Springboot集成Mybatis，采用druid数据源及mysql数据库为例

1、  添加Maven依赖：

<!--springboot对数据库类的支持 -->

<dependency>

<groupId>org.mybatis.spring.boot</groupId>

<artifactId>mybatis-spring-boot-starter</artifactId>

<version>1.3.0</version>

</dependency>

<dependency>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter-data-jpa</artifactId>

</dependency>

<dependency>

<groupId>mysql</groupId>

<artifactId>mysql-connector-java</artifactId>

</dependency>

<dependency>

<groupId>com.alibaba</groupId>

<artifactId>druid</artifactId>

<version>1.0.31</version>

</dependency>

2、  修改application.properties文件或application.yml文件：

spring:  datasource:    url: jdbc:mysql://localhost:3306/test    username: root    password: root123    driver-class-name: com.mysql.jdbc.Driver    type: com.alibaba.druid.pool.DruidDataSource    initialSize: 5    minIdle: 5    maxActive: 20    maxWait: 60000    timeBetweenEvictionRunsMillis: 60000    minEvictableIdleTimeMillis: 300000    validationQuery: SELECT 1    testWhileIdle: true    testOnBorrow: false    testOnReturn: false    poolPreparedStatements: true    maxPoolPreparedStatementPerConnectionSize: 20    filters: stat,wall,log4j    connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=5000    mybatis:  config-location: classpath:mybatis-config.xml  mapperLocations: classpath:mybatis/mapper/*.xml

3、  添加DruidConfig.java配置数据源，因为Springboot内置的数据源不是Druid，所以要手动添加一个这样的配置类。

package com.demo.common.db;import java.sql.SQLException;import javax.sql.DataSource;import org.slf4j.Logger;import org.slf4j.LoggerFactory;import org.springframework.beans.factory.annotation.Value;import org.springframework.boot.web.servlet.FilterRegistrationBean;import org.springframework.boot.web.servlet.ServletRegistrationBean;import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Configuration;import org.springframework.context.annotation.Primary;import com.alibaba.druid.pool.DruidDataSource;import com.alibaba.druid.support.http.StatViewServlet;import com.alibaba.druid.support.http.WebStatFilter;@Configurationpublic class DruidConfig {private Logger logger = LoggerFactory.getLogger(getClass());@Value("${spring.datasource.url}")private String dbUrl;@Value("${spring.datasource.username}")private String username;@Value("${spring.datasource.password}")private String password;@Value("${spring.datasource.driver-class-name}")private String driverClassName;@Value("${spring.datasource.initialSize}")private int initialSize;@Value("${spring.datasource.minIdle}")private int minIdle;@Value("${spring.datasource.maxActive}")private int maxActive;@Value("${spring.datasource.maxWait}")private int maxWait;@Value("${spring.datasource.timeBetweenEvictionRunsMillis}")private int timeBetweenEvictionRunsMillis;@Value("${spring.datasource.minEvictableIdleTimeMillis}")private int minEvictableIdleTimeMillis;@Value("${spring.datasource.validationQuery}")private String validationQuery;@Value("${spring.datasource.testWhileIdle}")private boolean testWhileIdle;@Value("${spring.datasource.testOnBorrow}")private boolean testOnBorrow;@Value("${spring.datasource.testOnReturn}")private boolean testOnReturn;@Value("${spring.datasource.poolPreparedStatements}")private boolean poolPreparedStatements;@Value("${spring.datasource.filters}")private String filters;@Beanpublic ServletRegistrationBean druidServlet() {ServletRegistrationBean reg = new ServletRegistrationBean();reg.setServlet(new StatViewServlet());reg.addUrlMappings("/druid/*");reg.addInitParameter("loginUsername", "druid");reg.addInitParameter("loginPassword", "jiajian123456");return reg;}@Beanpublic FilterRegistrationBean filterRegistrationBean() {FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean();filterRegistrationBean.setFilter(new WebStatFilter());filterRegistrationBean.addUrlPatterns("/*");filterRegistrationBean.addInitParameter("exclusions", "*.js,*.gif,*.jpg,*.png,*.css,*.ico,/druid/*");filterRegistrationBean.addInitParameter("profileEnable", "true");filterRegistrationBean.addInitParameter("principalCookieName", "USER_COOKIE");filterRegistrationBean.addInitParameter("principalSessionName", "USER_SESSION");return filterRegistrationBean;}@Bean // 声明其为Bean实例@Primary // 在同样的DataSource中，首先使用被标注的DataSourcepublic DataSource druidDataSource() {DruidDataSource datasource = new DruidDataSource();datasource.setUrl(this.dbUrl);datasource.setUsername(username);datasource.setPassword(password);datasource.setDriverClassName(driverClassName);datasource.setInitialSize(initialSize);datasource.setMinIdle(minIdle);datasource.setMaxActive(maxActive);datasource.setMaxWait(maxWait);datasource.setTimeBetweenEvictionRunsMillis(timeBetweenEvictionRunsMillis);datasource.setMinEvictableIdleTimeMillis(minEvictableIdleTimeMillis);datasource.setValidationQuery(validationQuery);datasource.setTestWhileIdle(testWhileIdle);datasource.setTestOnBorrow(testOnBorrow);datasource.setTestOnReturn(testOnReturn);datasource.setPoolPreparedStatements(poolPreparedStatements);try {datasource.setFilters(filters);} catch (SQLException e) {logger.error("druid configuration initialization filter", e);}return datasource;}}

4、自动配置模式：

添加一个Dao接口UserMapper.java：

package com.demo.dao;import java.util.List;import org.apache.ibatis.annotations.Mapper;import org.apache.ibatis.annotations.Select;import com.demo.entity.User;@Mapperpublic interface UserMapper {@Select("select *from t_user")List getAllUser();User getUserById(Integer id);}

其中getAllUser方法就是自动配置方式，无需其他任何配置既可查询数据，@Mapper是Mybatis的注解方法，查询数据绑定全靠它。

5、采用Mybatis推荐的XML模式，创建xml文件：

mybatis-config.xml：

UserMapper.xml：

select * from t_userwhere id=#{id}

其中getUserById即对应UserMapper.java中的getUserById方法