com.baomidou.mybatisplus.extension.plugins.PaginationInterceptor Maven / Gradle / Ivy
Show all versions of mybatis-plus-extension Show documentation
/*
* Copyright (c) 2011-2020, hubin ([email protected]).
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not
* use this file except in compliance with the License. You may obtain a copy of
* the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations under
* the License.
*/
package com.baomidou.mybatisplus.extension.plugins;
import static java.util.stream.Collectors.joining;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.Arrays;
import java.util.Map;
import java.util.Properties;
import org.apache.ibatis.executor.statement.StatementHandler;
import org.apache.ibatis.mapping.BoundSql;
import org.apache.ibatis.mapping.MappedStatement;
import org.apache.ibatis.mapping.SqlCommandType;
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.reflection.MetaObject;
import org.apache.ibatis.reflection.SystemMetaObject;
import org.apache.ibatis.scripting.defaults.DefaultParameterHandler;
import org.apache.ibatis.session.RowBounds;
import com.baomidou.mybatisplus.annotation.DbType;
import com.baomidou.mybatisplus.core.MybatisDefaultParameterHandler;
import com.baomidou.mybatisplus.core.metadata.IPage;
import com.baomidou.mybatisplus.core.parser.ISqlParser;
import com.baomidou.mybatisplus.core.parser.SqlInfo;
import com.baomidou.mybatisplus.core.toolkit.ArrayUtils;
import com.baomidou.mybatisplus.core.toolkit.ExceptionUtils;
import com.baomidou.mybatisplus.core.toolkit.PluginUtils;
import com.baomidou.mybatisplus.core.toolkit.StringPool;
import com.baomidou.mybatisplus.core.toolkit.StringUtils;
import com.baomidou.mybatisplus.extension.handlers.AbstractSqlParserHandler;
import com.baomidou.mybatisplus.extension.plugins.pagination.DialectFactory;
import com.baomidou.mybatisplus.extension.toolkit.JdbcUtils;
import com.baomidou.mybatisplus.extension.toolkit.SqlParserUtils;
import lombok.Setter;
import lombok.experimental.Accessors;
/**
*
* 分页拦截器
*
*
* @author hubin
* @since 2016-01-23
*/
@Setter
@Accessors(chain = true)
@Intercepts({@Signature(type = StatementHandler.class, method = "prepare", args = {Connection.class, Integer.class})})
public class PaginationInterceptor extends AbstractSqlParserHandler implements Interceptor {
/**
* COUNT SQL 解析
*/
private ISqlParser sqlParser;
/**
* 溢出总页数，设置第一页
*/
private boolean overflow = false;
/**
* 方言类型
*/
private String dialectType;
/**
* 方言实现类
*/
private String dialectClazz;
/**
* 查询SQL拼接Order By
*
* @param originalSql 需要拼接的SQL
* @param page page对象
* @param orderBy 是否需要拼接Order By
* @return
*/
public static String concatOrderBy(String originalSql, IPage page, boolean orderBy) {
if (orderBy && (ArrayUtils.isNotEmpty(page.ascs())
|| ArrayUtils.isNotEmpty(page.descs()))) {
StringBuilder buildSql = new StringBuilder(originalSql);
String ascStr = concatOrderBuilder(page.ascs(), " ASC");
String descStr = concatOrderBuilder(page.descs(), " DESC");
if (StringUtils.isNotEmpty(ascStr) && StringUtils.isNotEmpty(descStr)) {
ascStr += ", ";
}
if (StringUtils.isNotEmpty(ascStr) || StringUtils.isNotEmpty(descStr)) {
buildSql.append(" ORDER BY ").append(ascStr).append(descStr);
}
return buildSql.toString();
}
return originalSql;
}
/**
* 拼接多个排序方法
*
* @param columns
* @param orderWord
*/
private static String concatOrderBuilder(String[] columns, String orderWord) {
if (ArrayUtils.isNotEmpty(columns)) {
return Arrays.stream(columns).filter(StringUtils::isNotEmpty)
.collect(joining(StringPool.COMMA, StringPool.EMPTY, orderWord));
}
return StringUtils.EMPTY;
}
/**
* Physical Page Interceptor for all the queries with parameter {@link RowBounds}
*/
@Override
public Object intercept(Invocation invocation) throws Throwable {
StatementHandler statementHandler = (StatementHandler) PluginUtils.realTarget(invocation.getTarget());
MetaObject metaObject = SystemMetaObject.forObject(statementHandler);
// SQL 解析
this.sqlParser(metaObject);
// 先判断是不是SELECT操作
MappedStatement mappedStatement = (MappedStatement) metaObject.getValue("delegate.mappedStatement");
if (!SqlCommandType.SELECT.equals(mappedStatement.getSqlCommandType())) {
return invocation.proceed();
}
// 针对定义了rowBounds，做为mapper接口方法的参数
BoundSql boundSql = (BoundSql) metaObject.getValue("delegate.boundSql");
Object paramObj = boundSql.getParameterObject();
// 判断参数里是否有page对象
IPage page = null;
if (paramObj instanceof IPage) {
page = (IPage) paramObj;
} else if (paramObj instanceof Map) {
for (Object arg : ((Map) paramObj).values()) {
if (arg instanceof IPage) {
page = (IPage) arg;
break;
}
}
}
/**
* 不需要分页的场合，如果 size 小于 0 返回结果集
*/
if (null == page || page.getSize() < 0) {
return invocation.proceed();
}
String originalSql = boundSql.getSql();
Connection connection = (Connection) invocation.getArgs()[0];
DbType dbType = StringUtils.isNotEmpty(dialectType) ? DbType.getDbType(dialectType)
: JdbcUtils.getDbType(connection.getMetaData().getURL());
boolean orderBy = true;
if (page.getTotal() == 0) {
SqlInfo sqlInfo = SqlParserUtils.getOptimizeCountSql(page.optimizeCountSql(), sqlParser, originalSql);
orderBy = sqlInfo.isOrderBy();
this.queryTotal(overflow, sqlInfo.getSql(), mappedStatement, boundSql, page, connection);
if (page.getTotal() <= 0) {
return invocation.proceed();
}
}
String buildSql = concatOrderBy(originalSql, page, orderBy);
originalSql = DialectFactory.buildPaginationSql(page, buildSql, dbType, dialectClazz);
/*
* 禁用内存分页
* 内存分页会查询所有结果出来处理（这个很吓人的），如果结果变化频繁这个数据还会不准。
*/
metaObject.setValue("delegate.boundSql.sql", originalSql);
metaObject.setValue("delegate.rowBounds.offset", RowBounds.NO_ROW_OFFSET);
metaObject.setValue("delegate.rowBounds.limit", RowBounds.NO_ROW_LIMIT);
return invocation.proceed();
}
/**
* 查询总记录条数
*
* @param sql
* @param mappedStatement
* @param boundSql
* @param page
*/
protected void queryTotal(boolean overflowCurrent, String sql, MappedStatement mappedStatement, BoundSql boundSql, IPage page, Connection connection) {
try (PreparedStatement statement = connection.prepareStatement(sql)) {
DefaultParameterHandler parameterHandler = new MybatisDefaultParameterHandler(mappedStatement, boundSql.getParameterObject(), boundSql);
parameterHandler.setParameters(statement);
long total = 0;
try (ResultSet resultSet = statement.executeQuery()) {
if (resultSet.next()) {
total = resultSet.getLong(1);
}
}
page.setTotal(total);
/*
* 溢出总页数，设置第一页
*/
long pages = page.getPages();
if (overflowCurrent && page.getCurrent() > pages) {
// 设置为第一条
page.setCurrent(1);
}
} catch (Exception e) {
throw ExceptionUtils.mpe("Error: Method queryTotal execution error.", e);
}
}
@Override
public Object plugin(Object target) {
if (target instanceof StatementHandler) {
return Plugin.wrap(target, this);
}
return target;
}
@Override
public void setProperties(Properties prop) {
String dialectType = prop.getProperty("dialectType");
String dialectClazz = prop.getProperty("dialectClazz");
if (StringUtils.isNotEmpty(dialectType)) {
this.dialectType = dialectType;
}
if (StringUtils.isNotEmpty(dialectClazz)) {
this.dialectClazz = dialectClazz;
}
}
}