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:
#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