springboot整合Mybatis（一）——入門

一、概述

　　1.先導

　　　　mybatis入門隨筆：http://www.cnblogs.com/jiangbei/p/6884641.html

　　2.引入依賴

　　　　　　　<dependency>
           　　 <groupId>org.mybatis.spring.boot</groupId>
          　　  <artifactId>mybatis-spring-boot-starter</artifactId>
          　　  <version>1.3.0</version>
            </dependency>

　　　　//其他必須的依賴還包括mysql連接，web依賴（web項目），此處貼出完整依賴（有部分依賴例如jpa此處可不選）

<?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 來支持 JPA-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <!-- mysql連接-->
        <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連接池 -->
        <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熱部署支持-->
        <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熱部署 -->
                   <!-- <dependency>
                        <groupId>org.springframework</groupId>
                        <artifactId>springloaded</artifactId>
                        <version>1.2.6.RELEASE</version>
                    </dependency>-->
                </dependencies>
            </plugin>
        </plugins>
    </build>


</project>

　

　　額外功能（后文陸續補充）

• • 　　PageHelper 分頁插件
  • 　　mybatis generator 自動生成代碼插件

　　　3.數據源配置

　　　　依舊是前文的druid數據源

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配置項，默認spring-boot不支持，故需要config類來解析
    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

　　　　以下介紹兩種整合方式：

　　　　　　傳統的mapper.xml映射文件

　　　　　　springboot提倡的無配置注解形式

二、無配置注解形式

　　1.配置mybatis：

mybatis: type-aliases-package: com.example.demo.bean

// 包別名簡寫

　　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 = "名稱長度不合法！")
    private String name;
    @Min(value = 18, message = "未成年禁止入內！")
    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 這里可以使用@Mapper注解，但是每個mapper都加注解比較麻煩，所以也可以統一配置@MapperScan在掃描路徑在application類中
@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與之前xml中的用法一致，完整注解，參考官網：http://www.mybatis.org/mybatis-3/zh/java-api.html

 　　當然，需要注意的是，mybatis官網給出了使用注解的注意點：

不幸的是,Java 注解限制了它們的表現和靈活。盡管很多時間都花調查,設計和 實驗上,最強大的 MyBatis 映射不能用注解來構建,那並不可笑。

　　4.測試

　　　　啟動類：

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，則在這里統一掃描
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 {
    /**
     * 簡單的邏輯，這里就暫時省略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() {
        // 直接調用findAll()即可，已經封裝了！
        return girlRepository.findAll();
    }

    /**
     * 可以使用此方式進行參數綁定
     */
    /*@PostMapping(value = "/girls")
    public String addGirl(@RequestParam("age") Integer age, String name) {
        return null;
    }*/

    /**
     * 更推薦bean進行綁定（這里規則和springMVC是一樣的）
     * @param girl 實體
     * @return
     */
    @PostMapping(value = "/girls")
    public Result<Object> addGirl(@Valid Girl girl, BindingResult bindingResult) {
        // 表單驗證邏輯
        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) {
        // 推薦使用更加通用的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 "刪除ID為：" + 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) {
        // 判斷應該交給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) {
            // 小學生
            throw new MyException(ResultEnum.PRIMARY);
        } else {
            // 上初中了
            throw new MyException(ResultEnum.MIDDLE);
        }
    }

    /**
     * 通過id查詢
     * @param id 實體類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報錯的處理（不影響實際使用，強迫症可選）

 

　　實際測試可以使用經典的postman，也推薦IDEA自帶的tool——REST Client

三、經典注解版

　　基本代碼類似，只是少數代碼更改

　　項目結構：

　　　　

　　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

　　// 別名也可以在mybatis-config.xml中進行配置！，默認別名參考文檔：點擊查看

　　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 **/
// 這里不在這里加@Repository注解，統一在啟動類通過MapperScan掃描
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接口代理實現編寫規則： 1.映射文件中namespace要等於接口的全路徑 2.映射文件中sql語句的id要等於接口的方法名 3.映射文件中傳入參數類型要等於接口方法的入參 4.映射文件返回值類型要等於接方法的返回值類型 -->
<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中的各種警告處理（不影響使用，強迫症可以進行設置）：