pagehelper 联表 分页查询性能优化 -- (sql允许先分页,后联表)
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优化的前提条件,分页的sql允许先分页,联表并不影响最后的结果集,只是补齐所需字段信息.
一,pagehelper改造思路
1,5.0.0以上版本支持手动count查询语句.详见 https://github.com/pagehelper/Mybatis-PageHelper/
2,自定义拦截器,对有别名为"AS limitable" 的子查询sql进行sql拼接,将 本应拼接到末尾的limit ?,? 拼接到子查询sql末尾.
3,重新定位入参的位置.将limit的参数从末尾调整到limit子查询语句的地方.
4,用法,同pagehelper正常用法(版本要求5.0.4以上), 将pagehelper拦截器配置为自定义拦截器.
二,代码部分
1,mapper
<!-- 分页条件查询 优化 -->
<select id="findUserCount" resultMap="BaseResultMap">
select limitable.openId as openId,
insert(limitable.mobile,4,4,'****') AS mobile,
limitable.subscribeTime as subscribeTime,
limitable.unSubscribeTime as unSubscribeTime,
c.chanelName as chanelName
from
(select countBind.bindChannelId,countBind.openId,
countBind.mobile,countBind.subscribeTime,
countBind.unSubscribeTime,countBind.userTag
FROM countBind
WHERE
countBind.countId = #{countId,jdbcType=INTEGER}
<if
test="userCountReq.unSubendTime != null and userCountReq.unSubendTime !=''">
and countBind.unSubscribeTime <= #{userCountReq.unSubendTime}
</if>
<if
test="userCountReq.bindChannelIds != null and userCountReq.bindChannelIds.size()>0">
and countBind.bindChannelId in
<foreach collection="userCountReq.bindChannelIds" index="index"
item="idItem" open="(" separator="," close=")">
#{idItem}
</foreach>
</if>
<if test="userCountReq.tags != null and userCountReq.tags.size()>0">
and countBind.userTag in
<foreach collection="userCountReq.tags" index="index" item="tagItem"
open="(" separator="," close=")">
#{tagItem}
</foreach>
</if>
) AS limitable
left join
channel c
on
limitable.bindChannelId=c.channelId
where
c.countId = #{countId,jdbcType=INTEGER}
</select>
<!-- 分页条件统计Count 优化-->
<select id="findUserCount_COUNT" resultType="java.lang.Integer">
select count(*)
from
countBind b
where
b.countId = #{countId,jdbcType=INTEGER}
<if
test="userCountReq.unSubendTime != null and userCountReq.unSubendTime !=''">
and b.unSubscribeTime <= #{userCountReq.unSubendTime}
</if>
<if
test="userCountReq.bindChannelIds != null and userCountReq.bindChannelIds.size()>0">
and b.bindChannelId in
<foreach collection="userCountReq.bindChannelIds" index="index"
item="idItem" open="(" separator="," close=")">
#{idItem}
</foreach>
</if>
<if test="userCountReq.tags != null and userCountReq.tags.size()>0">
and b.userTag in
<foreach collection="userCountReq.tags" index="index" item="tagItem"
open="(" separator="," close=")">
#{tagItem}
</foreach>
</if>
</select>2 pagehelper拦截器
/* * The MIT License (MIT)
* * Copyright (c) 2014-2017 abel533@gmail.com
* * Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
* * The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
* * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
import java.lang.reflect.Field;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.Properties;
import org.apache.ibatis.cache.CacheKey;
import org.apache.ibatis.executor.Executor;
import org.apache.ibatis.mapping.BoundSql;
import org.apache.ibatis.mapping.MappedStatement;
import org.apache.ibatis.mapping.ParameterMapping;
import org.apache.ibatis.plugin.Interceptor;
import org.apache.ibatis.plugin.Intercepts;
import org.apache.ibatis.plugin.Invocation;
import org.apache.ibatis.plugin.Plugin;
import org.apache.ibatis.plugin.Signature;
import org.apache.ibatis.session.Configuration;
import org.apache.ibatis.session.ResultHandler;
import org.apache.ibatis.session.RowBounds;
import com.github.pagehelper.Dialect;
import com.github.pagehelper.PageException;
import com.github.pagehelper.cache.Cache;
import com.github.pagehelper.cache.CacheFactory;
import com.github.pagehelper.util.MSUtils;
import com.github.pagehelper.util.StringUtil;
/** * 对pagehelper联表分页查询进行sql优化.(待优化sql的前提条件.可以先分页后联表) ,指定标识符"AS limitable"
* 为分页标识的sql. 末尾带有 AS limitable 的子查询会拼接上limit进行先分页.然后再外联查询
* * @author mumu/liuzh/abel533/isea533
* @version 5.0.0
*/
@SuppressWarnings({ "rawtypes", "unchecked" })
@Intercepts({
@Signature(type = Executor.class, method = "query", args = { MappedStatement.class, Object.class,
RowBounds.class, ResultHandler.class }),
@Signature(type = Executor.class, method = "query", args = { MappedStatement.class, Object.class,
RowBounds.class, ResultHandler.class, CacheKey.class, BoundSql.class }), })
public class MumuPageInterceptor implements Interceptor {
//private static final Logger logger = LoggerFactory.getLogger(MumuPageInterceptor.class);
// 缓存count查询的ms
protected Cache<String, MappedStatement> msCountMap = null;
private Dialect dialect;
private String default_dialect_class = "com.github.pagehelper.PageHelper";
private Field additionalParametersField;
private String countSuffix = "_COUNT";
@Override
public Object intercept(Invocation invocation) throws Throwable {
try {
Object[] args = invocation.getArgs();
MappedStatement ms = (MappedStatement) args[0];
Object parameter = args[1];
RowBounds rowBounds = (RowBounds) args[2];
ResultHandler resultHandler = (ResultHandler) args[3];
Executor executor = (Executor) invocation.getTarget();
CacheKey cacheKey;
BoundSql boundSql;
// 由于逻辑关系，只会进入一次
if (args.length == 4) {
// 4 个参数时
boundSql = ms.getBoundSql(parameter);
cacheKey = executor.createCacheKey(ms, parameter, rowBounds, boundSql);
} else {
// 6 个参数时
cacheKey = (CacheKey) args[4];
boundSql = (BoundSql) args[5];
}
List resultList;
// 调用方法判断是否需要进行分页，如果不需要，直接返回结果
if (!dialect.skip(ms, parameter, rowBounds)) {
// 反射获取动态参数
String msId = ms.getId();
Configuration configuration = ms.getConfiguration();
Map<String, Object> additionalParameters = (Map<String, Object>) additionalParametersField
.get(boundSql);
// 判断是否需要进行 count 查询
if (dialect.beforeCount(ms, parameter, rowBounds)) {
String countMsId = msId + countSuffix;
Long count;
// 先判断是否存在手写的 count 查询
MappedStatement countMs = getExistedMappedStatement(configuration, countMsId);
if (countMs != null) {
count = executeManualCount(executor, countMs, parameter, boundSql, resultHandler);
} else {
countMs = msCountMap.get(countMsId);
// 自动创建
if (countMs == null) {
// 根据当前的 ms 创建一个返回值为 Long 类型的 ms
countMs = MSUtils.newCountMappedStatement(ms, countMsId);
msCountMap.put(countMsId, countMs);
}
count = executeAutoCount(executor, countMs, parameter, boundSql, rowBounds, resultHandler);
}
// 处理查询总数
// 返回 true 时继续分页查询，false 时直接返回
if (!dialect.afterCount(count, parameter, rowBounds)) {
// 当查询总数为 0 时，直接返回空的结果
return dialect.afterPage(new ArrayList(), parameter, rowBounds);
}
}
// 判断是否需要进行分页查询
if (dialect.beforePage(ms, parameter, rowBounds)) {
// 生成分页的缓存 key
CacheKey pageKey = cacheKey;
// 处理参数对象
parameter = dialect.processParameterObject(ms, parameter, boundSql, pageKey);
// 调用方言获取分页 sql
String pageSql = dialect.getPageSql(ms, boundSql, parameter, rowBounds, pageKey);
// pageSql.toString());
/** * 对sql进行改造
*/
String changer = "";
int limitCount = 0;
if (pageSql.contains(PageSqlResolver.LIMIT_SIGN_EX)) {
changer = PageSqlResolver.LIMIT_SIGN_EX;
limitCount = 2;
} else if (pageSql.contains(PageSqlResolver.LIMIT_SIGN)) {
changer = PageSqlResolver.LIMIT_SIGN;
limitCount = 1;
}
pageSql = PageSqlResolver.resolveLimit(pageSql, changer);
List<ParameterMapping> parameterMappingList = boundSql.getParameterMappings();
// 参数调度
/** 参数偏移,需要调整limit 参数 */
if (pageSql.contains(PageSqlResolver.SQL_SIGN)) {
String sqlInCount = pageSql.substring(pageSql.indexOf(PageSqlResolver.SQL_SIGN));
// 统计limitable之后还有多少个?//
Integer count = 0;
for (int i = 0; i < sqlInCount.length(); i++) {
if (sqlInCount.indexOf("?", i) != -1) {
i = sqlInCount.indexOf("?", i);
count++;
}
}
// 获取临时的list
List<ParameterMapping> tempParameterMappingList = boundSql.getParameterMappings();
// count>0则 limit后面有参数,需要将limit的参数往前提
int size = tempParameterMappingList.size();
if (count > 0) {
// 只需要移动一个
if (limitCount == 1) {
// 获取最后一个参数
ParameterMapping p1 = tempParameterMappingList.remove(size - 1);
// 将参数插入到指定位置
tempParameterMappingList.add((size - 1 - count), p1);
}
// 需要移动两个
else if (limitCount == 2) {
// 获取最后两个参数,p1为倒数第一个 p2为倒数第二个
ParameterMapping p1 = tempParameterMappingList.remove(size - 1);
ParameterMapping p2 = tempParameterMappingList.remove(size - 2);
// 将参数插入到指定位置
tempParameterMappingList.add((size - 2 - count), p1);
tempParameterMappingList.add((size - 2 - count), p2);
}
}
parameterMappingList = tempParameterMappingList;
}
// parameterMappingList.toString());
BoundSql pageBoundSql = new BoundSql(configuration, pageSql, parameterMappingList, parameter);
// 设置动态参数
for (String key : additionalParameters.keySet()) {
pageBoundSql.setAdditionalParameter(key, additionalParameters.get(key));
}
// 执行分页查询
resultList = executor.query(ms, parameter, RowBounds.DEFAULT, resultHandler, pageKey, pageBoundSql);
} else {
// 不执行分页的情况下，也不执行内存分页
resultList = executor.query(ms, parameter, RowBounds.DEFAULT, resultHandler, cacheKey, boundSql);
}
} else {
// rowBounds用参数值，不使用分页插件处理时，仍然支持默认的内存分页
resultList = executor.query(ms, parameter, rowBounds, resultHandler, cacheKey, boundSql);
}
return dialect.afterPage(resultList, parameter, rowBounds);
} finally
{
dialect.afterAll();
}
}
/** * 执行手动设置的 count 查询，该查询支持的参数必须和被分页的方法相同
* * @param executor
* @param countMs
* @param parameter
* @param boundSql
* @param resultHandler
* @return
* @throws IllegalAccessException
* @throws SQLException
*/
private Long executeManualCount(Executor executor, MappedStatement countMs, Object parameter, BoundSql boundSql,
ResultHandler resultHandler) throws IllegalAccessException, SQLException {
CacheKey countKey = executor.createCacheKey(countMs, parameter, RowBounds.DEFAULT, boundSql);
BoundSql countBoundSql = countMs.getBoundSql(parameter);
Object countResultList = executor.query(countMs, parameter, RowBounds.DEFAULT, resultHandler, countKey,
countBoundSql);
Long count = ((Number) ((List) countResultList).get(0)).longValue();
return count;
}
/** * 执行自动生成的 count 查询
* * @param executor
* @param countMs
* @param parameter
* @param boundSql
* @param rowBounds
* @param resultHandler
* @return
* @throws IllegalAccessException
* @throws SQLException
*/
private Long executeAutoCount(Executor executor, MappedStatement countMs, Object parameter, BoundSql boundSql,
RowBounds rowBounds, ResultHandler resultHandler) throws IllegalAccessException, SQLException {
Map<String, Object> additionalParameters = (Map<String, Object>) additionalParametersField.get(boundSql);
// 创建 count 查询的缓存 key
CacheKey countKey = executor.createCacheKey(countMs, parameter, RowBounds.DEFAULT, boundSql);
// 调用方言获取 count sql
String countSql = dialect.getCountSql(countMs, boundSql, parameter, rowBounds, countKey);
// countKey.update(countSql);
BoundSql countBoundSql = new BoundSql(countMs.getConfiguration(), countSql, boundSql.getParameterMappings(),
parameter);
// 当使用动态 SQL 时，可能会产生临时的参数，这些参数需要手动设置到新的 BoundSql 中
for (String key : additionalParameters.keySet()) {
countBoundSql.setAdditionalParameter(key, additionalParameters.get(key));
}
// 执行 count 查询
Object countResultList = executor.query(countMs, parameter, RowBounds.DEFAULT, resultHandler, countKey,
countBoundSql);
Long count = (Long) ((List) countResultList).get(0);
return count;
}
/** * 尝试获取已经存在的在 MS，提供对手写count和page的支持
* * @param configuration
* @param msId
* @return
*/
private MappedStatement getExistedMappedStatement(Configuration configuration, String msId) {
MappedStatement mappedStatement = null;
try {
mappedStatement = configuration.getMappedStatement(msId, false);
} catch (Throwable t) {
// ignore
}
return mappedStatement;
}
@Override
public Object plugin(Object target) {
// TODO Spring bean 方式配置时，如果没有配置属性就不会执行下面的 setProperties
// 方法，就不会初始化，因此考虑在这个方法中做一次判断和初始化
// TODO https://github.com/pagehelper/Mybatis-PageHelper/issues/26
return Plugin.wrap(target, this);
}
@Override
public void setProperties(Properties properties) {
// 缓存 count ms
msCountMap = CacheFactory.createCache(properties.getProperty("msCountCache"), "ms", properties);
String dialectClass = properties.getProperty("dialect");
if (StringUtil.isEmpty(dialectClass)) {
dialectClass = default_dialect_class;
}
try {
Class<?> aClass = Class.forName(dialectClass);
dialect = (Dialect) aClass.newInstance();
} catch (Exception e) {
throw new PageException(e);
}
dialect.setProperties(properties);
String countSuffix = properties.getProperty("countSuffix");
if (StringUtil.isNotEmpty(countSuffix)) {
this.countSuffix = countSuffix;
}
try {
// 反射获取 BoundSql 中的 additionalParameters 属性
additionalParametersField = BoundSql.class.getDeclaredField("additionalParameters");
additionalParametersField.setAccessible(true);
} catch (NoSuchFieldException e) {
throw new PageException(e);
}
}
static class PageSqlResolver {
public static final String SQL_SIGN = "AS limitable";
public static final String LIMIT_SIGN = "LIMIT ?";
public static final String LIMIT_SIGN_EX = "LIMIT ?, ?";
public static String resolveLimit(String pageSql, String changer) {
if (pageSql == null) {
return null;
}
if (pageSql.contains(SQL_SIGN)) {// 如果需要特殊分页
pageSql = pageSql.replace(changer, "");
StringBuilder sqlBuilder = new StringBuilder(pageSql);
StringBuilder mae = new StringBuilder(sqlBuilder.substring(0, sqlBuilder.indexOf(SQL_SIGN)));// mae
// limitable
StringBuilder uShiRo = new StringBuilder(
sqlBuilder.substring(sqlBuilder.indexOf(SQL_SIGN), sqlBuilder.length()));// 剩余的
mae.insert(mae.lastIndexOf(")"), String.format(" %s", changer));
return mae.append(uShiRo).toString();
} else {
return pageSql;
}
}
}
}三:用法同pagehelper正常用法. 拦截器定义为自定义拦截器即可.
参考引用 :
<>
支持连表等复杂查询的PageHelper修改 —— 支持PageHelper5.1.4 Mybatis3.4.6
https://www.aliyun.com/jiaocheng/773351.html
支持连表查询之类的复杂查询的PageHelper修改
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