SpringBoot整合mybatis

摘要：SpringBoot遵循约定大于配置的原则，整合mybatis只需要简单配置即可使用。

首先，新建SpringBoot工程，并引入相关依赖。包含mybatis、connector、druid
maven依赖如下：

<?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.test</groupId>
  <artifactId>SpringBoot-mybatis</artifactId>
  <version>0.0.1-SNAPSHOT</version>

  <name>SpringBoot-mybatis</name>
  <url>http://www.example.com</url>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <maven.compiler.source>1.8</maven.compiler.source>
    <maven.compiler.target>1.8</maven.compiler.target>
  </properties>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.1.RELEASE</version>
    </parent>

  <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.mybatis.spring.boot</groupId>
        <artifactId>mybatis-spring-boot-starter</artifactId>
        <version>1.3.1</version>
    </dependency>
    <dependency>                
        <groupId>com.alibaba</groupId>                
        <artifactId>druid</artifactId>                
        <version>1.0.9</version>            
    </dependency>
   <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
    </dependency>
  </dependencies>
  <build>
        <plugins>
            <plugin>
                <groupId>org.mybatis.generator</groupId>
                <artifactId>mybatis-generator-maven-plugin</artifactId>
                <version>1.3.2</version>
                <configuration>
                    <!-- mybatis用于生成代码的配置文件 -->
                    <configurationFile>src/main/resources/generatorConfig.xml</configurationFile>
                    <verbose>true</verbose>
                    <overwrite>true</overwrite>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

搭建项目结构，创建存放controller、model、mapper的包，及配置文件，如图：

项目结构

配置文件：

application.yml，配置数据库及连接池信息：

server:
  port: 9310

spring:
  application:
    name: contract-server
  datasource:
    name: test
    url: jdbc:mysql://127.0.0.1:3306/'dataName'
    username: root
    password: admin
    # 使用druid数据源
    type: com.alibaba.druid.pool.DruidDataSource
    driver-class-name: com.mysql.jdbc.Driver
    filters: stat
    maxActive: 20
    initialSize: 1
    maxWait: 60000
    minIdle: 1
    timeBetweenEvictionRunsMillis: 60000
    minEvictableIdleTimeMillis: 300000
    validationQuery: select 'x'
    testWhileIdle: true
    testOnBorrow: false
    testOnReturn: false
    poolPreparedStatements: true
    maxOpenPreparedStatements: 20

application.properties文件，

配置扫描xml位置及model位置，虽然可用注解写sql，但xml相对更灵活，如动态sql，字段映射等

#对象位置
mybatis.type-aliases-package=com.test.model
#xml文件位置
mybatis.mapper-locations=classpath:mybatis/mapper/*.xml

可使用generator根据数据库自动生成代码

配置如下：

<?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>
    <classPathEntry location="D:/01_Work/repository/mysql/mysql-connector-java/5.1.46/mysql-connector-java-5.1.46.jar" />
    <context id="MysqlContext" targetRuntime="MyBatis3" defaultModelType="flat">
        <property name="beginningDelimiter" value="`"/>
        <property name="endingDelimiter" value="`"/>

        <commentGenerator>
        <!--         阻止生成注释 -->
            <property name="suppressAllComments" value="true"/>
        <!--         阻止生成时间戳 -->
            <property name="suppressDate" value="true"/>
        </commentGenerator>
        <!--    数据库配置    -->
        <jdbcConnection driverClass="com.mysql.jdbc.Driver"
                        connectionURL="jdbc:mysql://localhost:3306/datebaseName"
                        userId="root"
                        password="admin">
        </jdbcConnection>

        <javaModelGenerator targetPackage="com.test.model" targetProject="./src/main/java">
            <property name="trimStrings" value="true" />
            <property name="enableSubPackages" value="true" />
        </javaModelGenerator>

        <sqlMapGenerator targetPackage="mybatis/mapper"  targetProject="./src/main/resources">
        <property name="enableSubPackages" value="true" />
        </sqlMapGenerator>

        <javaClientGenerator type="XMLMAPPER" targetPackage="com.test.mybatis.mapper"  targetProject="./src/main/java"/>

        <table tableName="contract" domainObjectName="Contract">
            <generatedKey column="id" sqlStatement="Mysql" identity="true" />
        </table>
    </context>
</generatorConfiguration>

generator详细配置：https://blog.csdn.net/xp_lx1/article/details/80074738
现在使用maven插件自动生成model、mapper、及xml文件.

数据库建表并录入数据

data

插件已在maven中引入，右击工程>>run as>>maven build>>
执行:mybatis-generator:generate

执行generateor

success

刷新项目：

标准四件套

现在我们可以写controller代码：


@RestController
public class TestController {
    //注入mapper
    @Autowired
    ContractMapper contractmapper;
    
    @RequestMapping("getList")
    public List<Contract> getList(){
        List<Contract> contractList = contractmapper.selectByExample(null);
        return contractList;
    }
}

创建启动类并启动项目：

@SpringBootApplication
//此处增加扫描注解
@MapperScan("com.test.mybatis")
public class App 
{
    public static void main( String[] args )
    {
        SpringApplication.run(App.class, args);
    }
}

浏览器输入：http://127.0.0.1:9310/getList

得到结果：

result