/**
* Copyright (c) 2011-2020, hubin (jobob@qq.com).
* <p>
* 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
* <p>
* http://www.apache.org/licenses/LICENSE-2.0
* <p>
* 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.plugins;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.Properties;
import org.apache.ibatis.executor.statement.StatementHandler;
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.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.MybatisDefaultParameterHandler;
import com.baomidou.mybatisplus.entity.CountOptimize;
import com.baomidou.mybatisplus.plugins.pagination.DialectFactory;
import com.baomidou.mybatisplus.plugins.pagination.Pagination;
import com.baomidou.mybatisplus.toolkit.JdbcUtils;
import com.baomidou.mybatisplus.toolkit.PluginUtils;
import com.baomidou.mybatisplus.toolkit.SqlUtils;
import com.baomidou.mybatisplus.toolkit.StringUtils;
/**
* <p>
* 分页拦截器
* </p>
*
* @author hubin
* @Date 2016-01-23
*/
@Intercepts({@Signature(type = StatementHandler.class, method = "prepare", args = {Connection.class, Integer.class})})
public class PaginationInterceptor implements Interceptor {
private static final Log logger = LogFactory.getLog(PaginationInterceptor.class);
/* 溢出总页数,设置第一页 */
private boolean overflowCurrent = false;
/* 是否设置动态数据源 设置之后动态获取当前数据源 */
private boolean dynamicDataSource = false;
/* Count优化方式 */
private String optimizeType = "default";
/* 方言类型 */
private String dialectType;
/* 方言实现类 */
private String dialectClazz;
/**
* Physical Pagination Interceptor for all the queries with parameter {@link org.apache.ibatis.session.RowBounds}
*/
public Object intercept(Invocation invocation) throws Throwable {
StatementHandler statementHandler = (StatementHandler) PluginUtils.realTarget(invocation.getTarget());
MetaObject metaStatementHandler = SystemMetaObject.forObject(statementHandler);
// 先判断是不是SELECT操作
MappedStatement mappedStatement = (MappedStatement) metaStatementHandler.getValue("delegate.mappedStatement");
if (!SqlCommandType.SELECT.equals(mappedStatement.getSqlCommandType())) {
return invocation.proceed();
}
RowBounds rowBounds = (RowBounds) metaStatementHandler.getValue("delegate.rowBounds");
/* 不需要分页的场合 */
if (rowBounds == null || rowBounds == RowBounds.DEFAULT) {
return invocation.proceed();
}
BoundSql boundSql = (BoundSql) metaStatementHandler.getValue("delegate.boundSql");
String originalSql = boundSql.getSql();
Connection connection = (Connection) invocation.getArgs()[0];
if (isDynamicDataSource()) {
dialectType = JdbcUtils.getDbType(connection.getMetaData().getURL()).getDb();
}
if (rowBounds instanceof Pagination) {
Pagination page = (Pagination) rowBounds;
boolean orderBy = true;
if (page.isSearchCount()) {
CountOptimize countOptimize = SqlUtils.getCountOptimize(originalSql, optimizeType, dialectType, page.isOptimizeCount());
orderBy = countOptimize.isOrderBy();
this.queryTotal(countOptimize.getCountSQL(), mappedStatement, boundSql, page, connection);
if (page.getTotal() <= 0) {
return invocation.proceed();
}
}
String buildSql = SqlUtils.concatOrderBy(originalSql, page, orderBy);
originalSql = DialectFactory.buildPaginationSql(page, buildSql, dialectType, dialectClazz);
} else {
// support physical Pagination for RowBounds
originalSql = DialectFactory.buildPaginationSql(rowBounds, originalSql, dialectType, dialectClazz);
}
/*
* <p> 禁用内存分页 </p> <p> 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。</p>
*/
metaStatementHandler.setValue("delegate.boundSql.sql", originalSql);
metaStatementHandler.setValue("delegate.rowBounds.offset", RowBounds.NO_ROW_OFFSET);
metaStatementHandler.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(String sql, MappedStatement mappedStatement, BoundSql boundSql, Pagination page, Connection connection) {
try (PreparedStatement statement = connection.prepareStatement(sql)) {
DefaultParameterHandler parameterHandler = new MybatisDefaultParameterHandler(mappedStatement, boundSql.getParameterObject(), boundSql);
parameterHandler.setParameters(statement);
int total = 0;
try (ResultSet resultSet = statement.executeQuery()) {
if (resultSet.next()) {
total = resultSet.getInt(1);
}
}
page.setTotal(total);
/*
* 溢出总页数,设置第一页
*/
int pages = page.getPages();
if (overflowCurrent && (page.getCurrent() > pages)) {
page = new Pagination(1, page.getSize());
page.setTotal(total);
}
} catch (Exception e) {
logger.error("Error: Method queryTotal execution error !", e);
}
}
public Object plugin(Object target) {
if (target instanceof StatementHandler) {
return Plugin.wrap(target, this);
}
return target;
}
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;
}
}
public void setDialectType(String dialectType) {
this.dialectType = dialectType;
}
public void setDialectClazz(String dialectClazz) {
this.dialectClazz = dialectClazz;
}
public void setOverflowCurrent(boolean overflowCurrent) {
this.overflowCurrent = overflowCurrent;
}
public void setOptimizeType(String optimizeType) {
this.optimizeType = optimizeType;
}
public boolean isDynamicDataSource() {
return dynamicDataSource;
}
public void setDynamicDataSource(boolean dynamicDataSource) {
this.dynamicDataSource = dynamicDataSource;
}
}