Spring Boot：Spring Boot配置Mybatis

1. maven引入依赖

<!-- 数据库连接池-->
      <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>${druid.version}</version>
        </dependency>

        <!-- mybatis 依赖-->
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>${mybatis-spring-boot.version}</version>
        </dependency>

        <!-- jdbc支持-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jdbc</artifactId>
        </dependency>

        <!-- mysql驱动 -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>${mysql-connector-java.version}</version>
        </dependency>

2. 设置Druid数据源

添加SingleDataSourceConfig.java配置文件,整合Druid数据源

/**
 * 数据源配置
 * @Auther: hrabbit
 * @Date: 2018-12-19 11:18 AM
 * @Description:
 */
@Configuration
@MapperScan({"com.hrabbit.admin.modual.system.mapper"})
public class SingleDataSourceConfig {

    /**
     * Druid配置
     */
    @Bean
    @ConfigurationProperties(prefix = "spring.datasource")
    public DruidProperties druidProperties() {
        return new DruidProperties();
    }
}

其中的DruidProperties.java的配置信息如下(这里使用了Lombok,因此省略了get/set方法，不了解Lombok的童鞋请搜索下):

/**
 * 数据库数据源配置
 * @author hrabbit
 * @date 2018-11-21 11:18
 */
@Component
@ConfigurationProperties(prefix = "spring.datasource")
@Data
public class DruidProperties {

    private String url = "jdbc:mysql://127.0.0.1:3306/guns?autoReconnect=true&useUnicode=true&characterEncoding=utf8&zeroDateTimeBehavior=convertToNull";

    private String username = "root";

    private String password = "root";

    private String driverClassName = "com.mysql.jdbc.Driver";

    private Integer initialSize = 2;

    private Integer minIdle = 1;

    private Integer maxActive = 20;

    private Integer maxWait = 60000;

    private Integer timeBetweenEvictionRunsMillis = 60000;

    private Integer minEvictableIdleTimeMillis = 300000;

    private String validationQuery = "SELECT 'x'";

    private Boolean testWhileIdle = true;

    private Boolean testOnBorrow = false;

    private Boolean testOnReturn = false;

    private Boolean poolPreparedStatements = true;

    private Integer maxPoolPreparedStatementPerConnectionSize = 20;

    private String filters = "stat";

    public void config(DruidDataSource dataSource) {

        dataSource.setUrl(url);
        dataSource.setUsername(username);
        dataSource.setPassword(password);

        dataSource.setDriverClassName(driverClassName);
        dataSource.setInitialSize(initialSize);     //定义初始连接数
        dataSource.setMinIdle(minIdle);             //最小空闲
        dataSource.setMaxActive(maxActive);         //定义最大连接数
        dataSource.setMaxWait(maxWait);             //最长等待时间

        // 配置间隔多久才进行一次检测，检测需要关闭的空闲连接，单位是毫秒
        dataSource.setTimeBetweenEvictionRunsMillis(timeBetweenEvictionRunsMillis);

        // 配置一个连接在池中最小生存的时间，单位是毫秒
        dataSource.setMinEvictableIdleTimeMillis(minEvictableIdleTimeMillis);
        dataSource.setValidationQuery(validationQuery);
        dataSource.setTestWhileIdle(testWhileIdle);
        dataSource.setTestOnBorrow(testOnBorrow);
        dataSource.setTestOnReturn(testOnReturn);

        // 打开PSCache，并且指定每个连接上PSCache的大小
        dataSource.setPoolPreparedStatements(poolPreparedStatements);
        dataSource.setMaxPoolPreparedStatementPerConnectionSize(maxPoolPreparedStatementPerConnectionSize);

        try {
            dataSource.setFilters(filters);
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}

3.配置application.yml文件中的mapper.xml的存放路径

### 启动端口号
server:
  port: 8080
### 设置数据库
spring:
  datasource:
    url: jdbc:mysql://127.0.0.1:3306/hrabbit_admin?autoReconnect=true&useUnicode=true&characterEncoding=utf8&zeroDateTimeBehavior=convertToNull&useSSL=false
    username: root
    password: root
### 配置Mybatis
mybatis:
  ### xml存放路径
  mapper-locations: classpath:mapper/*Mapper.xml

mapper.xml的路径resources/mapper/*.Mapper.xml如下：

4. 创建SysUserMapper.java 的接口：

创建一个根据id查询的接口:

/**
 * 系统用户数据库层
 * @Auther: hrabbit
 * @Date: 2018-12-19 12:02 PM
 * @Description:
 */
public interface SysUserMapper {

    /**
     * 根据id查询用户信息
     * @param id
     * @return
     */
    SysUser findSysUserById(@Param("id") Long id);
}

5. 在SysUserMapper.xml编写sql语句：

<?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="com.hrabbit.admin.modual.system.mapper.SysUserMapper">
    <!--
        根据用户id获取角色信息
    -->
    <select id="findSysUserById" resultType="com.hrabbit.admin.modual.system.bean.SysUser">
        select * from sys_user where id=#{id};
    </select>
</mapper>

6. 启动项目，在Postman访问获取用户信息的接口:

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