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Spring+Mybatis实现动态SQL查询

2019-05-27 09:58 459 查看
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在报表类应用中,通常需要根据不同的维度去组合复杂的查询条件,然后构造SQL去执行查询。如果只是通过在程序中简单地拼接SQL语句,工作量会非常大,而且代码可能也非常难以维护。Mybatis支持动态SQL查询功能,可以通过配置动态的SQL来简化程序代码中复杂性,通过XML来处理复杂的数据判断、循环的功能,其实也很好理解。

**

  • 准备工作

**

下面,我们首先创建一个MySQL示例表,如下所示:

CREATE TABLE `traffic_info` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`domain` varchar(64) NOT NULL,
`traffic_host` varchar(64) NOT NULL,
`month` varchar(8) NOT NULL,
`monthly_traffic` int(11) DEFAULT '0',
`global_traffic_rank` int(11) DEFAULT '0',
`native_traffic_rank` int(11) DEFAULT '0',
`rank_in_country` varchar(64) DEFAULT NULL,
`address` varchar(200) DEFAULT NULL,
`email` varchar(50) DEFAULT NULL,
`traffic_type` int(2) DEFAULT '-1',
`status` int(2) DEFAULT '0',
`created_at` date DEFAULT NULL,
`updated_at` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
`f1` varchar(255) DEFAULT NULL,
`f2` varchar(255) DEFAULT NULL,
`f3` varchar(255) DEFAULT NULL,
PRIMARY KEY (`id`),
UNIQUE KEY `idx_traffic` (`domain`,`month`,`traffic_type`)
) ENGINE=MyISAM AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;

这个表用来存储域名的流量信息,流量信息我们从互联网上像Alexa、Compete、Quantcast等提供商获取,通过Crawler抓取的方式实现。我们先从简单的查询做起,只是根据某个字段进行查询,说明如何配置使用Mybatis,这里面也包含如何与Spring进行集成。

**

  • 配置实践

**

下面是用到的一些资源的定义:
org.shirdrn.mybatis.TrafficInfo类

该类对应于traffic_info表中一条记录的数据,我们简单取几个字段,如下所示:

package org.shirdrn.mybatis;

import java.io.Serializable;

public class TrafficInfo implements Serializable {

private static final long serialVersionUID = -8696613205078899594L;
int id;
String domain;
String month;
int monthlyTraffic;

public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getDomain() {
return domain;
}
public void setDomain(String domain) {
this.domain = domain;
}
public String getMonth() {
return month;
}
public void setMonth(String month) {
this.month = month;
}
public int getMonthlyTraffic() {
return monthlyTraffic;
}
public void setMonthlyTraffic(int monthlyTraffic) {
this.monthlyTraffic = monthlyTraffic;
}

@Override
public String toString() {
return "[id=" + id + ", domain=" + domain + ", month=" +
month + ", monthlyTraffic=" + monthlyTraffic + "]";
}

}

org.shirdrn.mybatis.mapper.TrafficInfoMapper接口类

该类定义了一个与SQL配置进行映射的基本操作,实际的SQL配置有专门的XML文件来进行配置。该接口定义了如下操作:

package org.shirdrn.mybatis.mapper;

import java.util.List;
import java.util.Map;

import org.shirdrn.mybatis.TrafficInfo;

public interface TrafficInfoMapper {

/**
* 根据指定id去查询记录,结果至多只有一条
* @param id
* @return
*/
TrafficInfo getTrafficInfo(int id);

/**
* 根据指定的domain参数查询记录,返回一个记录的列表
* @param domain
* @return
*/
List<TrafficInfo> getTrafficInfoList(String domain);

/**
* 根据一个 字段domain进行查询,但是存在多个domain的值,传入一个数组
* @param domains
* @return
*/
List<TrafficInfo> getMultiConditionsList(String[] domains);

/**
* 根据多个字段进行查询,每个字段可能有多个值,所以参数是Map类型
* @param conditions
* @return
*/
List<TrafficInfo> getMapConditionsList(Map<String, Object> conditions);

}

上面接口中定义的操作,一个比一个复杂,我们通过这一系列操作来说明在Mybatis中如果使用各种查询功能。

org/shirdrn/mybatis/mapper/TrafficInfoMapper.xml映射配置文件
这个文件TrafficInfoMapper.xml对应了上面的org.shirdrn.mybatis.mapper.TrafficInfoMapper中定义的操作,通过XML的方式将对应的SQL查询构造出来,这个是Mybatis的核心功能。该文件的内容示例如下所示:

<?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.shirdrn.mybatis.mapper.TrafficInfoMapper">
<resultMap type="TrafficInfo" id="tfMap">
<id property="id" column="id" />
<result property="domain" column="domain" />
<result property="month" column="month" />
<result property="monthlyTraffic" column="monthlyTraffic" />
</resultMap>

<select id="getTrafficInfo" resultType="TrafficInfo" parameterType="int">
SELECT * FROM domain_db.traffic_info WHERE id = #{id}
</select>

<select id="getTrafficInfoList" resultType="TrafficInfo" parameterType="string">
SELECT * FROM domain_db.traffic_info WHERE domain = #{domain}
</select>

<select id="getMultiConditionsList" resultMap="tfMap">
SELECT * FROM domain_db.traffic_info WHERE domain IN
<foreach collection="array" index="index" item="domain" open=" (" separator="," close=")">
#{domain}
</foreach>
</select>

<select id="getMapConditionsList" resultMap="tfMap">
SELECT * FROM domain_db.traffic_info WHERE domain IN
<foreach collection="domains" index="index" item="domain" open=" (" separator="," close=")">
#{domain}
</foreach>
AND status = 0 AND month IN
<foreach collection="months" index="index" item="month" open=" (" separator="," close=")">
#{month}
</foreach>
</select>

</mapper>

如果你之前用过ibatis,应该很熟悉上面这个配置文件。上面:
namespace指定该SQL映射配置文件的Mapper接口类,其中定义了基本的SQL查询操作(以我们给出的例子为例);
resultMap中的type的值这里是一个别名,当然也可以使用对应的具体类全名(包名+类名),我们会在Mybatis的总的映射配置文件中进行配置,详见后面说明;
select是查询SQL的配置,可以通过不同的元素进行动态构造,如if、foreach等;

Mybatis全局映射配置文件sqlMapConfig.xml
该文件可以指定数据库连接池配置、别名配置、SQL映射配置文件组等内容,这里示例的配置内容如下所示:

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-config.dtd">

<configuration>
<typeAliases>
<typeAlias type="org.shirdrn.mybatis.TrafficInfo" alias="TrafficInfo" />
</typeAliases>
<mappers>
<mapper resource="org/shirdrn/mybatis/mapper/TrafficInfoMapper.xml" />
</mappers>
</configuration>

Spring配置文件applicationContext.xml

<?xml version="1.0" encoding="UTF-8"?>

<bean
class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
<property name="systemPropertiesModeName" value="SYSTEM_PROPERTIES_MODE_OVERRIDE" />
<property name="ignoreResourceNotFound" value="true" />
<property name="locations">
<list>
<value>classpath*:/proxool.properties</value>
</list>
</property>
</bean>

<context:component-scan base-package="org.shirdrn.mybatis" />

<aop:aspectj-autoproxy proxy-target-class="true" />
<aop:config proxy-target-class="true" />

<bean id="dataSource" class="org.shirdrn.mybatis.utils.ProxoolDataSource">
<property name="driver" value="${jdbc-0.proxool.driver-class}" />
<property name="driverUrl" value="${jdbc-0.proxool.driver-url}" />
<property name="user" value="${jdbc-0.user}" />
<property name="password" value="${jdbc-0.password}" />
<property name="alias" value="${jdbc-0.proxool.alias}" />
<property name="prototypeCount" value="${jdbc-0.proxool.prototype-count}" />
<property name="maximumActiveTime" value="${jdbc-0.proxool.maximum-active-time}" />
<property name="maximumConnectionCount" value="${jdbc-0.proxool.maximum-connection-count}" />
<property name="minimumConnectionCount" value="${jdbc-0.proxool.minimum-connection-count}" />
<property name="simultaneousBuildThrottle"
value="${jdbc-0.proxool.simultaneous-build-throttle}" />
<property name="verbose" value="${jdbc-0.proxool.verbose}" />
<property name="trace" value="${jdbc-0.proxool.trace}" />
<property name="houseKeepingTestSql" value="${jdbc-0.proxool.house-keeping-test-sql}" />
<property name="houseKeepingSleepTime" value="${jdbc-0.proxool.house-keeping-sleep-time}" />
<property name="maximumConnectionLifetime"
value="${jdbc-0.proxool.maximum-connection-lifetime}" />
</bean>

<bean id="dataSource0" class="org.jdbcdslog.ConnectionPoolDataSourceProxy">
<property name="targetDSDirect" ref="dataSource" />
</bean>

<!-- http://mybatis.github.io/spring/getting-started.html -->
<!-- http://mybatis.github.io/spring/zh/ -->
<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
<property name="dataSource" ref="dataSource0" />
<property name="configLocation" value="classpath:sqlMapConfig.xml"/>
</bean>
<bean id="trafficInfoMapper" class="org.mybatis.spring.mapper.MapperFactoryBean">
<property name="mapperInterface" value="org.shirdrn.mybatis.mapper.TrafficInfoMapper" />
<property name="sqlSessionFactory" ref="sqlSessionFactory" />
</bean>
<bean id="trafficInfoService" class="org.shirdrn.mybatis.TrafficInfoService">
<property name="trafficInfoMapper" ref="trafficInfoMapper" />
</bean>

说明一下:
dataSource使用的Proxool连接池组件;
sqlSessionFactory是Mybatis的SessionFactory,注入了前面获取到的dataSource,同时指定了Mybatis的总的映射配置文件classpath:sqlMapConfig.xml,属性名为configLocation;
trafficInfoMapper直接由Spring的org.mybatis.spring.mapper.MapperFactoryBean进行代理,需要注入属性mapperInterface(即我们定义的SQL Mapper操作的接口类)和sqlSessionFactory(前面的SessionFactory实例);
trafficInfoService是我们最终在其中进行调用的服务类,注入了我们定义的SQL Mapper接口类的实例trafficInfoMapper。

org.shirdrn.mybatis.TrafficInfoService服务类
为简单起见,我们就不定义服务接口了,直接在该类中实现,调用SQL Mapper中预定义的SQL查询操作,实现代码如下所示:

package org.shirdrn.mybatis;

import java.util.List;
import java.util.Map;

import org.shirdrn.mybatis.mapper.TrafficInfoMapper;

public class TrafficInfoService {

private TrafficInfoMapper trafficInfoMapper;

public void setTrafficInfoMapper(TrafficInfoMapper trafficInfoMapper) {
this.trafficInfoMapper = trafficInfoMapper;
}

public TrafficInfo getTrafficInfo(int id) {
return trafficInfoMapper.getTrafficInfo(id);
}

public List<TrafficInfo> getTrafficInfoList(String domain) {
return trafficInfoMapper.getTrafficInfoList(domain);
}

public List<TrafficInfo> getMultiConditionsList(String[] domains) {
return trafficInfoMapper.getMultiConditionsList(domains);
}

List<TrafficInfo> getMapConditionsList(Map<String, Object> conditions) {
return trafficInfoMapper.getMapConditionsList(conditions);
}

}

按照上面的配置,我们就能够实现从单个字段的查询,到多个字段的组合复杂查询。可以通过与实际编写代码来控制这些逻辑相比较,使用Mybatis可能配置上相对复杂一些,但是或得到的好处是非常多的,如代码可维护性好,看起来配置比较直观,出错的几率会大大减小。实际上,如果熟练的这种配置方式,就会在实际开发过程中,更好地去处理更加复杂的统计查询条件的组合逻辑。

**

  • 测试用例

**

测试用例可以检测我们上面的配置是否生效,实现代码:

package org.shirdrn.mybatis;

import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = { "classpath:/applicationContext*.xml" })
public class TestTrafficInfoService {

@Autowired
private TrafficInfoService trafficInfoService;

@Test
public void getTraffic() {
int id = 1196;
TrafficInfo result = trafficInfoService.getTrafficInfo(id);
System.out.println(result);
}

@Test
public void getTrafficList() {
String domain = "make-the-cut.com";
List<TrafficInfo> results = trafficInfoService.getTrafficInfoList(domain);
System.out.println(results);
}

@Test
public void getMultiConditionsList() {
String[] domains = new String[] {
"make.tv", " make-the-cut.com", "makgrills.com", "makino.com"
};
List<TrafficInfo> results = trafficInfoService.getMultiConditionsList(domains);
System.out.println(results);
}

@Test
public void getMapConditionsList() {
String[] domains = new String[] {
"make.tv", " make-the-cut.com", "makgrills.com", "makino.com"
};
List<String> months = Arrays.asList(new String[] {
"201203", "201204", "201205"
});
Map<String, Object> conditions = new HashMap<String, Object>(2);
conditions.put("domains", domains);
conditions.put("months", months);
List<TrafficInfo> results = trafficInfoService.getMapConditionsList(conditions);
System.out.println(results);
}

}

**

  • 查询进阶

**

这里,给出一个实际的例子,是对每日报表的一个统计实例,为简单起见,只拿出2张表做LEFT JOIN连接。这个需求,要求查询时可以对每个维度取过得查询条件值,如对于维度osName,值可以使包含Android、IOS,对于另一个维度statDate,可以取最近2天(昨天和前天),等等,并且,这些组合条件可有可无。
对应的Mybatis映射配置文件,内容如下所示:

<?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.shirdrn.data.mappers.DailyAppUserMapper">
<resultMap id="dailyAppUserMap" type="DailyAppUser">
<id property="id" column="id" />
<result property="primaryCategoryId" column="primary_category_id" />
<result property="primaryCategoryName" column="primary_category_name" />
<result property="secondaryCategoryId" column="secondary_category_id" />
<result property="secondaryCategoryName" column="secondary_category_name" />
<result property="cooperationMode" column="cooperation_mode" />
<result property="merchantId" column="merchant_id" />
<result property="merchantName" column="merchant_name" />
<result property="osName" column="osName" />
<result property="channelId" column="channel_id" />
<result property="channelName" column="channel_name" />
<result property="version" column="version" />
<result property="statDate" column="stat_date" />
<result property="newUserOpen" column="new_user_open" />
<result property="activeUserOpen" column="active_user_open" />
<result property="activeUserPlay" column="active_user_play" />
<result property="oldUserOpen" column="old_user_open" />
<result property="oldUserPlay" column="old_user_play" />
<result property="averageTime" column="average_time" />
<result property="newUserAverageTime" column="new_user_average_time" />
<result property="oldUserAverageTime" column="old_user_average_time" />
<result property="newUserOpen2Retention" column="new_user_open_2retention" />
<result property="newUserOpen3Retention" column="new_user_open_3retention" />
<result property="newUserOpen7Retention" column="new_user_open_7retention" />
<result property="newUserOpen15Retention" column="new_user_open_15retention" />
<result property="newUserOpen30Retention" column="new_user_open_30retention" />
</resultMap>

<select id="getDailyAppUserListByPage" resultMap="dailyAppUserMap">
<include refid="getDailyAppUserList"/>
LIMIT #{offset}, #{limit}
</select>

<select id="getDailyAppUserListForReport" resultMap="dailyAppUserMap">
<include refid="getDailyAppUserList"/>
</select>

<sql id="getDailyAppUserList" >
SELECT
d.id AS id,
d.primary_category_id AS primary_category_id,
d.primary_category_name AS primary_category_name,
d.secondary_category_id AS secondary_category_id,
d.secondary_category_name AS secondary_category_name,
d.cooperation_mode AS cooperation_mode,
d.merchant_id AS merchant_id,
d.osName AS osName,
d.channel_id AS channel_id,
(CASE WHEN d.channel_name IS NOT NULL THEN d.channel_name ELSE d.channel_id END) AS channel_name,
d.version AS version,
d.stat_date AS stat_date,
d.new_user_open AS new_user_open,
d.new_user_play AS new_user_play,
d.active_user_open AS active_user_open,
d.active_user_play AS active_user_play,
d.old_user_open AS old_user_open,
d.old_user_play AS old_user_play,
d.average_time AS average_time,
d.new_user_average_time AS new_user_average_time,
d.old_user_average_time AS old_user_average_time,
d.new_user_open_2retention AS new_user_open_2retention,
d.new_user_open_3retention AS new_user_open_3retention,
d.new_user_open_7retention AS new_user_open_7retention,
d.new_user_open_15retention AS new_user_open_15retention,
d.new_user_open_30retention AS new_user_open_30retention,
d.uninstall_cnt AS uninstall_cnt,
m.merchant_name AS merchant_name
FROM daily_app_user d
LEFT JOIN merchant m ON d.merchant_id=m.id
WHERE d.stat_date = #{statDate}
<if test="osNames!=null">
AND d.osName IN
<foreach collection="osNames" index="index" item="osName" open=" (" separator="," close=")">
#{osName}
</foreach>
</if>
<if test="channelNames!=null">
AND
<foreach collection="channelNames" index="index" item="channelName" open=" (" separator=" OR " close=")">
(d.channel_name LIKE CONCAT('%', CONCAT(#{channelName}, '%')))
</foreach>
</if>
<if test="versions!=null">
AND d.version IN
<foreach collection="versions" index="index" item="version" open=" (" separator="," close=")">
#{version}
</foreach>
</if>
<if test="merchantNames!=null">
AND
<foreach collection="merchantNames" index="index" item="merchantName" open=" (" separator=" OR " close=")">
(m.merchant_name LIKE CONCAT('%', CONCAT(#{%merchantName%}, '%')))
</foreach>
</if>
<if test="primaryCategories!=null">
AND d.primary_category_id IN
<foreach collection="primaryCategories" index="index" item="primaryCategory" open=" (" separator="," close=")">
#{primaryCategory}
</foreach>
</if>
<if test="secondaryCategories!=null">
AND d.secondary_category_id IN
<foreach collection="secondaryCategories" index="index" item="secondaryCategory" open=" (" separator="," close=")">
#{secondaryCategory}
</foreach>
</if>
<if test="cooperationModes!=null">
AND d.cooperation_model IN
<foreach collection="cooperationModes" index="index" item="cooperationMode" open=" (" separator="," close=")">
#{cooperationMode}
</foreach>
</if>
</sql>

</mapper>

上述映射配置对应的Mapper定义,接口如下所示:

package org.shirdrn.data.mappers;

import java.util.List;
import java.util.Map;

import org.shirdrn.data.beans.DailyAppUser;

public class DailyAppUserMapper {

List<DailyAppUser> getDailyAppUserListByPage(Map<String, Object> conditions);
List<DailyAppUser> getDailyAppUserListForReport(Map<String, Object> conditions);
}

需要说明的是,如果多个表,一定要设置好Mapper映射配置中每个select元素的resultMap属性,属性值就是前部分的resultMap定义的id。如果只从单个表查询数据,完全可以使用resultType,对应resultMap元素中配置的type属性所指定的别名。
实际上,我们需要通过Map来传递参数,也就是把查询的条件值都收集起来,然后放到Map中,示例如下:

Map<String, Object> conditions = new HashMap<String, Object>();
if(osNames != null) {
conditions.put(DailyAppUserMapper.KEY_OS_NAMES, osNames);
}
if(channelNames != null) {
conditions.put(DailyAppUserMapper.KEY_CHANNEL_NAMES, channelNames);
}
if(versions != null) {
conditions.put(DailyAppUserMapper.KEY_VERSIONS, versions);
}
if(merchantNames != null) {
conditions.put(DailyAppUserMapper.KEY_MERCHANT_NAMES, merchantNames);
}
if(primaryCategories != null) {
conditions.put(DailyAppUserMapper.KEY_PRIMARY_CATEGORIES, primaryCategories);
}
if(secondaryCategories != null) {
conditions.put(DailyAppUserMapper.KEY_SECONDARY_CATEGORIES, secondaryCategories);
}
if(cooperationModes != null) {
conditions.put(ChannelDayMapper.KEY_COOPERATION_MODES, cooperationModes);
}

上面对应的DailyAppUserMapper中定义的一些Key常量名称,要和Mapper配置文件中foreach元素的collection属性值一致。

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