介绍

TKMybatis 是基于 Mybatis 框架开发的一个工具，内部实现了对单表的基本数据操作，只需要简单继承 TKMybatis 提供的接口，就能够实现无需编写任何 sql 即能完成单表操作。

添加依赖

添加TKMybatis 依赖

<dependency><groupId>tk.mybatis</groupId><artifactId>mapper-spring-boot-starter</artifactId><version>2.1.5</version>
</dependency>
<dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><scope>runtime</scope>
</dependency><dependency><groupId>org.projectlombok</groupId><artifactId>lombok</artifactId>
</dependency>

添加TKMybatis 代码生成器插件

 <build><plugins><plugin><groupId>org.mybatis.generator</groupId><artifactId>mybatis-generator-maven-plugin</artifactId><version>1.3.6</version><configuration><configurationFile>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>5.1.47</version></dependency><dependency><groupId>tk.mybatis</groupId><artifactId>mapper</artifactId><version>4.1.5</version></dependency></dependencies></plugin></plugins></build>

生成代码

编写src/main/resources/generator/generatorConfig.xml

<!DOCTYPE generatorConfigurationPUBLIC "-//mybatis.org//DTD MyBatis Generator Configuration 1.0//EN""http://mybatis.org/dtd/mybatis-generator-config_1_0.dtd"><generatorConfiguration><properties resource="generator/config.properties"/><context id="Mysql" targetRuntime="MyBatis3Simple" defaultModelType="flat"><property name="beginningDelimiter" value="`"/><property name="endingDelimiter" value="`"/><plugin type="tk.mybatis.mapper.generator.MapperPlugin"><property name="mappers" value="tk.mybatis.mapper.common.Mapper"/><property name="caseSensitive" value="true"/><property name="lombok" value="Getter,Setter,ToString"/></plugin><jdbcConnection driverClass="${jdbc.driverClass}"connectionURL="${jdbc.url}"userId="${jdbc.user}"password="${jdbc.password}"></jdbcConnection><javaModelGenerator targetPackage="${project.package}.entity"targetProject="src/main/java"/><sqlMapGenerator targetPackage="mapper"targetProject="src/main/resources"/><javaClientGenerator targetPackage="${project.package}.dao"targetProject="src/main/java"type="XMLMAPPER"/><table tableName="${project.tableName}"><generatedKey column="id" sqlStatement="JDBC"/></table></context>
</generatorConfiguration>

编写src/main/resources/generator/config.properties

jdbc.driverClass=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/demo?autoReconnect=true&serverTimezone=Asia/Shanghai
jdbc.user= root
jdbc.password=root#包名
project.package=com.example.helloworld
#表名称
project.tableName=good

其中涉及的数据表

CREATE TABLE `good`  (`id` int(8) NOT NULL AUTO_INCREMENT COMMENT 'id',`good_name` varchar(50) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL COMMENT '商品名称',`good_price` decimal(10, 2) NOT NULL COMMENT '商品价格',`create_time` datetime NOT NULL COMMENT '创建时间',`update_time` datetime NOT NULL COMMENT '更新时间',PRIMARY KEY (`id`) USING BTREE
) ENGINE = InnoDB AUTO_INCREMENT = 1 CHARACTER SET = utf8 COLLATE = utf8_general_ci COMMENT = '商品表' ROW_FORMAT = Dynamic;

配置完成，刷新maven，通过maven插件中的mybatis-generator->mybatis-generator:generate生成代码

新生成的代码如：

├─java
│  └─com
│      └─example
│          └─helloworld
│              │
│              ├─dao
│              │      GoodMapper.java
│              │
│              └─entity
│                      Good.java
│
└─resources│└─mapperGoodMapper.xml

GoodMapper

package com.example.helloworld.dao;import com.example.helloworld.entity.Good;
import tk.mybatis.mapper.common.Mapper;public interface GoodMapper extends Mapper<Good> {
}

Good

package com.example.helloworld.entity;import java.math.BigDecimal;
import java.util.Date;
import javax.persistence.*;
import lombok.Getter;
import lombok.Setter;
import lombok.ToString;@Getter
@Setter
@ToString
@Table(name = "good")
public class Good {/*** id*/@Id@GeneratedValue(generator = "JDBC")private Integer id;/*** 商品名称*/@Column(name = "good_name")private String goodName;/*** 商品价格*/@Column(name = "good_price")private BigDecimal goodPrice;/*** 创建时间*/@Column(name = "create_time")private Date createTime;/*** 更新时间*/@Column(name = "update_time")private Date updateTime;
}

mapper/GoodMapper.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.helloworld.dao.GoodMapper"><resultMap id="BaseResultMap" type="com.example.helloworld.entity.Good"><!--WARNING - @mbg.generated--><id column="id" jdbcType="INTEGER" property="id" /><result column="good_name" jdbcType="VARCHAR" property="goodName" /><result column="good_price" jdbcType="DECIMAL" property="goodPrice" /><result column="create_time" jdbcType="TIMESTAMP" property="createTime" /><result column="update_time" jdbcType="TIMESTAMP" property="updateTime" /></resultMap>
</mapper>

添加扫描

启动类添加@MapperScan 扫描，注意是tk.mybatis.spring.annotation包下的MapperScan

import tk.mybatis.spring.annotation.MapperScan;@MapperScan("com.example.helloworld.dao")
@SpringBootApplication
public class HelloworldApplication {...
}

基本使用

tkmapper 基本方法

方法	描述
Object selectOne(Object record)	根据实体查询单个，字段非空即条件
List select(Object record)	根据实体查询列表，字段非空即条件
List selectAll()	查询所有
int selectCount(Object record)	根据实体计算，字段非空即条件
Object selectByPrimaryKey(Object key)	根据主键查询
boolean existsWithPrimaryKey(Object key)	根据主键判断是否操作
int insert(Object record)	新增
int insertSelective(Object record)	新增不为null的字段
int updateByPrimaryKey(Object record)	按主键更新值
int updateByPrimaryKeySelective(Object record)	按主键更新值不为null的字段
int delete(Object record)	根据实体删除，字段非空即条件
int deleteByPrimaryKey(Object key)	根据主键删除
List selectByExample(Object example)	按条件查询列表
Object selectOneByExample(Object example)	按条件查询单个
int selectCountByExample(Object example)	按条件计数
int deleteByExample(Object example)	按条件删除
int updateByExample(Object record,Object example)	按条件更新值
int updateByExampleSelective(Object record,Object example)	按条件更新值不为null的字段
List selectByExampleAndRowBounds(Object example ,RowBounds row)
List selectByRowBounds(Object record,RowBounds row)

example实例方法

example 用于添加条件，相当于where后面的部分，理论上单表的任何复杂条件查询都可以使用example来完成。

方法	描述
example.setOrderByClause(“字段名 ASC”);	添加升序排列条件，DESC为降序
example.setDistinct(false)	去除重复，boolean型，true为选择不重复的记录。
example.and(Criteria criteria)	为example添加criteria查询条件，关系为与
example.or(Criteria criteria)	为example添加criteria查询条件，关系为或
criteria.andIsNull	添加字段为null的条件
criteria.andIsNotNull	添加字段不为null的条件
criteria.andEqualTo(value)	添加字段等于value条件
criteria.andNotEqualTo(value)	添加字段不等于value条件
criteria.andGreaterThan(value)	添加xxx字段大于value条件
criteria.andGreaterThanOrEqualTo(value)	添加xxx字段大于等于value条件
criteria.andLessThan(value)	添加xxx字段小于value条件
criteria.andLessThanOrEqualTo(value)	添加xxx字段小于等于value条件
criteria.andIn(List<？>)	添加字段值在List<？>条件
criteria.andNotIn(List<？>)	添加字段值不在List<？>条件
criteria.andLike(“%”+value+”%”)	添加字段值为value的模糊查询条件
criteria.andNotLike(“%”+value+”%”)	添加字段值不为value的模糊查询条件
criteria.andBetween(value1,value2)	添加字段值在value1和value2之间条件
criteria.andNotBetween(value1,value2)	添加字段值不在value1和value2之间条件

使用criteria基本字段

Example example = new Example(Good.class);
Criteria criteria = example.createCriteria();
criteria.andEqualTo("id", id);
criteria.andNotEqualTo("good_name", "xxx");
List<Good> list = goodMapper.selectByExample(example);          

不使用criteria基本字段简化操作，但本质还是criteria

Example example = new Example(Good.class);
example.and().andEqualTo("id", id).andNotEqualTo("good_name", "xxx");
List<Good> list = goodMapper.selectByExample(example);