springboot项目创建笔记17 之《整合mybatis》

一、引入的依赖包
mybatis包，mysql驱动包，mybatis-generator插件，druid数据库连接池，tkMybatis包

1、pom文件添加依赖
mybatis-spring-boot-starter
mysql-connector-java
druid-spring-boot-starter
mapper-spring-boot-starter
pagehelper-spring-boot-starter

<!-- mybatis依赖 -->
<dependency>
	<groupId>org.mybatis.spring.boot</groupId>
	<artifactId>mybatis-spring-boot-starter</artifactId>
	<version>2.1.1</version>
</dependency>
<!-- mysql驱动 -->
<dependency>
	<groupId>mysql</groupId>
	<artifactId>mysql-connector-java</artifactId>
	<version>8.0.19</version>
</dependency>
<!-- druid数据库连接池 -->
<dependency>
	<groupId>com.alibaba</groupId>
	<artifactId>druid-spring-boot-starter</artifactId>
	<version>1.1.21</version>
</dependency>
<!-- tkMybatis -->
<dependency>
	<groupId>tk.mybatis</groupId>
	<artifactId>mapper-spring-boot-starter</artifactId>
	<version>2.1.5</version>
</dependency>
<!-- 分页插件 -->
<dependency>
	<groupId>com.github.pagehelper</groupId>
	<artifactId>pagehelper-spring-boot-starter</artifactId>
	<version>1.2.13</version>
</dependency>

2、pom文件添加插件
mybatis-generator-maven-plugin

<!-- idea下有用 -->
<plugin>
	<groupId>org.mybatis.generator</groupId>
	<artifactId>mybatis-generator-maven-plugin</artifactId>
	<version>1.4.0</version>
	<configuration>
		<configurationFile>${basedir}/src/main/resources/generator/generatorConfig.xml</configurationFile>
		<overwrite>true</overwrite>
		<verbose>true</verbose>
	</configuration>
	<dependencies>
		<dependency>
			<groupId>mysql</groupId>
			<artifactId>mysql-connector-java</artifactId>
			<version>8.0.19</version>
		</dependency>
	</dependencies>
</plugin>

二、配置mybatis
1、添加druid连接池配置
application-dev.yml添加：

#定义数据源
#参考 https://github.com/alibaba/druid/wiki/DruidDataSource%E9%85%8D%E7%BD%AE
spring:
    datasource:
            druid:
                driver-class-name: com.mysql.cj.jdbc.Driver
                type: com.alibaba.druid.pool.DruidDataSource
                url: jdbc:mysql://localhost:3306/webapp2?serverTimezone=UTC
                username: user2
                password: 654321
                #配置监控统计拦截的filters
                filters: stat
                max-active: 20
                initial-size: 1
                max-wait: 60000
                min-idle: 1
                time-between-eviction-runs-millis: 60000
                min-evictable-idle-time-millis: 300000
                test-while-idle: true
                test-on-borrow: false
                test-on-return: false
                pool-prepared-statements: true
                max-open-prepared-statements: 20
                async-init: true

2、添加mybatis读取xml配置
application-dev.yml添加：

#mybatis的相关配置
mybatis:
    #mapper配置文件
    mapper-locations: classpath:com/create/xml/*.xml
    #resultType默认包名
    type-aliases-package: com.create.entity
    #开启驼峰命名
    configuration:
        map-underscore-to-camel-case: true

三、生成三件套
1、在src/main/resources下添加generator目录
建立generatorConfig.xml文件：

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE generatorConfiguration PUBLIC "-//mybatis.org//DTD MyBatis Generator Configuration 1.0//EN" "http://mybatis.org/dtd/mybatis-generator-config_1_0.dtd" >
<generatorConfiguration>
	<context id="context1" targetRuntime="MyBatis3">
		<commentGenerator>
			<property name="suppressAllComments" value="true" /><!-- 取消生成的注释信息 -->
		</commentGenerator>
		<!-- 数据库连接信息 -->
		<jdbcConnection driverClass="com.mysql.cj.jdbc.Driver"
			connectionURL="jdbc:mysql://localhost:3306/webapp2?serverTimezone=UTC"
			userId="user2" password="654321" />
		<!-- 生成实体类 -->
		<javaModelGenerator
			targetPackage="com.create.entity" 
			targetProject="myboot/src/main/java" />
		<!-- 生成mapper.xml文件 -->
		<sqlMapGenerator targetPackage="com.create.xml"
			targetProject="myboot/src/main/java" />
		<!-- 生成mapper接口类 -->
		<javaClientGenerator type="XMLMAPPER"
			targetPackage="com.create.entity" 
			targetProject="myboot/src/main/java">
		</javaClientGenerator>

		<table tableName="tbl_%" schema="webapp2"
			enableCountByExample="false" enableUpdateByExample="false"
			enableDeleteByExample="false" enableSelectByExample="false"
			selectByExampleQueryId="false">
		</table>
	</context>
</generatorConfiguration>

2、生成

四、配置tkMybatis
1、在包com.example.config下，建立配置类DalConfig.java
这里扫描dao要用tk.mybatis.spring.annotation.MapperScan

package com.example.config;

import org.springframework.context.annotation.Configuration;
import org.springframework.transaction.annotation.EnableTransactionManagement;

@Configuration
@tk.mybatis.spring.annotation.MapperScan(basePackages = "com.create.entity")
@EnableTransactionManagement //开启事务注解
public class DalConfig {

}

2、在包com.example.base下，建立通用dao类BaseDao.java

package com.example.base;

import tk.mybatis.mapper.common.Mapper;
import tk.mybatis.mapper.common.MySqlMapper;

public interface BaseDao<T> extends Mapper<T>, MySqlMapper<T> {
	//特别注意，该接口不能被扫描到，否则会出错
}

3、建立一个mapper，继承BaseDao，TblTeacherInfMapperTk.java

package com.create.entity;

import com.example.base.BaseDao;

public interface TblTeacherInfMapperTk extends BaseDao<TblTeacherInf> {

}

4、添加tkMybatis配置
application-dev.yml添加：

扫描二维码关注公众号，回复： 12899219 查看本文章

#tkMybatis配置
mapper:
    #配置继承后的通用DAO接口类
    mappers: com.example.base.BaseDao
    identity: mysql

5、添加测试类MybatisTest.java

package myboot;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;

import com.create.entity.TblTeacherInf;
import com.create.entity.TblTeacherInfMapper;
import com.create.entity.TblTeacherInfMapperTk;
import com.example.myboot.MybootApplication;

@RunWith(SpringRunner.class)
@SpringBootTest(classes = MybootApplication.class)
public class MybatisTest {

	@Autowired
	TblTeacherInfMapper teacherMapper;
	
	@Autowired
	TblTeacherInfMapperTk teacherMapperTk;
	
	@Test
	public void testMybatis() {
		TblTeacherInf teacher = teacherMapper.selectByPrimaryKey(1);
		System.out.println("id is: " + teacher.getId());
		System.out.println("name is: " + teacher.getName());
	}
	
	@Test
	public void testTkMybatis() {
		TblTeacherInf record = new TblTeacherInf();
		record.setId(2);
		TblTeacherInf teacher = teacherMapperTk.selectOne(record);
		System.out.println("id is: " + teacher.getId());
		System.out.println("name is: " + teacher.getName());
	}
}

6、执行成功

五、配置分页插件
1、添加分页插件配置
application-dev.yml添加：

#pagehelper分页插件
pagehelper:
    helperDialect: mysql
    reasonable: true
    supportMethodsArguments: true
    params: count=countSql
    page-size-zero: true

2、添加测试方法
分页查询请求要素：页码、每页大小
分页查询返回要素：页码、每页大小、总记录数
MybatisTest.java添加：

    @Test
	public void testMybatisPageHelper() {
		//使用RowBounds
		//offset是5，limit是5，从第5条开始（不包含）查5条记录
		RowBounds rowBounds = new RowBounds(5, 5);
		//查询
		List<TblTeacherInf> lists = teacherMapperTk.selectByRowBounds(null, rowBounds);
		System.out.println("count is: " + ((Page<TblTeacherInf>)lists).getTotal());
		for(TblTeacherInf tmp : lists) {
			System.out.println("id is: " + tmp.getId());
			System.out.println("name is: " + tmp.getName());
		}
	}
	
	@Test
	public void testTkMybatisPageHelper() {
		//使用PageHelper
		//获取第2页，5条内容，默认查询总数count
		PageHelper.startPage(2, 5);
		//紧跟着的第一个select方法会被分页
		List<TblTeacherInf> lists = teacherMapperTk.selectAll();
		System.out.println("count is: " + ((Page<TblTeacherInf>)lists).getTotal());
		for(TblTeacherInf tmp : lists) {
			System.out.println("id is: " + tmp.getId());
			System.out.println("name is: " + tmp.getName());
		}
	}

注：selectByRowBounds方法第一个参数可以传入一个实体类对象，用于where后面的查询条件

3、执行结果
发现一个问题，用RowBounds分页不返回总条数，PageHelper会返回（RowBounds需要单独再查询总条数）
第一个查询lists对象：
Page{count=false, pageNum=2, pageSize=5, startRow=5, endRow=10, total=-1, pages=1, reasonable=false, pageSizeZero=true}[com.create.entity.TblTeacherInf@af3295f, com.create.entity.TblTeacherInf@27dc81be, com.create.entity.TblTeacherInf@3595086b, com.create.entity.TblTeacherInf@627d35ff, com.create.entity.TblTeacherInf@7157413e]

count is: -1
id is: 6
name is: 赵云
id is: 7
name is: 魏延
id is: 8
name is: 关平
id is: 9
name is: 周仓
id is: 10
name is: 关兴

第二个查询lists对象：
Page{count=true, pageNum=2, pageSize=5, startRow=5, endRow=10, total=20, pages=4, reasonable=true, pageSizeZero=true}[com.create.entity.TblTeacherInf@71e7c13f, com.create.entity.TblTeacherInf@2295566b, com.create.entity.TblTeacherInf@174e1b99, com.create.entity.TblTeacherInf@53a09566, com.create.entity.TblTeacherInf@1c815814]

count is: 20
id is: 6
name is: 赵云
id is: 7
name is: 魏延
id is: 8
name is: 关平
id is: 9
name is: 周仓
id is: 10
name is: 关兴

六、不写sql语句，用tkMybatis的Example对象实现简单的单表多条件查询
可以实现and、or、between、in、isNull、isNotNull、lessThen、greaterThan、like、orderBy等功能
添加测试方法：

    @Test
	public void testExample() {
		//模拟传输对象
		TblTeacherInf teacherDto = new TblTeacherInf();
		teacherDto.setId(100);
		teacherDto.setName("关羽");
		//组建查询条件
		Example example = new Example(TblTeacherInf.class);
		Example.Criteria criteria = example.createCriteria();
		criteria.andEqualTo("id", teacherDto.getId());
		criteria.andEqualTo("name", teacherDto.getName());
		example.setOrderByClause("id desc");
		//查询
		TblTeacherInf tmp = teacherMapperTk.selectOneByExample(example);
		System.out.println("id is: " + tmp.getId());
		System.out.println("name is: " + tmp.getName());
	}

例子打印的sql语句：
SELECT id,name FROM tbl_teacher_inf WHERE ( ( id = ? and name = ? ) ) order by id desc

参考资料：
https://blog.csdn.net/dwf_android/article/details/79359360
https://github.com/abel533/MyBatis-Spring-Boot

注：最新代码上传至https://github.com/csj50/myboot

springboot项目创建笔记17 之《整合mybatis》

猜你喜欢