Java tutorial
/** * Copyright © 2012-2013 <a href="https://github.com/thinkgem/jeesite">JeeSite</a> All rights reserved. * * Licensed under the Apache License, Version 2.0 (the "License"); */ package com.sjtu.icare.common.persistence.interceptor; import org.apache.ibatis.executor.ErrorContext; import org.apache.ibatis.executor.ExecutorException; import org.apache.ibatis.logging.Log; import org.apache.ibatis.mapping.BoundSql; import org.apache.ibatis.mapping.MappedStatement; import org.apache.ibatis.mapping.ParameterMapping; import org.apache.ibatis.mapping.ParameterMode; import org.apache.ibatis.reflection.MetaObject; import org.apache.ibatis.reflection.SystemMetaObject; import org.apache.ibatis.reflection.property.PropertyTokenizer; import org.apache.ibatis.scripting.xmltags.ForEachSqlNode; import org.apache.ibatis.session.Configuration; import org.apache.ibatis.type.TypeHandler; import org.apache.ibatis.type.TypeHandlerRegistry; import com.sjtu.icare.common.persistence.Page; import com.sjtu.icare.common.persistence.dialect.Dialect; import com.sjtu.icare.common.utils.StringUtils; import java.sql.Connection; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; import java.util.List; import java.util.regex.Matcher; import java.util.regex.Pattern; /** * SQL * @author poplar.yfyang / thinkgem * @version 2013-8-28 */ public class SQLHelper { /** * SQL?(?),?org.apache.ibatis.executor.parameter.DefaultParameterHandler * * @param ps SQL ? * @param mappedStatement MappedStatement * @param boundSql SQL * @param parameterObject ? * @throws java.sql.SQLException ? */ @SuppressWarnings("unchecked") public static void setParameters(PreparedStatement ps, MappedStatement mappedStatement, BoundSql boundSql, Object parameterObject) throws SQLException { ErrorContext.instance().activity("setting parameters").object(mappedStatement.getParameterMap().getId()); List<ParameterMapping> parameterMappings = boundSql.getParameterMappings(); if (parameterMappings != null) { Configuration configuration = mappedStatement.getConfiguration(); TypeHandlerRegistry typeHandlerRegistry = configuration.getTypeHandlerRegistry(); MetaObject metaObject = parameterObject == null ? null : configuration.newMetaObject(parameterObject); for (int i = 0; i < parameterMappings.size(); i++) { ParameterMapping parameterMapping = parameterMappings.get(i); if (parameterMapping.getMode() != ParameterMode.OUT) { Object value; String propertyName = parameterMapping.getProperty(); PropertyTokenizer prop = new PropertyTokenizer(propertyName); if (parameterObject == null) { value = null; } else if (typeHandlerRegistry.hasTypeHandler(parameterObject.getClass())) { value = parameterObject; } else if (boundSql.hasAdditionalParameter(propertyName)) { value = boundSql.getAdditionalParameter(propertyName); } else if (propertyName.startsWith(ForEachSqlNode.ITEM_PREFIX) && boundSql.hasAdditionalParameter(prop.getName())) { value = boundSql.getAdditionalParameter(prop.getName()); if (value != null) { value = configuration.newMetaObject(value) .getValue(propertyName.substring(prop.getName().length())); } } else { value = metaObject == null ? null : metaObject.getValue(propertyName); } @SuppressWarnings("rawtypes") TypeHandler typeHandler = parameterMapping.getTypeHandler(); if (typeHandler == null) { throw new ExecutorException("There was no TypeHandler found for parameter " + propertyName + " of statement " + mappedStatement.getId()); } typeHandler.setParameter(ps, i + 1, value, parameterMapping.getJdbcType()); } } } } /** * * @param sql SQL? * @param connection ? * @param mappedStatement mapped * @param parameterObject ? * @param boundSql boundSql * @return * @throws SQLException sql */ public static int getCount(final String sql, final Connection connection, final MappedStatement mappedStatement, final Object parameterObject, final BoundSql boundSql, Log log) throws SQLException { // final String countSql = "select count(1) from (" + sql + ") tmp_count"; final String countSql = "select count(1) " + removeSelect(removeOrders(sql)); Connection conn = connection; PreparedStatement ps = null; ResultSet rs = null; try { if (log.isDebugEnabled()) { log.debug("COUNT SQL: " + StringUtils.replaceEach(countSql, new String[] { "\n", "\t" }, new String[] { " ", " " })); } if (conn == null) { conn = mappedStatement.getConfiguration().getEnvironment().getDataSource().getConnection(); } ps = conn.prepareStatement(countSql); BoundSql countBS = new BoundSql(mappedStatement.getConfiguration(), countSql, boundSql.getParameterMappings(), parameterObject); //?metaParameters.. MetaObject countBsObject = SystemMetaObject.forObject(countBS); MetaObject boundSqlObject = SystemMetaObject.forObject(boundSql); countBsObject.setValue("metaParameters", boundSqlObject.getValue("metaParameters")); SQLHelper.setParameters(ps, mappedStatement, countBS, parameterObject); rs = ps.executeQuery(); int count = 0; if (rs.next()) { count = rs.getInt(1); } return count; } finally { if (rs != null) { rs.close(); } if (ps != null) { ps.close(); } if (conn != null) { conn.close(); } } } /** * ???sql * @param sql MapperSql? * @param page * @param dialect * @return SQL */ public static String generatePageSql(String sql, Page<Object> page, Dialect dialect) { if (dialect.supportsLimit()) { return dialect.getLimitString(sql, page.getFirstResult(), page.getMaxResults()); } else { return sql; } } /** * qlStringselect?? * @param qlString * @return */ private static String removeSelect(String qlString) { int beginPos = qlString.toLowerCase().indexOf("from"); return qlString.substring(beginPos); } /** * hqlorderBy?? * @param qlString * @return */ private static String removeOrders(String qlString) { Pattern p = Pattern.compile("order\\s*by[\\w|\\W|\\s|\\S]*", Pattern.CASE_INSENSITIVE); Matcher m = p.matcher(qlString); StringBuffer sb = new StringBuffer(); while (m.find()) { m.appendReplacement(sb, ""); } m.appendTail(sb); return sb.toString(); } }