Spring Boot整合MyBatis（使用Spring Tool Suite工具）

1. 创建Spring Boot项目

通过Spring Tool Suite的Spring Starter Project对话框，其实是把项目生成的工作委托http://start.spring.io上的Spring Initializr来做的，因此必须联网才能使用这一功能。

1.1 解决创建Spring Boot项目时遇到的问题

右键项目 --> Java EE Tools --> Generate Deployment Descriptor Stub

Help --> Install New SoftWare


https://otto.takari.io/content/sites/m2e.extras/m2eclipse-mavenarchiver/0.17.2/N/LATEST/
安装完成后就重启Spring Tool Suite，然后右键项目Maven --> Update Project。

2. 编写配置文件

package com.example.demo;

import org.springframework.boot.builder.SpringApplicationBuilder;
import org.springframework.boot.web.servlet.support.SpringBootServletInitializer;

public class ServletInitializer extends SpringBootServletInitializer {

	@Override
	protected SpringApplicationBuilder configure(SpringApplicationBuilder application) {
		return application.sources(DemoApplication.class);
	}

}

package com.example.demo;

import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
//import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.ComponentScan;

import com.alibaba.druid.spring.boot.autoconfigure.DruidDataSourceAutoConfigure;

@SpringBootApplication(exclude={DruidDataSourceAutoConfigure.class})
//@EnableAutoConfiguration(exclude={DruidDataSourceAutoConfigure.class})
@ComponentScan(basePackages="com.example")
@MapperScan(basePackages="com.example.mapper")
public class DemoApplication {

	public static void main(String[] args) {
		SpringApplication.run(DemoApplication.class, args);
	}

}

//我们需要类似于web.xml的配置方式来启动spring上下文了，在Application类的同级添加一个SpringBootStartApplication类
//参考：https://blog.csdn.net/liupantao/article/details/74942833
package com.example.demo;

import org.springframework.boot.builder.SpringApplicationBuilder;
import org.springframework.boot.web.servlet.support.SpringBootServletInitializer;

public class SpringBootStartApplication extends SpringBootServletInitializer {

	@Override
	protected SpringApplicationBuilder configure(SpringApplicationBuilder builder) {
		return builder.sources(DemoApplication.class);
	}
	
}

我们删除src/main/resources目录下的application.properties文件，新建一个application.yml文件。
相关阅读：Spring Boot的 yml和properties的对比

# application.yml
server:
  port: 8080
  servlet:
   context-path: /demo

spring:
  mvc:
    view:
      prefix: /WEB-INF/views/
      suffix: .jsp
  datasource:
    type: com.alibaba.druid.pool.DruidDataSource
    driver-class-name: com.mysql.jdbc.Driver
    url: jdbc:mysql://localhost:3306/demosql?useSSL=false
    username: root
    password: root
    
mybatis:
  config-location: classpath:mybatis-config.xml
  mapper-locations: classpath:mapping/*.xml
  type-aliases-package: com.example.entity

2.1 MyBatis自动生成代码

参考：Mybatis Generator最完整配置详解
在pom.xml文件中配置一下mybatis-generator-maven-plugin即可。

<?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>
	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>2.1.1.RELEASE</version>
		<relativePath/> <!-- lookup parent from repository -->
	</parent>
	<groupId>com.example</groupId>
	<artifactId>demo</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<packaging>war</packaging>
	<name>demo</name>
	<description>Demo project for Spring Boot</description>

	<properties>
		<java.version>1.8</java.version>
	</properties>

	<dependencies>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>
			<!-- 打包的时候以war包形式，这里要把springboot集成的tomcat去除 -->
			<exclusions>
				<exclusion>
					<groupId>org.springframework.boot</groupId>
					<artifactId>spring-boot-starter-tomcat</artifactId>
				</exclusion>
			</exclusions>
		</dependency>
		<dependency>
			<groupId>org.mybatis.spring.boot</groupId>
			<artifactId>mybatis-spring-boot-starter</artifactId>
			<version>1.3.2</version>
		</dependency>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-tomcat</artifactId>
			<scope>provided</scope>
		</dependency>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-test</artifactId>
			<scope>test</scope>
		</dependency>
		
		<!-- mysql -->
		<dependency>
		    <groupId>mysql</groupId>
		    <artifactId>mysql-connector-java</artifactId>
		    <version>5.1.38</version><!--$NO-MVN-MAN-VER$-->
		</dependency>
		
		<!-- alibaba的druid数据库连接池 -->
		<dependency>
			<groupId>com.alibaba</groupId>
			<artifactId>druid-spring-boot-starter</artifactId>
			<version>1.1.0</version>
		</dependency>
		
		<!-- 热部署模块 -->
		<dependency>
		    <groupId>org.springframework.boot</groupId>
		    <artifactId>spring-boot-devtools</artifactId>
		    <optional>true</optional> <!-- 这个需要为 true 热部署才有效 -->
		</dependency>
	</dependencies>

	<build>
		<finalName>demo</finalName>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
			</plugin>
			<!-- mybatis generator 自动生成代码插件 -->
			<plugin>
				<groupId>org.mybatis.generator</groupId>
				<artifactId>mybatis-generator-maven-plugin</artifactId>
				<version>1.3.2</version>
				<configuration>
					<configurationFile>${basedir}/src/main/resources/generator/generatorConfig.xml</configurationFile>
					<overwrite>true</overwrite>
					<verbose>true</verbose>
				</configuration>
			</plugin>
		</plugins>
	</build>

</project>

<!-- generatorConfig.xml -->
<?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>
    <!-- 数据库驱动:选择你的本地硬盘上面的数据库驱动包-->
    <classPathEntry  location="E:RepMavenmysqlmysql-connector-java5.1.38mysql-connector-java-5.1.38.jar"/>
    <context id="mysql"  targetRuntime="MyBatis3">
        <!--数据库链接URL，用户名、密码 -->
        <jdbcConnection driverClass="com.mysql.jdbc.Driver" connectionURL="jdbc:mysql:///demosql" userId="root" password="root">
        </jdbcConnection>
        <javaTypeResolver>
            <property name="forceBigDecimals" value="false"/>
        </javaTypeResolver>
        <!-- 生成模型的包名和位置-->
        <javaModelGenerator targetPackage="com.example.entity" targetProject="src/main/java">
            <property name="enableSubPackages" value="true"/>
            <property name="trimStrings" value="true"/>
        </javaModelGenerator>
        <!-- 生成映射文件的包名和位置-->
        <sqlMapGenerator targetPackage="com.example.mapper.mapping" targetProject="src/main/java">
            <property name="enableSubPackages" value="true"/>
        </sqlMapGenerator>
        <!-- 生成DAO的包名和位置-->
        <javaClientGenerator type="XMLMAPPER" targetPackage="com.example.mapper" targetProject="src/main/java">
            <property name="enableSubPackages" value="true"/>
        </javaClientGenerator>
        <!-- 要生成的表 tableName是数据库中的表名或视图名 domainObjectName是实体类名-->
        <table tableName="t_user" domainObjectName="User" enableCountByExample="false" enableUpdateByExample="false" enableDeleteByExample="false" enableSelectByExample="false" selectByExampleQueryId="false"></table>
    </context>
</generatorConfiguration>

创建数据库和表（手动创建- -）。

执行mybatis-generator:generate命令即可。

3. 编写源码以及启动项目

package com.example.controller;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

import com.example.entity.User;
import com.example.service.UserService;

@RequestMapping("/hjj")
@Controller
public class UserController {
	@Autowired
	private UserService userService;

	@RequestMapping("test")
	public String test(){
		return "test";
	}
	
	@ResponseBody
	@RequestMapping("/getUserById/{id}")
	public User getUserById(@PathVariable("id")Integer id){
		return userService.getUserById(id);
	}
}

package com.example.service;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import com.example.entity.User;
import com.example.mapper.UserMapper;

@Service
public class UserService {

	@Autowired
	private UserMapper userMapper;
	
	public User getUserById(Integer id){
		return userMapper.selectByPrimaryKey(id);
	}
}

将项目放到Tomcat就可以启动运行了。

注意：Maven打包项目时，在src/main/java目录下的Java文件会被编译成class文件，而其他类型的文件会被忽略。
下载源码：https://pan.baidu.com/s/1uTapGFlPpKnrmwVA6woKGg 提取码：9wsn