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refactor: 分页查询逻辑优化。

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This commit is contained in:
Suomm 2023-06-09 21:01:13 +08:00
parent d20d4cc2d3
commit a69e1e85f0
3 changed files with 44 additions and 132 deletions
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53
mybatis-flex-core/src/main/java/com/mybatisflex/core/BaseMapper.java
View File

@ -652,75 +652,26 @@ public interface BaseMapper<T> {
default <R> Page<R> paginateAs(Page<R> page, QueryWrapper queryWrapper, Class<R> asType, Consumer<FieldQueryBuilder<R>>... consumers) {
List<QueryColumn> selectColumns = CPI.getSelectColumns(queryWrapper);
List<QueryOrderBy> orderBys = CPI.getOrderBys(queryWrapper);
List<Join> joins = CPI.getJoins(queryWrapper);
boolean removedJoins = true;
// 只有 totalRow 小于 0 的时候才会去查询总量
// 这样方便用户做总数缓存，而非每次都要去查询总量
// 一般的分页场景中，只有第一页的时候有必要去查询总量，第二页以后是不需要的
if (page.getTotalRow() < 0) {
//移除 select
CPI.setSelectColumns(queryWrapper, Collections.singletonList(count().as("total")));
//移除 OrderBy
if (CollectionUtil.isNotEmpty(orderBys)) {
CPI.setOrderBys(queryWrapper, null);
}
//移除 left join
if (joins != null && !joins.isEmpty()) {
for (Join join : joins) {
if (!Join.TYPE_LEFT.equals(CPI.getJoinType(join))) {
removedJoins = false;
break;
}
}
} else {
removedJoins = false;
}
if (removedJoins) {
List<String> joinTables = new ArrayList<>();
joins.forEach(join -> {
QueryTable joinQueryTable = CPI.getJoinQueryTable(join);
if (joinQueryTable != null && StringUtil.isNotBlank(joinQueryTable.getName())) {
joinTables.add(joinQueryTable.getName());
}
});
QueryCondition where = CPI.getWhereQueryCondition(queryWrapper);
if (CPI.containsTable(where, CollectionUtil.toArrayString(joinTables))) {
removedJoins = false;
}
}
if (removedJoins) {
CPI.setJoins(queryWrapper, null);
}
queryWrapper = MapperUtil.optimizeCountQueryWrapper(queryWrapper);
long count = selectCountByQuery(queryWrapper);
page.setTotalRow(count);
}
if (page.getTotalRow() == 0 || page.getPageNumber() > page.getTotalPage()) {
if (page.isEmpty()) {
return page;
}
//重置 selectColumns
CPI.setSelectColumns(queryWrapper, selectColumns);
//重置 orderBys
if (CollectionUtil.isNotEmpty(orderBys)) {
CPI.setOrderBys(queryWrapper, orderBys);
}
//重置 join
if (removedJoins) {
CPI.setJoins(queryWrapper, joins);
}
int offset = page.getPageSize() * (page.getPageNumber() - 1);
queryWrapper.limit(offset, page.getPageSize());

6
mybatis-flex-core/src/main/java/com/mybatisflex/core/paginate/Page.java
View File

@ -1,4 +1,4 @@
/**
/*
* Copyright (c) 2022-2023, Mybatis-Flex (fuhai999@gmail.com).
* <p>
* Licensed under the Apache License, Version 2.0 (the "License");
@ -128,6 +128,10 @@ public class Page<T> implements Serializable {
}
}
public boolean isEmpty() {
return getTotalRow() == 0 || getPageNumber() > getTotalPage();
}
public <R> Page<R> map(Function<? super T, ? extends R> mapper) {
Page<R> newPage = new Page<>();

57
mybatis-flex-core/src/main/java/com/mybatisflex/core/row/RowMapper.java
View File

@ -1,4 +1,4 @@
/**
/*
* Copyright (c) 2022-2023, Mybatis-Flex (fuhai999@gmail.com).
* <p>
* Licensed under the Apache License, Version 2.0 (the "License");
@ -21,11 +21,14 @@ import com.mybatisflex.core.paginate.Page;
import com.mybatisflex.core.provider.RowSqlProvider;
import com.mybatisflex.core.query.*;
import com.mybatisflex.core.util.CollectionUtil;
import com.mybatisflex.core.util.MapperUtil;
import com.mybatisflex.core.util.StringUtil;
import org.apache.ibatis.annotations.*;
import org.apache.ibatis.exceptions.TooManyResultsException;
import java.util.*;
import java.util.Collection;
import java.util.List;
import java.util.Map;
import static com.mybatisflex.core.query.QueryMethods.count;
@ -435,72 +438,26 @@ public interface RowMapper {
List<QueryOrderBy> orderBys = CPI.getOrderBys(queryWrapper);
List<Join> joins = CPI.getJoins(queryWrapper);
boolean removedJoins = true;
// 只有 totalRow 小于 0 的时候才会去查询总量
// 这样方便用户做总数缓存，而非每次都要去查询总量
// 一般的分页场景中，只有第一页的时候有必要去查询总量，第二页以后是不需要的
if (page.getTotalRow() < 0) {
//移除 seelct
CPI.setSelectColumns(queryWrapper, Collections.singletonList(count().as("total")));
//移除 OrderBy
if (CollectionUtil.isNotEmpty(orderBys)) {
CPI.setOrderBys(queryWrapper, null);
}
//移除 left join
if (joins != null && !joins.isEmpty()) {
for (Join join : joins) {
if (!Join.TYPE_LEFT.equals(CPI.getJoinType(join))) {
removedJoins = false;
break;
}
}
} else {
removedJoins = false;
}
if (removedJoins) {
List<String> joinTables = new ArrayList<>();
joins.forEach(join -> {
QueryTable joinQueryTable = CPI.getJoinQueryTable(join);
if (joinQueryTable != null && StringUtil.isNotBlank(joinQueryTable.getName())) {
joinTables.add(joinQueryTable.getName());
}
});
QueryCondition where = CPI.getWhereQueryCondition(queryWrapper);
if (CPI.containsTable(where, CollectionUtil.toArrayString(joinTables))) {
removedJoins = false;
}
}
if (removedJoins) {
CPI.setJoins(queryWrapper, null);
}
queryWrapper = MapperUtil.optimizeCountQueryWrapper(queryWrapper);
long count = selectCountByQuery(schema,tableName, queryWrapper);
page.setTotalRow(count);
}
if (page.getTotalRow() == 0 || page.getPageNumber() > page.getTotalPage()) {
if (page.isEmpty()) {
return page;
}
//重置 selectColumns
CPI.setSelectColumns(queryWrapper, selectColumns);
//重置 orderBys
if (CollectionUtil.isNotEmpty(orderBys)) {
CPI.setOrderBys(queryWrapper, orderBys);
}
//重置 join
if (removedJoins) {
CPI.setJoins(queryWrapper, joins);
}
int offset = page.getPageSize() * (page.getPageNumber() - 1);
queryWrapper.limit(offset, page.getPageSize());