1.1创建ThreadLocal工具类（作为业务逻辑结果存放类）
package org.springblade.sample.utils;
public class QueryContext {
private static final ThreadLocal<Long> totalInThreadLocal = new ThreadLocal<>();
public static void setTotalIn(long totalIn) {
totalInThreadLocal.set(totalIn);
}
public static long getTotalIn() {
return totalInThreadLocal.get() != null ? totalInThreadLocal.get() : 0;
}
public static void clear() {
totalInThreadLocal.remove();
}
}
2.1重构Mybatis-plus分页查询total总数逻辑（通过实现InnerInterceptor接口进行重构,代码如下，根据注释进行对应业务调整即可）
package org.springblade.sample.config;
import com.baomidou.mybatisplus.annotation.DbType;
import com.baomidou.mybatisplus.core.metadata.IPage;
import com.baomidou.mybatisplus.core.metadata.OrderItem;
import com.baomidou.mybatisplus.core.toolkit.*;
import com.baomidou.mybatisplus.extension.parser.JsqlParserGlobal;
import com.baomidou.mybatisplus.extension.plugins.inner.InnerInterceptor;
import com.baomidou.mybatisplus.extension.plugins.pagination.DialectFactory;
import com.baomidou.mybatisplus.extension.plugins.pagination.DialectModel;
import com.baomidou.mybatisplus.extension.plugins.pagination.dialects.IDialect;
import com.baomidou.mybatisplus.extension.toolkit.JdbcUtils;
import com.baomidou.mybatisplus.extension.toolkit.PropertyMapper;
import com.baomidou.mybatisplus.extension.toolkit.SqlParserUtils;
import groovy.util.logging.Slf4j;
import lombok.Data;
import lombok.NoArgsConstructor;
import net.sf.jsqlparser.JSQLParserException;
import net.sf.jsqlparser.expression.Alias;
import net.sf.jsqlparser.expression.Expression;
import net.sf.jsqlparser.schema.Column;
import net.sf.jsqlparser.schema.Table;
import net.sf.jsqlparser.statement.select.*;
import org.apache.ibatis.cache.CacheKey;
import org.apache.ibatis.executor.Executor;
import org.apache.ibatis.logging.Log;
import org.apache.ibatis.logging.LogFactory;
import org.apache.ibatis.mapping.BoundSql;
import org.apache.ibatis.mapping.MappedStatement;
import org.apache.ibatis.mapping.ParameterMapping;
import org.apache.ibatis.mapping.ResultMap;
import org.apache.ibatis.session.Configuration;
import org.apache.ibatis.session.ResultHandler;
import org.apache.ibatis.session.RowBounds;
import org.springblade.core.tool.utils.StringUtil;
import org.springblade.sample.utils.QueryContext;
import java.sql.SQLException;
import java.util.*;
import java.util.concurrent.ConcurrentHashMap;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import java.util.stream.Collectors;
/**
* 分页拦截器
* <p>
* 默认对 left join 进行优化,虽然能优化count,但是加上分页的话如果1对多本身结果条数就是不正确的
*
* @author hubin
* @since 3.4.0
*/
@lombok.extern.slf4j.Slf4j
@Data
@NoArgsConstructor
@org.springframework.context.annotation.Configuration
@Slf4j
public class PaginationInnerInterceptor implements InnerInterceptor {
/**
* 获取jsqlparser中count的SelectItem
*/
protected static final List<SelectItem> COUNT_SELECT_ITEM = Collections.singletonList(new SelectExpressionItem(new Column().withColumnName("COUNT(*)")).withAlias(new Alias("total")));
protected static final Map<String, MappedStatement> countMsCache = new ConcurrentHashMap<>();
protected final Log logger = LogFactory.getLog(this.getClass());
/**
* 表名
*/
private final String V_SAMPLE_COVID19 = "v_sample_covid19";
private final String T_SAMPLE_COVID19 = "t_sample_covid19";
private final String T_SAMPLE_FLU = "t_sample_flu";
private final String T_SAMPLE_HADV = "t_sample_hadv";
private final String T_SAMPLE_HMPV = "t_sample_hmpv";
private final String T_SAMPLE_HPIV = "t_sample_hpiv";
private final String T_SAMPLE_METAV = "t_sample_metav";
private final String T_SAMPLE_RSV = "t_sample_rsv";
/**
* 溢出总页数后是否进行处理
*/
protected boolean overflow;
/**
* 单页分页条数限制
*/
protected Long maxLimit;
/**
* 数据库类型
* <p>
* 查看 {@link #findIDialect(Executor)} 逻辑
*/
private DbType dbType;
/**
* 方言实现类
* <p>
* 查看 {@link #findIDialect(Executor)} 逻辑
*/
private IDialect dialect;
/**
* 生成 countSql 优化掉 join
* 现在只支持 left join
*
* @since 3.4.2
*/
protected boolean optimizeJoin = true;
public PaginationInnerInterceptor(DbType dbType) {
this.dbType = dbType;
}
public PaginationInnerInterceptor(IDialect dialect) {
this.dialect = dialect;
}
/***
* 重构willDoQuery获取序列未上传数量（根据检索结果进行实时更新）
* @param executor Executor(可能是代理对象)
* @param ms MappedStatement
* @param parameter parameter
* @param rowBounds rowBounds
* @param resultHandler resultHandler
* @param boundSql boundSql
*/
public boolean willDoQuery(Executor executor, MappedStatement ms, Object parameter, RowBounds rowBounds, ResultHandler resultHandler, BoundSql boundSql) throws SQLException {
IPage<?> page = ParameterUtils.findPage(parameter).orElse(null);
if (page == null || page.getSize() < 0 || !page.searchCount() || resultHandler != Executor.NO_RESULT_HANDLER) {
return true;
}
BoundSql countSql;
BoundSql countSqlIn;
MappedStatement countMs = buildCountMappedStatement(ms, page.countId());
if (countMs != null) {
countSql = countMs.getBoundSql(parameter);
countSqlIn = countMs.getBoundSql(parameter);
} else {
countMs = buildAutoCountMappedStatement(ms);
String countSqlStr = autoCountSql(page, boundSql.getSql());
PluginUtils.MPBoundSql mpBoundSql = PluginUtils.mpBoundSql(boundSql);
countSql = new BoundSql(countMs.getConfiguration(), countSqlStr, mpBoundSql.parameterMappings(), parameter);
countSqlIn = new BoundSql(countMs.getConfiguration(), countSqlStr + " and seq_num = '0'", mpBoundSql.parameterMappings(), parameter);
PluginUtils.setAdditionalParameter(countSql, mpBoundSql.additionalParameters());
PluginUtils.setAdditionalParameter(countSqlIn, mpBoundSql.additionalParameters());
}
// 执行第一个查询 (result)
CacheKey cacheKey = executor.createCacheKey(countMs, parameter, rowBounds, countSql);
List<Object> result = executor.query(countMs, parameter, rowBounds, resultHandler, cacheKey, countSql);
long total = 0;
if (CollectionUtils.isNotEmpty(result)) {
// 个别数据库 count 没数据不会返回 0
Object o = result.get(0);
if (o != null) {
total = Long.parseLong(o.toString());
}
}
page.setTotal(total);
long totalIn = 0;
//获取表名
String tableName = getTableFromSql(boundSql.getSql());
// 执行第二个查询 (resultIn)
if (StringUtil.isNotBlank(tableName)) {
//根据表名判断是否进行查询
if (this.suitTableName(tableName)) {
CacheKey cacheKeyIn = executor.createCacheKey(countMs, parameter, rowBounds, countSqlIn);
List<Object> resultIn = executor.query(countMs, parameter, rowBounds, resultHandler, cacheKeyIn, countSqlIn);
log.info("未上传序列数：{}", Long.parseLong(resultIn.get(0).toString()));
if (CollectionUtils.isNotEmpty(resultIn)) {
// 个别数据库 count 没数据不会返回 0
Object o = resultIn.get(0);
if (o != null) {
totalIn = Long.parseLong(o.toString());
}
}
}
}
// 将 totalIn 设置到 ThreadLocal 中
QueryContext.setTotalIn(totalIn);
return continuePage(page);
}
@Override
public void beforeQuery(Executor executor, MappedStatement ms, Object parameter, RowBounds rowBounds, ResultHandler resultHandler, BoundSql boundSql) {
IPage<?> page = ParameterUtils.findPage(parameter).orElse(null);
if (null == page) {
return;
}
// 处理 orderBy 拼接
boolean addOrdered = false;
String buildSql = boundSql.getSql();
List<OrderItem> orders = page.orders();
if (CollectionUtils.isNotEmpty(orders)) {
addOrdered = true;
buildSql = this.concatOrderBy(buildSql, orders);
}
// size 小于 0 且不限制返回值则不构造分页sql
Long _limit = page.maxLimit() != null ? page.maxLimit() : maxLimit;
if (page.getSize() < 0 && null == _limit) {
if (addOrdered) {
PluginUtils.mpBoundSql(boundSql).sql(buildSql);
}
return;
}
handlerLimit(page, _limit);
IDialect dialect = findIDialect(executor);
final Configuration configuration = ms.getConfiguration();
DialectModel model = dialect.buildPaginationSql(buildSql, page.offset(), page.getSize());
PluginUtils.MPBoundSql mpBoundSql = PluginUtils.mpBoundSql(boundSql);
List<ParameterMapping> mappings = mpBoundSql.parameterMappings();
Map<String, Object> additionalParameter = mpBoundSql.additionalParameters();
model.consumers(mappings, configuration, additionalParameter);
mpBoundSql.sql(model.getDialectSql());
mpBoundSql.parameterMappings(mappings);
}
/**
* 获取分页方言类的逻辑
*
* @param executor Executor
* @return 分页方言类
*/
protected IDialect findIDialect(Executor executor) {
if (dialect != null) {
return dialect;
}
if (dbType != null) {
dialect = DialectFactory.getDialect(dbType);
return dialect;
}
return DialectFactory.getDialect(JdbcUtils.getDbType(executor));
}
/**
* 获取指定的 id 的 MappedStatement
*
* @param ms MappedStatement
* @param countId id
* @return MappedStatement
*/
protected MappedStatement buildCountMappedStatement(MappedStatement ms, String countId) {
if (StringUtils.isNotBlank(countId)) {
final String id = ms.getId();
if (!countId.contains(StringPool.DOT)) {
countId = id.substring(0, id.lastIndexOf(StringPool.DOT) + 1) + countId;
}
final Configuration configuration = ms.getConfiguration();
try {
return CollectionUtils.computeIfAbsent(countMsCache, countId, key -> configuration.getMappedStatement(key, false));
} catch (Exception e) {
logger.warn(String.format("can not find this countId: [\"%s\"]", countId));
}
}
return null;
}
/**
* 构建 mp 自用自动的 MappedStatement
*
* @param ms MappedStatement
* @return MappedStatement
*/
protected MappedStatement buildAutoCountMappedStatement(MappedStatement ms) {
final String countId = ms.getId() + "_mpCount";
final Configuration configuration = ms.getConfiguration();
return CollectionUtils.computeIfAbsent(countMsCache, countId, key -> {
MappedStatement.Builder builder = new MappedStatement.Builder(configuration, key, ms.getSqlSource(), ms.getSqlCommandType());
builder.resource(ms.getResource());
builder.fetchSize(ms.getFetchSize());
builder.statementType(ms.getStatementType());
builder.timeout(ms.getTimeout());
builder.parameterMap(ms.getParameterMap());
builder.resultMaps(Collections.singletonList(new ResultMap.Builder(configuration, Constants.MYBATIS_PLUS, Long.class, Collections.emptyList()).build()));
builder.resultSetType(ms.getResultSetType());
builder.cache(ms.getCache());
builder.flushCacheRequired(ms.isFlushCacheRequired());
builder.useCache(ms.isUseCache());
return builder.build();
});
}
/**
* 获取自动优化的 countSql
*
* @param page 参数
* @param sql sql
* @return countSql
*/
protected String autoCountSql(IPage<?> page, String sql) {
if (!page.optimizeCountSql()) {
return lowLevelCountSql(sql);
}
try {
Select select = (Select) JsqlParserGlobal.parse(sql);
SelectBody selectBody = select.getSelectBody();
// https://github.com/baomidou/mybatis-plus/issues/3920 分页增加union语法支持
if (selectBody instanceof SetOperationList) {
return lowLevelCountSql(sql);
}
PlainSelect plainSelect = (PlainSelect) select.getSelectBody();
Distinct distinct = plainSelect.getDistinct();
GroupByElement groupBy = plainSelect.getGroupBy();
// 包含 distinct、groupBy 不优化
if (null != distinct || null != groupBy) {
return lowLevelCountSql(select.toString());
}
// 优化 order by 在非分组情况下
List<OrderByElement> orderBy = plainSelect.getOrderByElements();
if (CollectionUtils.isNotEmpty(orderBy)) {
boolean canClean = true;
for (OrderByElement order : orderBy) {
// order by 里带参数,不去除order by
Expression expression = order.getExpression();
if (!(expression instanceof Column) && expression.toString().contains(StringPool.QUESTION_MARK)) {
canClean = false;
break;
}
}
if (canClean) {
plainSelect.setOrderByElements(null);
}
}
for (SelectItem item : plainSelect.getSelectItems()) {
if (item.toString().contains(StringPool.QUESTION_MARK)) {
return lowLevelCountSql(select.toString());
}
}
// 包含 join 连表,进行判断是否移除 join 连表
if (optimizeJoin && page.optimizeJoinOfCountSql()) {
List<Join> joins = plainSelect.getJoins();
if (CollectionUtils.isNotEmpty(joins)) {
boolean canRemoveJoin = true;
String whereS = Optional.ofNullable(plainSelect.getWhere()).map(Expression::toString).orElse(StringPool.EMPTY);
// 不区分大小写
whereS = whereS.toLowerCase();
for (Join join : joins) {
if (!join.isLeft()) {
canRemoveJoin = false;
break;
}
FromItem rightItem = join.getRightItem();
String str = "";
if (rightItem instanceof Table) {
Table table = (Table) rightItem;
str = Optional.ofNullable(table.getAlias()).map(Alias::getName).orElse(table.getName()) + StringPool.DOT;
} else if (rightItem instanceof SubSelect) {
SubSelect subSelect = (SubSelect) rightItem;
/* 如果 left join 是子查询，并且子查询里包含 ?(代表有入参) 或者 where 条件里包含使用 join 的表的字段作条件,就不移除 join */
if (subSelect.toString().contains(StringPool.QUESTION_MARK)) {
canRemoveJoin = false;
break;
}
str = subSelect.getAlias().getName() + StringPool.DOT;
}
// 不区分大小写
str = str.toLowerCase();
if (whereS.contains(str)) {
/* 如果 where 条件里包含使用 join 的表的字段作条件,就不移除 join */
canRemoveJoin = false;
break;
}
for (Expression expression : join.getOnExpressions()) {
if (expression.toString().contains(StringPool.QUESTION_MARK)) {
/* 如果 join 里包含 ?(代表有入参) 就不移除 join */
canRemoveJoin = false;
break;
}
}
}
if (canRemoveJoin) {
plainSelect.setJoins(null);
}
}
}
// 优化 SQL
plainSelect.setSelectItems(COUNT_SELECT_ITEM);
return select.toString();
} catch (JSQLParserException e) {
// 无法优化使用原 SQL
logger.warn("optimize this sql to a count sql has exception, sql:\"" + sql + "\", exception:\n" + e.getCause());
} catch (Exception e) {
logger.warn("optimize this sql to a count sql has error, sql:\"" + sql + "\", exception:\n" + e);
}
return lowLevelCountSql(sql);
}
/**
* 无法进行count优化时,降级使用此方法
*
* @param originalSql 原始sql
* @return countSql
*/
protected String lowLevelCountSql(String originalSql) {
return SqlParserUtils.getOriginalCountSql(originalSql);
}
/**
* 查询SQL拼接Order By
*
* @param originalSql 需要拼接的SQL
* @return ignore
*/
public String concatOrderBy(String originalSql, List<OrderItem> orderList) {
try {
Select select = (Select) JsqlParserGlobal.parse(originalSql);
SelectBody selectBody = select.getSelectBody();
if (selectBody instanceof PlainSelect) {
PlainSelect plainSelect = (PlainSelect) selectBody;
List<OrderByElement> orderByElements = plainSelect.getOrderByElements();
List<OrderByElement> orderByElementsReturn = addOrderByElements(orderList, orderByElements);
plainSelect.setOrderByElements(orderByElementsReturn);
return select.toString();
} else if (selectBody instanceof SetOperationList) {
SetOperationList setOperationList = (SetOperationList) selectBody;
List<OrderByElement> orderByElements = setOperationList.getOrderByElements();
List<OrderByElement> orderByElementsReturn = addOrderByElements(orderList, orderByElements);
setOperationList.setOrderByElements(orderByElementsReturn);
return select.toString();
} else if (selectBody instanceof WithItem) {
// todo: don't known how to resole
return originalSql;
} else {
return originalSql;
}
} catch (JSQLParserException e) {
logger.warn("failed to concat orderBy from IPage, exception:\n" + e.getCause());
} catch (Exception e) {
logger.warn("failed to concat orderBy from IPage, exception:\n" + e);
}
return originalSql;
}
protected List<OrderByElement> addOrderByElements(List<OrderItem> orderList, List<OrderByElement> orderByElements) {
List<OrderByElement> additionalOrderBy = orderList.stream().filter(item -> StringUtils.isNotBlank(item.getColumn())).map(item -> {
OrderByElement element = new OrderByElement();
element.setExpression(new Column(item.getColumn()));
element.setAsc(item.isAsc());
element.setAscDescPresent(true);
return element;
}).collect(Collectors.toList());
if (CollectionUtils.isEmpty(orderByElements)) {
return additionalOrderBy;
}
// github pull/3550 优化排序，比如：默认 order by id 前端传了name排序，设置为 order by name,id
additionalOrderBy.addAll(orderByElements);
return additionalOrderBy;
}
/**
* count 查询之后,是否继续执行分页
*
* @param page 分页对象
* @return 是否
*/
protected boolean continuePage(IPage<?> page) {
if (page.getTotal() <= 0) {
return false;
}
if (page.getCurrent() > page.getPages()) {
if (overflow) {
//溢出总页数处理
handlerOverflow(page);
} else {
// 超过最大范围，未设置溢出逻辑中断 list 执行
return false;
}
}
return true;
}
/**
* 处理超出分页条数限制,默认归为限制数
*
* @param page IPage
*/
protected void handlerLimit(IPage<?> page, Long limit) {
final long size = page.getSize();
if (limit != null && limit > 0 && (size > limit || size < 0)) {
page.setSize(limit);
}
}
/**
* 处理页数溢出,默认设置为第一页
*
* @param page IPage
*/
protected void handlerOverflow(IPage<?> page) {
page.setCurrent(1);
}
@Override
public void setProperties(Properties properties) {
PropertyMapper.newInstance(properties).whenNotBlank("overflow", Boolean::parseBoolean, this::setOverflow).whenNotBlank("dbType", DbType::getDbType, this::setDbType).whenNotBlank("dialect", ClassUtils::newInstance, this::setDialect).whenNotBlank("maxLimit", Long::parseLong, this::setMaxLimit).whenNotBlank("optimizeJoin", Boolean::parseBoolean, this::setOptimizeJoin);
}
protected String getTableFromSql(String sql) {
String regex = "(?i)from\\s+([a-zA-Z0-9_]+)";
Pattern pattern = Pattern.compile(regex);
Matcher matcher = pattern.matcher(sql);
if (matcher.find()) {
return matcher.group(1);
}
return null;
}
/**
* 判断是否进行未上传序列数计算
* @param tableName 表名
*/
private boolean suitTableName(String tableName) {
switch (tableName) {
case V_SAMPLE_COVID19:
case T_SAMPLE_RSV:
case T_SAMPLE_COVID19:
case T_SAMPLE_FLU:
case T_SAMPLE_HADV:
case T_SAMPLE_HMPV:
case T_SAMPLE_HPIV:
case T_SAMPLE_METAV:
return true;
default:
return false;
}
}
}
