spring-boot 速成(8) 集成druid+mybatis

spring-boot与druid、mybatis集成（包括pageHelper分页插件）, 要添加以下几个依赖项:

    compile('mysql:mysql-connector-java:6.0.5')
    compile('tk.mybatis:mapper-spring-boot-starter:1.1.1')
    compile('org.mybatis.spring.boot:mybatis-spring-boot-starter:1.3.0')
    compile('com.github.pagehelper:pagehelper-spring-boot-starter:1.1.1')
    compile('com.alibaba:druid:1.0.28')

一、集成druid

1.1 编写自定义属性类

package com.cnblogs.yjmyzz.druid;

import lombok.Data;
import org.springframework.boot.context.properties.ConfigurationProperties;

@ConfigurationProperties(prefix = "druid")
@Data
public class DruidProperties {
    private String url;
    private String username;
    private String password;
    private String driverClass;

    private int maxActive;
    private int minIdle;
    private int initialSize;
    private boolean testOnBorrow;
}

注：这里只列出了主要属性，其它属性如果需要，可自行添加

1.2 创建自定义配置类

package com.cnblogs.yjmyzz.druid;

import com.alibaba.druid.pool.DruidDataSource;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.autoconfigure.AutoConfigureBefore;
import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
import org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import javax.sql.DataSource;
import java.sql.SQLException;

@Configuration
@EnableConfigurationProperties(DruidProperties.class)
@ConditionalOnClass(DruidDataSource.class)
@ConditionalOnProperty(prefix = "druid", name = "url")
@AutoConfigureBefore(DataSourceAutoConfiguration.class)
public class DruidAutoConfiguration {

    @Autowired
    private DruidProperties properties;

    @Bean
    public DataSource dataSource() {
        DruidDataSource dataSource = new DruidDataSource();
        dataSource.setUrl(properties.getUrl());
        dataSource.setUsername(properties.getUsername());
        dataSource.setPassword(properties.getPassword());
        if (properties.getInitialSize() > 0) {
            dataSource.setInitialSize(properties.getInitialSize());
        }
        if (properties.getMinIdle() > 0) {
            dataSource.setMinIdle(properties.getMinIdle());
        }
        if (properties.getMaxActive() > 0) {
            dataSource.setMaxActive(properties.getMaxActive());
        }
        dataSource.setTestOnBorrow(properties.isTestOnBorrow());
        try {
            dataSource.init();
        } catch (SQLException e) {
            throw new RuntimeException(e);
        }
        return dataSource;
    }
}　　

注1：如果多数据源的，参考上面的代码自行修改

注2：上面这二个类，可以抽出来放到公用类库里，方便以后复用。　

1.3 添加 META-INF/spring.factories

参考如下内容（告诉spring-boot，如何自动加载配置)

# Auto Configure
org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
com.cnblogs.yjmyzz.druid.DruidAutoConfiguration

1.4 application.yml中配置

druid:
    url: jdbc:mysql://localhost:3306/study?useSSL=false
    driver-class: com.mysql.jdbc.Driver
    username: root
    password: ***
    initial-size: 1
    min-idle: 1
    max-active: 20
    test-on-borrow: true

二、集成mybatis

2.1 常规的mapper/xml配置

这个跟常规使用mybatis并没有什么不同，参考上图的结构

2.2 抽象一个通用Mapper

package com.cnblogs.yjmyzz.util;

import tk.mybatis.mapper.common.Mapper;
import tk.mybatis.mapper.common.MySqlMapper;

public interface MyMapper<T> extends Mapper<T>, MySqlMapper<T> {

}

写这个通用Mapper是为了后面写crud代码更简单，其它具体的XXXMapper都应该继承它，类似：

package com.cnblogs.yjmyzz.dao.mapper;

import com.cnblogs.yjmyzz.dao.model.City;
import com.cnblogs.yjmyzz.util.MyMapper;

public interface CityMapper extends MyMapper<City> {
}

2.3 application.yml配置

mybatis:
    type-aliases-package: com.cnblogs.yjmyzz.service.dao
    mapper-locations: classpath:mapper/*.xml

mapper:
    mappers:
        - com.cnblogs.yjmyzz.util.MyMapper
    not-empty: false
    identity: MYSQL

pagehelper:
    helperDialect: mysql
    reasonable: true
    supportMethodsArguments: true
    params: count=countSql

还有一个常见问题：如何在调试时输出SQL语句，以及屏蔽掉一些不需要的日志？可参考下面的配置

logging:
    level:
        root: DEBUG
        tk.mybatis: DEBUG
        com.alibaba.dubbo: ERROR
        org.apache.zookeeper: ERROR
    file: "/var/log/application/dubbo-provider.log"

最后使用的地方，代码就跟常规代码完全一样了，参考下面：

package com.cnblogs.yjmyzz.service.impl;

import com.alibaba.dubbo.config.annotation.Service;
import com.cnblogs.yjmyzz.dao.mapper.CityMapper;
import com.cnblogs.yjmyzz.dao.model.City;
import com.cnblogs.yjmyzz.service.api.DemoService;
import com.cnblogs.yjmyzz.service.api.vo.CityVO;
import com.github.pagehelper.PageHelper;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.util.CollectionUtils;

import java.util.ArrayList;
import java.util.List;

/**
 * Created by 菩提树下的杨过(http:/yjmyzz.cnblogs.com) on 2017/5/21.
 */
@Service(version = "1.0.0")
public class DemoServiceImpl implements DemoService {

    Logger logger = LoggerFactory.getLogger(DemoServiceImpl.class);

    @Autowired
    CityMapper cityMapper;

    @Override
    public List<CityVO> getCityList(int pageIndex, int pageSize) {
        PageHelper.startPage(pageIndex, pageSize);//设置分页参数
        List<City> list = cityMapper.selectAll();
        com.github.pagehelper.PageInfo page = new com.github.pagehelper.PageInfo<>(list);//取页面信息
        List<CityVO> result = new ArrayList<>();
        if (!CollectionUtils.isEmpty(list)) {
            for (City c : list) {
                CityVO v = new CityVO();
                v.setCityName(c.getName());
                v.setProvinceName(c.getState());
                result.add(v);
            }
        }
        logger.info("pageInfo=> page:" + page.getPageNum() + "/" + page.getPages());
        return result;
    }

}

文中的示例代码，已经托管在github上，地址：https://github.com/yjmyzz/spring-boot-dubbo-demo