* 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.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.enums.DBType; import com.baomidou.mybatisplus.plugins.pagination.DialectFactory; import com.baomidou.mybatisplus.plugins.pagination.PageHelper; import com.baomidou.mybatisplus.plugins.pagination.Pagination; import com.baomidou.mybatisplus.plugins.parser.ISqlParser; import com.baomidou.mybatisplus.plugins.parser.SqlInfo; import com.baomidou.mybatisplus.toolkit.JdbcUtils; import com.baomidou.mybatisplus.toolkit.PluginUtils; import com.baomidou.mybatisplus.toolkit.SqlUtils; import com.baomidou.mybatisplus.toolkit.StringUtils; /** *
* 分页拦截器 *
* * @author hubin * @Date 2016-01-23 */ @Intercepts({@Signature(type = StatementHandler.class, method = "prepare", args = {Connection.class, Integer.class})}) public class PaginationInterceptor extends SqlParserHandler implements Interceptor { // 日志 private static final Log logger = LogFactory.getLog(PaginationInterceptor.class); // COUNT SQL 解析 private ISqlParser sqlParser; /* 溢出总页数，设置第一页 */ private boolean overflowCurrent = false; /* 方言类型 */ private String dialectType; /* 方言实现类 */ private String dialectClazz; /* 是否开启 PageHelper localPage 模式 */ private boolean localPage = false; /** * Physical Pagination Interceptor for all the queries with parameter {@link org.apache.ibatis.session.RowBounds} */ @Override public Object intercept(Invocation invocation) throws Throwable { StatementHandler statementHandler = (StatementHandler) PluginUtils.realTarget(invocation.getTarget()); MetaObject metaObject = SystemMetaObject.forObject(statementHandler); 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(); } RowBounds rowBounds = (RowBounds) metaObject.getValue("delegate.rowBounds"); /* 不需要分页的场合 */ if (rowBounds == null || rowBounds == RowBounds.DEFAULT) { // 本地线程分页 if (localPage) { // 采用ThreadLocal变量处理的分页 rowBounds = PageHelper.getPagination(); if (rowBounds == null) { return invocation.proceed(); } } else { // 无需分页 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"); String originalSql = boundSql.getSql(); Connection connection = (Connection) invocation.getArgs()[0]; DBType dbType = StringUtils.isNotEmpty(dialectType) ? DBType.getDBType(dialectType) : JdbcUtils.getDbType(connection.getMetaData().getURL()); if (rowBounds instanceof Pagination) { Pagination page = (Pagination) rowBounds; boolean orderBy = true; if (page.isSearchCount()) { SqlInfo sqlInfo = SqlUtils.getCountOptimize(sqlParser, originalSql); orderBy = sqlInfo.isOrderBy(); this.queryTotal(overflowCurrent, sqlInfo.getSql(), mappedStatement, boundSql, page, connection); if (page.getTotal() <= 0) { return invocation.proceed(); } } String buildSql = SqlUtils.concatOrderBy(originalSql, page, orderBy); originalSql = DialectFactory.buildPaginationSql(page, buildSql, dbType, dialectClazz); } else { // support physical Pagination for RowBounds originalSql = DialectFactory.buildPaginationSql(rowBounds, originalSql, 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, 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)) { // 设置为第一条 page.setCurrent(1); } } catch (Exception e) { logger.error("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"); String localPage = prop.getProperty("localPage"); if (StringUtils.isNotEmpty(dialectType)) { this.dialectType = dialectType; } if (StringUtils.isNotEmpty(dialectClazz)) { this.dialectClazz = dialectClazz; } if (StringUtils.isNotEmpty(localPage)) { this.localPage = Boolean.valueOf(localPage); } } public PaginationInterceptor setDialectType(String dialectType) { this.dialectType = dialectType; return this; } public PaginationInterceptor setDialectClazz(String dialectClazz) { this.dialectClazz = dialectClazz; return this; } public PaginationInterceptor setOverflowCurrent(boolean overflowCurrent) { this.overflowCurrent = overflowCurrent; return this; } public PaginationInterceptor setSqlParser(ISqlParser sqlParser) { this.sqlParser = sqlParser; return this; } public PaginationInterceptor setLocalPage(boolean localPage) { this.localPage = localPage; return this; } }