com.baomidou.mybatisplus.extension.plugins.pagination.DialectFactory Maven / Gradle / Ivy
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/*
* Copyright (c) 2011-2014, 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.pagination;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import org.apache.ibatis.session.RowBounds;
import com.baomidou.mybatisplus.annotation.DbType;
import com.baomidou.mybatisplus.core.metadata.IPage;
import com.baomidou.mybatisplus.core.toolkit.Assert;
import com.baomidou.mybatisplus.core.toolkit.ExceptionUtils;
import com.baomidou.mybatisplus.core.toolkit.StringUtils;
import com.baomidou.mybatisplus.extension.plugins.pagination.dialects.DB2Dialect;
import com.baomidou.mybatisplus.extension.plugins.pagination.dialects.DmDialect;
import com.baomidou.mybatisplus.extension.plugins.pagination.dialects.H2Dialect;
import com.baomidou.mybatisplus.extension.plugins.pagination.dialects.HSQLDialect;
import com.baomidou.mybatisplus.extension.plugins.pagination.dialects.IDialect;
import com.baomidou.mybatisplus.extension.plugins.pagination.dialects.MariaDBDialect;
import com.baomidou.mybatisplus.extension.plugins.pagination.dialects.MySqlDialect;
import com.baomidou.mybatisplus.extension.plugins.pagination.dialects.OracleDialect;
import com.baomidou.mybatisplus.extension.plugins.pagination.dialects.PostgreDialect;
import com.baomidou.mybatisplus.extension.plugins.pagination.dialects.SQLServer2005Dialect;
import com.baomidou.mybatisplus.extension.plugins.pagination.dialects.SQLServerDialect;
import com.baomidou.mybatisplus.extension.plugins.pagination.dialects.SQLiteDialect;
/**
*
* 分页方言工厂类
*
*
* @author hubin
* @since 2016-01-23
*/
public class DialectFactory {
/**
* 方言缓存
*/
private static final Map DIALECT_CACHE = new ConcurrentHashMap<>();
/**
*
* 生成翻页执行 SQL
*
*
* @param page 翻页对象
* @param buildSql 执行 SQL
* @param dbType 数据库类型
* @param dialectClazz 自定义方言实现类
* @return
* @throws Exception
*/
public static String buildPaginationSql(Page page, String buildSql, DbType dbType, String dialectClazz)
throws Exception {
// fix #172, 196
return getDialect(dbType, dialectClazz).buildPaginationSql(buildSql, offsetCurrent(page), page.getSize());
}
/**
*
* Page 分页偏移量
*
*/
public static long offsetCurrent(IPage page) {
if (null == page) {
return 0;
}
return offsetCurrent(page.getCurrent(), page.getSize());
}
/**
*
* 计算当前分页偏移量
*
*
* @param current 当前页
* @param size 每页显示数量
* @return
*/
public static long offsetCurrent(long current, long size) {
if (current > 0) {
return (current - 1) * size;
}
return 0;
}
/**
* Physical Page Interceptor for all the queries with parameter
* {@link RowBounds}
*
* @param page 翻页对象
* @param buildSql 编译 SQL
* @param dbType 数据类型
* @param dialectClazz 数据库方言
* @return
* @throws Exception
*/
public static String buildPaginationSql(IPage page, String buildSql, DbType dbType, String dialectClazz)
throws Exception {
// fix #196
return getDialect(dbType, dialectClazz).buildPaginationSql(buildSql, page.offset(), page.getSize());
}
/**
*
* 获取数据库方言
*
*
* @param dbType 数据库类型
* @param dialectClazz 自定义方言实现类
* @return
* @throws Exception
*/
private static IDialect getDialect(DbType dbType, String dialectClazz) throws Exception {
IDialect dialect = DIALECT_CACHE.get(dbType.getDb());
if (null == dialect) {
// 自定义方言
if (StringUtils.isNotEmpty(dialectClazz)) {
dialect = DIALECT_CACHE.get(dialectClazz);
if (null != dialect) {
return dialect;
}
try {
Class clazz = Class.forName(dialectClazz);
if (IDialect.class.isAssignableFrom(clazz)) {
dialect = (IDialect) clazz.newInstance();
DIALECT_CACHE.put(dialectClazz, dialect);
}
} catch (ClassNotFoundException e) {
throw ExceptionUtils.mpe("Class :" + dialectClazz + " is not found");
}
} else {
// 缓存方言
dialect = getDialectByDbType(dbType);
DIALECT_CACHE.put(dbType.getDb(), dialect);
}
/* 未配置方言则抛出异常 */
Assert.notNull(dialect, "The value of the dialect property in mybatis configuration.xml is not defined.");
}
return dialect;
}
/**
*
* 根据数据库类型选择不同分页方言
*
*
* @param dbType 数据库类型
* @return
* @throws Exception
*/
private static IDialect getDialectByDbType(DbType dbType) {
if (dbType == DbType.MYSQL) {
return new MySqlDialect();
}
if (dbType == DbType.MARIADB) {
return new MariaDBDialect();
}
if (dbType == DbType.ORACLE) {
return new OracleDialect();
}
if (dbType == DbType.DB2) {
return new DB2Dialect();
}
if (dbType == DbType.H2) {
return new H2Dialect();
}
if (dbType == DbType.SQL_SERVER) {
return new SQLServerDialect();
}
if (dbType == DbType.SQL_SERVER2005) {
return new SQLServer2005Dialect();
}
if (dbType == DbType.POSTGRE_SQL) {
return new PostgreDialect();
}
if (dbType == DbType.HSQL) {
return new HSQLDialect();
}
if (dbType == DbType.SQLITE) {
return new SQLiteDialect();
}
if (dbType == DbType.DM) {
return new DmDialect();
}
throw ExceptionUtils.mpe("The Database's Not Supported! DBType:" + dbType);
}
}