springboot整合Mybatis（一）——入门
一、概述
1.先导
mybatis入门随笔：http://www.cnblogs.com/jiangbei/p/6884641.html
2.引入依赖
<dependency> <groupId>org.mybatis.spring.boot</groupId> <artifactId>mybatis-spring-boot-starter</artifactId> <version>1.3.0</version> </dependency>
//其他必须的依赖还包括mysql连接，web依赖（web项目），此处贴出完整依赖（有部分依赖例如jpa此处可不选）
<?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>demo</artifactId> <version>0.0.1-SNAPSHOT</version> <packaging>jar</packaging> <name>springboot_demo</name> <description>Demo project for Spring Boot</description> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>1.4.7.RELEASE</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.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-thymeleaf</artifactId> </dependency> <!--spring-boot-starter-data-jpa包含spring-data-jpa、spring-orm 和 Hibernate 来支持 JPA--> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-data-jpa</artifactId> </dependency> <!-- mysql连接--> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> </dependency> <!-- mybatis--> <dependency> <groupId>org.mybatis.spring.boot</groupId> <artifactId>mybatis-spring-boot-starter</artifactId> <version>1.3.0</version> </dependency> <!-- 阿里druid连接池 --> <dependency> <groupId>com.alibaba</groupId> <artifactId>druid</artifactId> <version>1.1.6</version> </dependency> <!-- AOP支持--> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-aop</artifactId> </dependency> <!-- spring-boot-devtools热部署支持--> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-devtools</artifactId> <optional>true</optional> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> <dependencies> <!-- spring热部署 --> <!-- <dependency> <groupId>org.springframework</groupId> <artifactId>springloaded</artifactId> <version>1.2.6.RELEASE</version> </dependency>--> </dependencies> </plugin> </plugins> </build> </project>
额外功能（后文陆续补充）
-
- PageHelper 分页插件
- mybatis generator 自动生成代码插件
3.数据源配置
依旧是前文的druid数据源
spring:
datasource:
type: com.alibaba.druid.pool.DruidDataSource
driverClassName: com.mysql.jdbc.Driver
url: jdbc:mysql://127.0.0.1:3306/sakila
username: root
password: root
# druid配置项，默认spring-boot不支持，故需要config类来解析
initialSize: 5
minIdle: 5
maxActive: 20
maxWait: 60000
timeBetweenEvictionRunsMillis: 60000
minEvictableIdleTimeMillis: 300000
validationQuery: SELECT 1 FROM DUAL
testWhileIdle: true
testOnBorrow: false
testOnReturn: false
poolPreparedStatements: true
maxPoolPreparedStatementPerConnectionSize: 20
filters: stat,wall,log4j
connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=5000
4.起步
以下介绍两种整合方式：
传统的mapper.xml映射文件
springboot提倡的无配置注解形式
二、无配置注解形式
1.配置mybatis：
mybatis:
type-aliases-package: com.example.demo.bean
// 包别名简写
2.Bean
沿用之前的bean：girl
package com.example.demo.bean; import javax.validation.constraints.Min; import javax.validation.constraints.Size; /** * girl的bean * * @author zcc ON 2018/2/9 **/ public class Girl { private Integer id; @Size(min = 3, max = 8, message = "名称长度不合法！") private String name; @Min(value = 18, message = "未成年禁止入内！") private Integer age; public Girl() { } public Girl(String name, Integer age) { this.name = name; this.age = age; } 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; } public Integer getAge() { return age; } public void setAge(Integer age) { this.age = age; } @Override public String toString() { return "Girl{" + "id=" + id + ", name='" + name + '\'' + ", age=" + age + '}'; } }
3.Mapper
package com.example.demo.mapper;
import com.example.demo.bean.Girl;
import org.apache.ibatis.annotations.*;
import java.util.List;
/**
* GirlMapper
*
* @author zcc
**/
// @Mapper 这里可以使用@Mapper注解，但是每个mapper都加注解比较麻烦，所以也可以统一配置@MapperScan在扫描路径在application类中
@Mapper
public interface GirlMapper {
@Select("SELECT * FROM girl WHERE id = #{id}")
Girl findGirlById(Integer id);
@Select("SELECT * FROM girl")
List<Girl> findAll();
@Insert("INSERT INTO girl VALUES(NULL,#{age},#{name})")
int addGirl(Girl girl);
@Update("UPDATE girl SET age = #{girl.age},name = #{girl.name} WHERE id = #{id}")
int updateGirl(@Param("id") Integer id, @Param("girl") Girl girl);
@Delete("DELETE FROM girl WHERE id = #{id}")
int deleteGirl(Integer id);
}
以上注解的使用基本与之前xml中的用法一致，完整注解，参考官网：http://www.mybatis.org/mybatis-3/zh/java-api.html
当然，需要注意的是，mybatis官网给出了使用注解的注意点：
不幸的是,Java 注解限制了它们的表现和灵活。尽管很多时间都花调查,设计和 实验上,最强大的 MyBatis 映射不能用注解来构建,那并不可笑。
4.测试
启动类：
package com.example.demo;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
// @MapperScan("cn.demo.mapper") 若Mapper上不加注解，则在这里统一扫描
public class SpringbootDemoApplication {
public static void main(String[] args) {
SpringApplication.run(SpringbootDemoApplication.class, args);
}
}
controller：
@GetMapping(value = "/girl/{id}")
public Girl findGirlById(@PathVariable("id") Integer id) {
return girlService.findGirlById(id);
}
@PutMapping(value = "/girl/{id}")
public Integer updateGirlById(@PathVariable("id") Integer id, Girl girl) {
return girlService.updateGirl(id, girl);
}
package com.example.demo.controller; import com.example.demo.bean.Girl; import com.example.demo.bean.Result; import com.example.demo.dao.GirlRepository; import com.example.demo.service.GirlService; import com.example.demo.utils.ResultUtils; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.validation.BindingResult; import org.springframework.validation.FieldError; import org.springframework.web.bind.annotation.*; import javax.validation.Valid; import java.util.List; /** * controller * * @author zcc ON 2018/2/9 **/ @RestController public class GirlController { /** * 简单的逻辑，这里就暂时省略service了 */ private static final Logger log = LoggerFactory.getLogger(GirlController.class); @Autowired private GirlRepository girlRepository; @Autowired private GirlService girlService; @GetMapping(value = "/girls") public List<Girl> getList() { // 直接调用findAll()即可，已经封装了！ return girlRepository.findAll(); } /** * 可以使用此方式进行参数绑定 */ /*@PostMapping(value = "/girls") public String addGirl(@RequestParam("age") Integer age, String name) { return null; }*/ /** * 更推荐bean进行绑定（这里规则和springMVC是一样的） * @param girl 实体 * @return */ @PostMapping(value = "/girls") public Result<Object> addGirl(@Valid Girl girl, BindingResult bindingResult) { // 表单验证逻辑 if (bindingResult.hasErrors()) { List<FieldError> fieldErrors = bindingResult.getFieldErrors(); StringBuffer sb = new StringBuffer(); for (FieldError fieldError : fieldErrors) { sb.append(fieldError.getDefaultMessage()); } return ResultUtils.error(sb.toString()); } return ResultUtils.success(girlRepository.save(girl)); } @GetMapping(value = "/girls/{id}") public Girl getGirlById(@PathVariable("id") Integer id) { // 推荐使用更加通用的findOne()! return girlRepository.findOne(id); } @PutMapping(value = "/girls/{id}") public Girl updateGirlById(@PathVariable("id") Integer id, String name) { Girl girl = new Girl(); girl.setId(id); girl.setName(name); return girlRepository.save(girl); } @DeleteMapping(value = "/girls/{id}") public String deleteGirlById(@PathVariable("id") Integer id) { girlRepository.delete(id); return "删除ID为：" + id + " 的女生成功！"; } @GetMapping(value = "/girls/age/{age}") public List<Girl> getListByAge(@PathVariable("age") Integer age) { return girlRepository.findByAge(age); } @PostMapping(value = "/girls/two") public void insertTwo() { girlService.insertTwo(); } @GetMapping(value = "/girls/getAge/{id}") public void getAge(@PathVariable("id") Integer id) { // 判断应该交给service girlService.getAge(id); } @GetMapping(value = "/ageAndId/{name}/{id}") public List<Girl> testKeyWords(@PathVariable("name") String name, @PathVariable("id") Integer id) { return girlService.findByNameStartingWithAndIdLessThan(name, id); } @GetMapping(value = "/girl/{id}") public Girl findGirlById(@PathVariable("id") Integer id) { return girlService.findGirlById(id); } @PutMapping(value = "/girl/{id}") public Integer updateGirlById(@PathVariable("id") Integer id, Girl girl) { return girlService.updateGirl(id, girl); } }
service：
public Girl findGirlById(Integer id) {
return girlMapper.findGirlById(id);
}
public int updateGirl(Integer id, Girl girl) {
return girlMapper.updateGirl(id, girl);
}
package com.example.demo.service; import com.example.demo.dao.GirlRepository; import com.example.demo.bean.Girl; import com.example.demo.enums.ResultEnum; import com.example.demo.exception.MyException; import com.example.demo.mapper.GirlMapper; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Service; import org.springframework.transaction.annotation.Transactional; import java.util.List; /** * service * * @author zcc ON 2018/2/9 **/ @Service public class GirlService { @Autowired private GirlRepository girlRepository; @Autowired private GirlMapper girlMapper; @Transactional public void insertTwo() { Girl girl1 = new Girl("Nana", 18); Girl girl2 = new Girl("Lala", 19); girlRepository.save(girl1); girlRepository.save(girl2); } public void getAge(Integer id) { Integer age = girlRepository.findOne(id).getAge(); if (age < 12) { // 小学生 throw new MyException(ResultEnum.PRIMARY); } else { // 上初中了 throw new MyException(ResultEnum.MIDDLE); } } /** * 通过id查询 * @param id 实体类id * @return */ public Girl findOne(Integer id) { return girlRepository.findOne(id); } public List<Girl> findByNameStartingWithAndIdLessThan(String name, Integer id) { return girlRepository.findByNameStartingWithAndIdLessThan(name, id); } public Girl findGirlById(Integer id) { return girlMapper.findGirlById(id); } public int updateGirl(Integer id, Girl girl) { return girlMapper.updateGirl(id, girl); } }
注入mapper报错的处理（不影响实际使用，强迫症可选）
实际测试可以使用经典的postman，也推荐IDEA自带的tool——REST Client
三、经典注解版
基本代码类似，只是少数代码更改
项目结构：
yml配置mybatis：
mybatis:
type-aliases-package: com.example.demo.bean
mapper-locations: classpath:mybatis/mapper/*.xml
config-location: classpath:mybatis/mybatis-config.xml
// 别名也可以在mybatis-config.xml中进行配置！，默认别名参考文档：点击查看
mybatis-config.xml：
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
<typeAliases>
</typeAliases>
</configuration>
mapper：
package com.example.demo.mapper;
import com.example.demo.bean.Girl;
import org.apache.ibatis.annotations.Param;
import java.util.List;
/**
* GirlMapper
*
* @author zcc
**/
// 这里不在这里加@Repository注解，统一在启动类通过MapperScan扫描
public interface GirlMapper {
Girl findGirlById(Integer id);
List<Girl> findAll();
int addGirl(Girl girl);
int updateGirl(@Param("id") Integer id, @Param("girl") Girl girl);
int deleteGirl(Integer id);
}
mapper.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接口代理实现编写规则：
1.映射文件中namespace要等于接口的全路径
2.映射文件中sql语句的id要等于接口的方法名
3.映射文件中传入参数类型要等于接口方法的入参
4.映射文件返回值类型要等于接方法的返回值类型
-->
<mapper namespace="com.example.demo.mapper.GirlMapper">
<resultMap id="BaseResultMap" type="girl">
<id column="id" property="id" jdbcType="INTEGER"/>
<result column="age" property="age" jdbcType="INTEGER"/>
<result column="name" property="name" jdbcType="VARCHAR"/>
</resultMap>
<sql id="Base_Column_List">
id,age,name
</sql>
<select id="findGirlById" parameterType="integer" resultMap="BaseResultMap">
SELECT
<include refid="Base_Column_List"/>
FROM girl
WHERE id = #{id}
</select>
<select id="findAll" resultMap="BaseResultMap">
SELECT
<include refid="Base_Column_List"/>
FROM girl
</select>
<select id="addGirl" parameterType="girl">
INSERT INTO
girl(age,name)
VALUES(#{age},#{name})
</select>
<update id="updateGirl" parameterType="girl">
UPDATE
girl
SET
age = #{age},name = #{name}
WHERE
id = #{id}
</update>
<delete id="deleteGirl" parameterType="integer">
DELETE
FROM
girl
WHERE
id = #{id}
</delete>
</mapper>
mapper中的各种警告处理（不影响使用，强迫症可以进行设置）：
