[Java知识库]SpringBoot第 2 讲：SpringBoot集成MyBatis

本案例所使用到的IDE

jdk1.8、MySQL5.7

一、新建Maven项目

请参考我关于SpringBoot教程的第一讲内容：

https://blog.csdn.net/qzc70919700/article/details/119574690

二、配置pom.xml文件

2.1、将以下内容替换到pom.xml文件中

<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>1.5.2.RELEASE</version>
	</parent>

	<groupId>cn.personal.qin.demo</groupId>
	<artifactId>springboot_demo</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<packaging>war</packaging>

	<name>springboot</name>
	<url>http://maven.apache.org</url>

	<properties>
		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
		<!-- java版本 -->
		<java.version>1.8</java.version>
	</properties>

	<dependencies>
		<dependency>
			<groupId>junit</groupId>
			<artifactId>junit</artifactId>
			<scope>test</scope>
		</dependency>
		<!-- 添加springMVC支持 -->
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>
		</dependency>
		<!-- MySQL -->
		<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>1.3.2</version>
		</dependency>
		<dependency>
			<groupId>org.mybatis</groupId>
			<artifactId>mybatis-spring</artifactId>
			<version>1.3.1</version>
		</dependency>
		<dependency>
			<groupId>org.mybatis</groupId>
			<artifactId>mybatis</artifactId>
			<version>3.5.0</version>
		</dependency>
		<!-- dbcp连接池 <dependency> <groupId>commons-dbcp</groupId> <artifactId>commons-dbcp</artifactId> 
			<version>1.4</version> </dependency> -->
		<!-- 连接池 -->
		<dependency>
			<groupId>com.jolbox</groupId>
			<artifactId>bonecp-spring</artifactId>
			<version>0.8.0.RELEASE</version>
		</dependency>
		<!-- spring核心 -->
		<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-tx</artifactId>
		</dependency>
		<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-jdbc</artifactId>
		</dependency>
		<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-aspects</artifactId>
		</dependency>
		<!-- Begin##添加JSP支持##Begin -->
		<dependency>
			<groupId>org.apache.tomcat.embed</groupId>
			<artifactId>tomcat-embed-jasper</artifactId>
			<scope>provided</scope>
		</dependency>
		<!-- End##添加JSP支持##Begin -->
	</dependencies>

	<build>
		<finalName>${project.artifactId}</finalName>
		<plugins>
			<!-- 资源文件拷贝插件 -->
			<plugin>
				<groupId>org.apache.maven.plugins</groupId>
				<artifactId>maven-resources-plugin</artifactId>
				<configuration>
					<encoding>UTF-8</encoding>
				</configuration>
			</plugin>
			<!-- java编译插件 -->
			<plugin>
				<groupId>org.apache.maven.plugins</groupId>
				<artifactId>maven-compiler-plugin</artifactId>
				<configuration>
					<source>1.7</source>
					<target>1.7</target>
					<encoding>UTF-8</encoding>
				</configuration>
			</plugin>
			<!-- Begin##03、添加SpringBoot的插件支持##Begin -->
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
			</plugin>
			<!-- End##03、添加SpringBoot的插件支持##End -->
		</plugins>
		<pluginManagement>
			<plugins>
				<!-- 配置Tomcat插件 -->
				<plugin>
					<groupId>org.apache.tomcat.maven</groupId>
					<artifactId>tomcat7-maven-plugin</artifactId>
					<version>2.2</version>
				</plugin>
			</plugins>
		</pluginManagement>
	</build>
</project>

2.2、更新Maven下载jar包

项目鼠标右键-->Maven-->Update Project...

三、项目开发

3.1、项目文件结构

请下载项目源代码，并将配置文件拷贝到src/main/resources文件夹中

?3.2、配置MyBatis

3.2.1、MyBatis目录配置类Cast

Cast.java类的作用是用于配置MyBatis中配置文件及mapper、po的位置

package org.personal.qin.demo.config;

public class Cast {
	//配置MyBatis
	public static final String MYBATIS_CONFIG = "classpath:mybatis-config.xml";
	public static final String PO_PACKAGE = "org.personal.qin.demo.po";
	public static final String MAPPER_PACKAGE = "org.personal.qin.demo.mapper";
	public static final String MAPPER_SCANNER = "classpath:config/mapper/*.xml";

}

3.2.2、MyBatis加载配置文件及配置数据源MyBatisConfig

MyBatisConfig.java类的作用是加载MyBatis配置文件，并配置数据源

package org.personal.qin.demo.config;

import javax.sql.DataSource;

import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.boot.autoconfigure.SpringBootVFS;
import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.io.Resource;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.core.io.support.ResourcePatternResolver;

@Configuration
public class MyBatisConfig {
	
    /**
     * ConditionalOnMissingBean当容器里没有指定的Bean的情况下创建该对象
     */
    @Bean
    @ConditionalOnMissingBean
    public SqlSessionFactory sqlSessionFactoryBean(DataSource dataSource) throws Exception {
        SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
        // 设置数据源
        sqlSessionFactoryBean.setDataSource(dataSource);
        // 添加一行如下代码,解决setTypeAliasesPackage别名设置不起作用问题
        sqlSessionFactoryBean.setVfs(SpringBootVFS.class);
        //设置mybatis的主配置文件
        ResourcePatternResolver resourceResolver = new PathMatchingResourcePatternResolver();
		Resource mybatisConfigXml = resourceResolver.getResource(Cast.MYBATIS_CONFIG);
		sqlSessionFactoryBean.setConfigLocation(mybatisConfigXml);
		// 设置别名包
        sqlSessionFactoryBean.setTypeAliasesPackage(Cast.PO_PACKAGE);
        PathMatchingResourcePatternResolver resolver = new PathMatchingResourcePatternResolver();
        sqlSessionFactoryBean.setMapperLocations(resolver.getResources(Cast.MAPPER_SCANNER));
        return sqlSessionFactoryBean.getObject();
    }

}

3.2.3、Mapper扫描MapperScannerConfig

MapperScannerConfig.java类的作用是扫描Mapper

package org.personal.qin.demo.config;

import org.mybatis.spring.mapper.MapperScannerConfigurer;
import org.springframework.boot.autoconfigure.AutoConfigureAfter;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

/**
 * 保证在MybatisConfig类实例化后才实例化此方法
 */
@Configuration
@AutoConfigureAfter(MyBatisConfig.class)
public class MapperScannerConfig {
	
    /**
     * mapper接口的扫描器
     * 
     * @return
     */
    @Bean
    public MapperScannerConfigurer mapperScannerConfigurer() {
        MapperScannerConfigurer mapperScannerConfigurer = new MapperScannerConfigurer();
        mapperScannerConfigurer.setBasePackage(Cast.MAPPER_PACKAGE);
        return mapperScannerConfigurer;
    }

}

3.3、配置SpringBoot

BootApplication.java文件的作用是配置SpringBoot，并加载jdbc配置文件，配置数据库及数据库连接池，MainApplication.java提供了main方法，是该程序的入口以供程序运行

package org.personal.qin.demo.config;

import javax.sql.DataSource;

import com.jolbox.bonecp.BoneCPDataSource;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.builder.SpringApplicationBuilder;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.PropertySource;

/**
 * 配置文件读取和扫描
 */
@Configuration
@PropertySource(value = { "classpath:jdbc.properties" })
@ComponentScan(basePackages = "org.personal.qin.demo")
@SpringBootApplication
public class BootApplication {

	@Value("${jdbc.driver}")
	private String driverClassName; // 数据库驱动

	@Value("${jdbc.url}")
	private String url; // 相应驱动的jdbcUrl

	@Value("${jdbc.username}")
	private String username; // 数据库的用户名

	@Value("${jdbc.password}")
	private String password; // 数据库的密码
	
	@Value("${jdbc.period_in_minutes}")
	private int periodInMinutes; // 检查数据库连接池中空闲连接的间隔时间，单位是分，默认值：240，如果要取消则设置为0
	
	@Value("${jdbc.max_age_in_minutes}")
	private int maxAgeInMinutes; // 连接池中未使用的链接最大存活时间，单位是分，默认值：60，如果要永远存活设置为0
	
	@Value("${jdbc.max_connections_per_partition}")
	private int maxConnectionsPerPartition; // 每个分区最大的连接数
	
	@Value("${jdbc.min_connections_per_partition}")
	private int minConnectionsPerPartition; // 每个分区最小的连接数

	/**
	 * 配置数据源
	 * 
	 * @return
	 */
	@Bean(destroyMethod = "close")
	public DataSource dataSource() {
		BoneCPDataSource boneCPDataSource = new BoneCPDataSource();
        boneCPDataSource.setDriverClass(driverClassName);
        boneCPDataSource.setJdbcUrl(url);
        boneCPDataSource.setUsername(username);
        boneCPDataSource.setPassword(password);
        boneCPDataSource.setIdleConnectionTestPeriodInMinutes(periodInMinutes);
        boneCPDataSource.setIdleMaxAgeInMinutes(maxAgeInMinutes);
        boneCPDataSource.setMaxConnectionsPerPartition(maxConnectionsPerPartition);
        boneCPDataSource.setMinConnectionsPerPartition(minConnectionsPerPartition);
        return boneCPDataSource;
	}

	protected SpringApplicationBuilder springApplicationBuilder(SpringApplicationBuilder builder) {
		return builder.sources(BootApplication.class);
	}

}

package org.personal.qin.demo;

import org.personal.qin.demo.config.BootApplication;
import org.springframework.boot.SpringApplication;

/**
 * 项目工程入口
 */
public class MainApplication {

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

}

3.4、开始业务层代码

开始编写业务层代码Po、Mapper、Controller

3.4.1、Po

User.java是Pojo

package org.personal.qin.demo.po;

public class User {

	private int id;
	private String name;
	private String password;

	public int getId() {
		return id;
	}

	public void setId(int id) {
		this.id = id;
	}

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public String getPassword() {
		return password;
	}

	public void setPassword(String password) {
		this.password = password;
	}

	@Override
	public String toString() {
		return "【User】: name=" + name + ", password=" + password;
	}

}

3.4.2、Mapper

UserMapper.java是Mapper接口，UserMapper.xml是操作数据库的配置文件

package org.personal.qin.demo.mapper;

import java.util.List;

import org.personal.qin.demo.po.User;

public interface UserMapper {

    /**
     * 获取全部用户
     * 
     * @return
     */
    List<User> listAll();

}

<?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 namespace="org.personal.qin.demo.mapper.UserMapper">
	<select id="listAll" resultType="User">
		select * from t_user
	</select>
</mapper>

3.4.3、Controller

UserController.java是控制器，提供给web访问

package org.personal.qin.demo.controller;

import java.util.List;

import org.personal.qin.demo.mapper.UserMapper;
import org.personal.qin.demo.po.User;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

@Controller
public class UserController {

    @Autowired
    private UserMapper mapper;

    @RequestMapping("/users")
    @ResponseBody
    public Object getAllUser() {
        List<User> users = mapper.listAll();
        return users;
    }

}

四、浏览器测试

运行MainApplication.java中的main方法

浏览器中访问UserController的/users映射：http://127.0.0.1:8080/users

?成功从数据库中读取到了数据，并以json的格式显示在了网页上

五、项目源代码及数据库脚本

https://download.csdn.net/download/qzc70919700/20970559???????