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>

pom.xml　

　　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

application.yml

　　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 +
                '}';
    }
}

Girl.java

　　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);
    }
}

controller

　　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);
    }
}

service

　　　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）：