-- alibaba的druid数据库连接池 -->
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid-spring-boot-starter</artifactId>
<version>1.1.9</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
<repositories>
<repository>
<id>spring-snapshots</id>
<name>Spring Snapshots</name>
<url>https://repo.spring.io/snapshot</url>
<snapshots>
<enabled>true</enabled>
</snapshots>
</repository>
<repository>
<id>spring-milestones</id>
<name>Spring Milestones</name>
<url>https://repo.spring.io/milestone</url>
<snapshots>
<enabled>false</enabled>
</snapshots>
</repository>
</repositories>
<pluginRepositories>
<pluginRepository>
<id>spring-snapshots</id>
<name>Spring Snapshots</name>
<url>https://repo.spring.io/snapshot</url>
<snapshots>
<enabled>true</enabled>
</snapshots>
</pluginRepository>
<pluginRepository>
<id>spring-milestones</id>
<name>Spring Milestones</name>
<url>https://repo.spring.io/milestone</url>
<snapshots>
<enabled>false</enabled>
</snapshots>
</pluginRepository>
</pluginRepositories>
</project>
2、实体类UserDomain.java
package com.example.demo.model;
public class UserDomain {
private Integer userId;
private String userName;
private String password;
private String phone;
//get和set方法
}
3、持久化接口
package com.example.demo.dao;
import java.util.List;
import com.example.demo.model.UserDomain;
public interface UserDao {
int insert(UserDomain record);
List<UserDomain> selectUsers();
}
4、建表语句，注意数据库的ip和名称
CREATE TABLE t_user( user_id INT NOT NULL PRIMARY KEY AUTO_INCREMENT, user_name VARCHAR(255) NOT NULL , password VARCHAR(255) NOT NULL , phone VARCHAR(255) NOT NULL ) ENGINE=INNODB AUTO_INCREMENT=1000 DEFAULT CHARSET=utf8;
5、service层
package com.example.demo.service;
import com.example.demo.model.UserDomain;
import com.github.pagehelper.PageInfo;
public interface UserService {
int addUser(UserDomain user);
PageInfo<UserDomain> findAllUser(int pageNum, int pageSize);
}
package com.example.demo.service.impl;
import java.util.List;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import com.example.demo.dao.UserDao;
import com.example.demo.model.UserDomain;
import com.example.demo.service.UserService;
import com.github.pagehelper.PageHelper;
import com.github.pagehelper.PageInfo;
@Service(value = "userService")
public class UserServiceImpl implements UserService {
@Autowired
private UserDao userDao;
@Override
public int addUser(UserDomain user) {
return userDao.insert(user);
}
//分页查询
@Override
public PageInfo<UserDomain> findAllUser(int pageNum, int pageSize) {
PageHelper.startPage(pageNum, pageSize);
List<UserDomain> userDomains = userDao.selectUsers();
PageInfo result = new PageInfo(userDomains);
return result;
}
}
6、控制层
package com.example.demo.controller;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.ResponseBody;
import com.example.demo.model.UserDomain;
import com.example.demo.service.UserService;
@Controller
@RequestMapping(value = "/user")
public class UserController {
@Autowired
private UserService userService;
@ResponseBody
@PostMapping("/add")
public int addUser(UserDomain user){
return userService.addUser(user);
}
@ResponseBody
@GetMapping("/all")
public Object findAllUser(
@RequestParam(name = "pageNum", required = false, defaultValue = "1")
int pageNum,
@RequestParam(name = "pageSize", required = false, defaultValue = "10")
int pageSize){
return userService.findAllUser(pageNum,pageSize);
}
}
7、application.yml
server:
port: 8080
spring:
datasource:
name: mysql_test
type: com.alibaba.druid.pool.DruidDataSource
#druid相关配置
druid:
#监控统计拦截的filters
filters: stat
driver-class-name: com.mysql.jdbc.Driver
#基本属性
url: jdbc:mysql://127.0.0.1:3306/test?useUnicode=true&characterEncoding=UTF-8&allowMultiQueries=true
username: root
password: root
#配置初始化大小/最小/最大
initial-size: 1
min-idle: 1
max-active: 20
#获取连接等待超时时间
max-wait: 60000
#间隔多久进行一次检测，检测需要关闭的空闲连接
time-between-eviction-runs-millis: 60000
#一个连接在池中最小生存的时间
min-evictable-idle-time-millis: 300000
validation-query: SELECT 'x'
test-while-idle: true
test-on-borrow: false
test-on-return: false
#打开PSCache，并指定每个连接上PSCache的大小。oracle设为true，mysql设为false。分库分表较多推荐设置为false
pool-prepared-statements: false
max-pool-prepared-statement-per-connection-size: 20
mybatis:
mapper-locations: classpath:mapper/*.xml
type-aliases-package: com.example.demo.model
#pagehelper
pagehelper:
helperDialect: mysql
reasonable: true
supportMethodsArguments: true
params: count=countSql
returnPageInfo: check
8、UserMapper.xml
<?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.example.demo.dao.UserDao" >
<sql id="BASE_TABLE">
t_user
</sql>
<sql id="BASE_COLUMN">
userId,userName,password,phone
</sql>
<insert id="insert" parameterType="com.example.demo.model.UserDomain">
INSERT INTO
<include refid="BASE_TABLE"/>
<trim prefix="(" suffix=")" suffixOverrides=",">
userName,password,
<if test="phone != null">
phone,
</if>
</trim>
<trim prefix="VALUES(" suffix=")" suffixOverrides=",">
#{userName, jdbcType=VARCHAR},#{password, jdbcType=VARCHAR},
<if test="phone != null">
#{phone, jdbcType=VARCHAR},
</if>
</trim>
</insert>
<select id="selectUsers" resultType="com.example.demo.model.UserDomain">
SELECT
<include refid="BASE_COLUMN"/>
FROM
<include refid="BASE_TABLE"/>
</select>
</mapper>
9、项目目录结构如下
在项目启动类SpringbootMybatisApplication上加上@MapperScan("com.example.demo.dao")注解，以便spring容器可以扫描到持久化接口，创建对应的代理类。springboot默认为mybatis、jpa、jdbc等开启了事务，如果需要开启事务，则在service层对应的方法上加上@Transactional即可。启动项目，访问localhost:8080/user/add,添加用户；访问localhost:8080/user/all，可以看到分页查询效果。
补充：相比与映射文件方式，注解方式会更加方便，但是功能有限，使用注解方式只需做如下修改即可
1、持久化接口修改为如下
package com.example.demo.dao;
import java.util.List;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Param;
import org.apache.ibatis.annotations.Select;
import com.example.demo.model.UserDomain;
@Mapper
public interface UserDao {
@Insert("INSERT INTO t_user(name, password, phone) VALUES(#{name}, #{password}, #{phone})")
int insert(@Param("name") String name, @Param("password") String password, @Param("phone") String phone);
@Select("SELECT * FROM t_user ")
List<UserDomain> selectUsers();
}
2、删除掉UserMappper.xml文件即可。
