导读：
主要从4个方面来阐述，1：背景；2：思路；3：代码实现；4：使用
一：封装背景，
在做项目的时候，用的JPA ，有些复杂查询，比如报表用原生的JdbcTemplate ，很不方便；需要增加分页功能，以及结果集自动转对像等5个常用功能，见第4节。
下面两个图是开源测试管理软件 itest 的统计功能，因为SQL复杂，有些有200行，所以才有后面的 JdbcTemplateWrapper；可以在这体验这些报表（点测试，然后选择一个项目，然后点度量分析），速度还不错，https://itest.work/demo/login.htm
上面这图，SQL 就有200行
二：封装实现思路
（1）实现spring RowMapper 接口，直接把jdbc 结果集转 JAVA 对像(用的反射，访问量大的业务不推荐用这方式)
（2）不通过 RowMapper 接口, 把JdbcTemplate 返回的List<Map<String,Object>> 原生JDBC结果集中，字段名，也就是MAP中的KEY，转换为驼峰规则的JAVA对属性名,方便前端组件使用，不再中间转为VO 或 实体类对像后，再返前端;比传统查询（多了一个LIST的遍历 ，基本对性能影响不大）
（3）封装分页
三：代码实现
两个类，ObjectRowMapper 和 JdbcTemplateWrapper
ObjectRowMapper 代码如下：
1 package cn.com.mypm.framework.jdbc; 2 3 import java.lang.reflect.Field; 4 import java.sql.ResultSet; 5 import java.sql.ResultSetMetaData; 6 import java.sql.SQLException; 7 import java.util.HashMap; 8 import java.util.Map; 9 import java.util.concurrent.ConcurrentHashMap; 10 11 import org.apache.commons.logging.Log; 12 import org.apache.commons.logging.LogFactory; 13 import org.springframework.jdbc.core.RowMapper; 14 import org.springframework.util.StringUtils; 15 16 import cn.com.mypm.common.util.CalendaUtilities; 17 import cn.com.mypm.framework.common.config.PropertiesBean; 18 19 20 21 /** 22 * 23 * <p>标题: RowMapper 接口实现</p> 24 * <p>业务描述:完成原生结果集到JAVA对像的转换</p> 25 * <p>公司:itest.work</p> 26 * <p>版权:itest 2018</p> 27 * @author itest andy 28 * @date 2018年6月8日 29 * @version V1.0 30 */ 31 @SuppressWarnings("rawtypes") 32 public class ObjectRowMapper implements RowMapper { 33 34 35 private Class<?> objectClass; 36 private String[] columnNames = null; 37 private Field[] fields ; 38 ///缓存 当前结果集字对段和当前class的 Field的对应关系， 39 private Map<String ,Field> currQueryFieldMap ; 40 //缓存当前结果集，字段和 JAVA属性名的对应关系 ，按脱峰规则做的转换 41 private Map<String ,String> fieldClassMap ; 42 private Boolean isConvertSwitch = null; 43 // MYSQL 是否区分大小写的标记，要是区转，要把结果集中，字段名，大写转为小写 44 private String mysqlLowerCaseTableNames = null; 45 private static Log logger = LogFactory.getLog(ObjectRowMapper.class); 46 //缓存某个class 已处理过的字段映射到属性名的关系，避免同一个类每次重新处理，第一个KEY 为类名 47 private static Map<String, Map<String, String>> dbColumnClassFieldMap = new ConcurrentHashMap<String, Map<String, String>>(); 48 49 public ObjectRowMapper(Class<?> objectClass) { 50 this.objectClass = objectClass; 51 fields = objectClass.getDeclaredFields(); 52 } 53 54 public void clean(){ 55 if(currQueryFieldMap!=null){ 56 currQueryFieldMap.clear(); 57 currQueryFieldMap = null; 58 } 59 if(fieldClassMap!=null){ 60 fieldClassMap.clear(); 61 fieldClassMap = null; 62 } 63 if(fields!=null){ 64 fields = null; 65 } 66 if(columnNames!=null){ 67 columnNames = null; 68 } 69 } 70 71 /** 72 * 该方法自动将数据库字段对应到Object中相应字段 要求： 73 * 字段名严格为驼峰形式 == 数据库字段名去掉下划线转为驼峰形式 74 * 如user_name 转为userName ，如数据库字段名，无下划线 75 * 就只能把首字母变为大小写后的 set ,get 76 */ 77 @Override 78 public Object mapRow(ResultSet rs, int rowNum) throws SQLException { 79 80 Object targetObject = null; 81 try { 82 targetObject = objectClass.newInstance(); 83 } catch (InstantiationException | IllegalAccessException e) { 84 logger.error(e.getMessage(), e); 85 } 86 if (columnNames == null) { 87 ResultSetMetaData rsmd = rs.getMetaData(); 88 int columnCount = rsmd.getColumnCount(); 89 columnNames = new String[columnCount]; 90 for (int i = 0; i < columnCount; i++) { 91 columnNames[i] = rsmd.getColumnLabel(i + 1); 92 } 93 } 94 isConvertSwitch = true; 95 96 if(mysqlLowerCaseTableNames == null){ 97 String lowerCaseNames = PropertiesBean.getInstance().getProperty("conf.mysql.lowerCaseNames"); 98 if(lowerCaseNames==null){ 99 mysqlLowerCaseTableNames = "yes"; 100 }else{ 101 mysqlLowerCaseTableNames = "no"; 102 } 103 } 104 if(currQueryFieldMap==null){ 105 currQueryFieldMap = new HashMap<String,Field>(columnNames.length); 106 for (String columnName : columnNames) { 107 for (Field field : fields) { 108 if(isConvertSwitch==null){ 109 if (field.getName().equals( 110 convertColumnNameToFieldName(columnName))) { 111 currQueryFieldMap.put(columnName, field); 112 break; 113 } 114 }else{ 115 if(isConvertSwitch){ 116 if(targetObject instanceof CustomRowMapper&&(!((CustomRowMapper)targetObject).isConvert())){ 117 if (field.getName().equals(columnName)) { 118 currQueryFieldMap.put(columnName, field); 119 break; 120 } 121 }else{ 122 if (field.getName().equals( 123 convertColumnNameToFieldName(columnName))) { 124 currQueryFieldMap.put(columnName, field); 125 break; 126 } 127 } 128 } 129 130 } 131 132 } 133 } 134 } 135 for (String columnName : columnNames) { 136 Field field = currQueryFieldMap.get(columnName); 137 if(field==null){ 138 if(logger.isDebugEnabled()){ 139 logger.debug(objectClass.getName() +"is not property match db columnName:"+columnName ); 140 } 141 continue; 142 } 143 Object value = rs.getObject(columnName); 144 if (value == null) { 145 continue; 146 } 147 boolean accessFlag = field.isAccessible(); 148 if (!accessFlag) { 149 field.setAccessible(true); 150 } 151 if(fieldClassMap==null){ 152 fieldClassMap = new HashMap<String,String>(columnNames.length); 153 } 154 if(fieldClassMap.get(columnName)==null){ 155 fieldClassMap.put(columnName, getFieldClaszName(field)); 156 } 157 setFieldValue(targetObject, field, rs, columnName,fieldClassMap.get(columnName)); 158 // 恢复相应field的权限 159 if (!accessFlag) { 160 field.setAccessible(accessFlag); 161 } 162 } 163 return targetObject; 164 } 165 166 167 public String convertColumnNameToFieldName(String columnName) { 168 169 Map<String, String> fieldMap = dbColumnClassFieldMap.get(objectClass 170 .getName()); 171 boolean emptyFlg = false; 172 if (fieldMap == null) { 173 fieldMap = new HashMap<String, String>(); 174 emptyFlg = true; 175 } 176 177 String classFieldName = fieldMap.get(columnName); 178 if (classFieldName != null) { 179 return classFieldName; 180 } 181 String columnNameKey = columnName; 182 183 //if ("oracle".equals(dbType)||("mysql".equals(dbType)&&"no".equals(mysqlLowerCaseTableNames))) { 184 columnName = columnName.toLowerCase(); 185 //} 186 187 StringBuffer buf = new StringBuffer(); 188 int i = 0; 189 while ((i = columnName.indexOf('_')) > 0) { 190 buf.append(columnName.substring(0, i)); 191 columnName = StringUtils.capitalize(columnName.substring(i + 1)); 192 } 193 buf.append(columnName); 194 fieldMap.put(columnNameKey, buf.toString()); 195 if (emptyFlg) { 196 dbColumnClassFieldMap.put(objectClass.getName(), fieldMap); 197 } 198 return fieldMap.get(columnNameKey); 199 } 200 201 /** 202 * 根据类型对具体对象属性赋值 203 */ 204 public static void setFieldValue(Object targetObj, Field field, 205 ResultSet rs, String columnLabel,String fieldClass) { 206 207 try { 208 if ("String".equals(fieldClass)) { 209 field.set(targetObj, rs.getString(columnLabel)); 210 } else if ("Double".equals(fieldClass)) { 211 field.set(targetObj, rs.getDouble(columnLabel)); 212 } else if ("Float".equals(fieldClass)) { 213 field.set(targetObj, rs.getFloat(columnLabel)); 214 } else if ("Integer".equals(fieldClass)) { 215 field.set(targetObj, rs.getInt(columnLabel)); 216 } else if ("Long".equals(fieldClass)) { 217 field.set(targetObj, rs.getLong(columnLabel)); 218 } else if ("BigDecimal".equals(fieldClass)) { 219 field.set(targetObj, rs.getBigDecimal(columnLabel)); 220 } else if ("Date".equals(fieldClass)) { 221 field.set(targetObj, rs.getDate(columnLabel)); 222 } else if ("Short".equals(fieldClass)) { 223 field.set(targetObj, rs.getShort(columnLabel)); 224 } else if ("Boolean".equals(fieldClass)) { 225 field.set(targetObj, rs.getBoolean(columnLabel)); 226 } else if ("Byte".equals(fieldClass)) { 227 field.set(targetObj, rs.getByte(columnLabel)); 228 } else if ("Timestamp".equals(fieldClass)) { 229 field.set(targetObj, rs.getTimestamp(columnLabel)); 230 } else if("BigDecimal".equals(fieldClass)) { 231 field.set(targetObj, rs.getBigDecimal(columnLabel)); 232 }else { 233 //这里没有实现，如有特殊需要处理的在这里实现 234 } 235 236 } catch (IllegalArgumentException e) { 237 logger.error(e.getMessage(), e); 238 } catch (IllegalAccessException e) { 239 logger.error(e.getMessage(), e); 240 } catch (SQLException e) { 241 logger.error(e.getMessage(), e); 242 } 243 } 244 245 private static String getFieldClaszName(Field field) { 246 247 String elemType = field.getType().toString(); 248 if ("class java.lang.String".equals(elemType) 249 || elemType.indexOf("char") != -1 250 || elemType.indexOf("Character") != -1) { 251 return "String"; 252 } else if (elemType.indexOf("double") != -1 253 || elemType.indexOf("Double") != -1) { 254 return "Double"; 255 } else if (elemType.indexOf("float") != -1 256 || elemType.indexOf("Float") != -1) { 257 return "Float"; 258 } else if (elemType.indexOf("int") != -1 259 || elemType.indexOf("Integer") != -1||elemType.indexOf("BigInteger") != -1) { 260 return "Integer"; 261 } else if (elemType.indexOf("long") != -1 262 || elemType.indexOf("Long") != -1) { 263 return "Long"; 264 } else if (elemType.indexOf("BigDecimal") != -1) { 265 return "BigDecimal"; 266 } else if (elemType.indexOf("Date") != -1) { 267 return "Date"; 268 } else if (elemType.indexOf("short") != -1 269 || elemType.indexOf("Short") != -1) { 270 return "Short"; 271 } else if (elemType.indexOf("boolean") != -1 272 || elemType.indexOf("Boolean") != -1) { 273 return "Boolean"; 274 } else if (elemType.indexOf("byte") != -1 275 || elemType.indexOf("Byte") != -1) { 276 return "Byte"; 277 } else if (elemType.indexOf("Timestamp") != -1) { 278 return "Timestamp"; 279 } 280 281 return "String"; 282 283 }
JdbcTemplateWrapper
package cn.com.mypm.framework.jdbc; import java.util.ArrayList; import java.util.HashMap; import java.util.Iterator; import java.util.List; import java.util.Map; import java.util.Map.Entry; import java.util.Set; import java.util.regex.Matcher; import java.util.regex.Pattern; import org.apache.commons.lang3.StringUtils; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.springframework.jdbc.core.JdbcTemplate; import org.springframework.jdbc.core.RowMapper; import org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate; import org.springframework.util.Assert; import cn.com.mypm.common.dto.PageModel; import cn.com.mypm.framework.exception.DataBaseException; /** * * <p>标题: JdbcTemplate 包装器</p> * <p>业务描述:实现分页，原生结果集转对像，原生结果集字段名转脱峰java 属性名</p> * <p>公司:itest.work</p> * <p>版权:itest 2018</p> * @author itest andy * @date 2018年6月8日 * @version V1.0 */ public class JdbcTemplateWrapper { private static Log logger = LogFactory.getLog(JdbcTemplateWrapper.class); private JdbcTemplate jdbcTemplate; private String dbType = "mysql"; private String showSql = "false"; protected NamedParameterJdbcTemplate namedParameterJdbcTemplate; private String mysqlLowerCaseTableNames = null; public JdbcTemplateWrapper() { super(); } public JdbcTemplateWrapper(JdbcTemplate jdbcTemplate) { super(); this.jdbcTemplate = jdbcTemplate; this.namedParameterJdbcTemplate = new NamedParameterJdbcTemplate(jdbcTemplate); } public JdbcTemplateWrapper(JdbcTemplate jdbcTemplate, String dbType, String showSql) { super(); this.jdbcTemplate = jdbcTemplate; this.dbType = dbType; this.namedParameterJdbcTemplate = new NamedParameterJdbcTemplate(jdbcTemplate); this.showSql = showSql; } public JdbcTemplate getJdbcTemplate() { return jdbcTemplate; } /** * 查询所有匹配的列表 * * @param sql * 查询sql * @param className * 对象类型 * @param args * 查询参数 * @return * @author itest andy */ @SuppressWarnings({ "rawtypes", "unchecked" }) public List queryAllMatchList(String sql, Class clasz, Object[] args) { Assert.notNull(clasz, "clasz must not be null"); List dataList = null; RowMapper rowMapper = new ObjectRowMapper(clasz); dataList = getJdbcTemplate().query(sql, args, rowMapper); ((ObjectRowMapper) rowMapper).clean(); rowMapper = null; return dataList; } /** * 查询所有匹配的列表 * * @param sql * 查询sql * @param className * 对象类型 * @param args * 查询参数 * @return * @author itest andy */ @SuppressWarnings({ "rawtypes", "unchecked" }) public List queryAllMatchListWithFreePra(String sql, Class clasz, Object... args) { Assert.notNull(clasz, "clasz must not be null"); List dataList = null; RowMapper rowMapper = new ObjectRowMapper(clasz); dataList = getJdbcTemplate().query(sql, args, rowMapper); ((ObjectRowMapper) rowMapper).clean(); rowMapper = null; return dataList; } /** * 把list map 原生JDBC结果集中，字段名，也就是MAP中的KEY，转换为驼峰规则的JAVA对属性名 * * @param resultList ：JDBC 结果集 * @return 把MAP中的KEY转换为转换为驼峰规则的JAVA对属性名的LIST<map<驼峰规则的JAVA对属性名形式的KEY,Object>> * @author itest andy */ public void converDbColumnName2ObjectPropName(List<Map<String,Object>> resultList) { if(resultList!=null&&!resultList.isEmpty()) { List<Map<String,Object>> convertList= new ArrayList<Map<String,Object>>(resultList.size()); //用于缓存字段名到属性名的映射，第二条记录时就不再处理字段名到属性名的转换，提升性能 Map<String,String> ColumnNamePropNameMap = null; if(resultList.size()>1) { ColumnNamePropNameMap = new HashMap<String,String>(); } for(Map<String,Object> currMap :resultList) { if(currMap!=null&&!currMap.isEmpty()) { Iterator<Entry<String, Object>> currentIt = currMap.entrySet().iterator(); Map tempMap = new HashMap<String,Object>(); convertList.add(tempMap); while(currentIt.hasNext()) { Map.Entry<String,Object> me= currentIt.next(); String dbColumnName = me.getKey(); Object value = me.getValue(); if(resultList.size()>1) { if(ColumnNamePropNameMap.get(dbColumnName)==null) { String currProName = convertColumnName2OFieldName(dbColumnName); tempMap.put(currProName, value); //缓存起来，第二条记录时就不再处理字段名到属性名的转换，提升性能 ColumnNamePropNameMap.put(dbColumnName, currProName); }else { tempMap.put(ColumnNamePropNameMap.get(dbColumnName), value); } }else { tempMap.put(convertColumnName2OFieldName(dbColumnName), value); } } } } resultList.clear(); for(Map<String,Object> currMap:convertList) { resultList.add(currMap); } convertList.clear(); convertList = null; } } public String convertColumnName2OFieldName(String columnName ) { if(mysqlLowerCaseTableNames == null){ String lowerCaseNames = PropertiesBean.getInstance().getProperty("conf.mysql.lowerCaseNames"); if(lowerCaseNames==null){ mysqlLowerCaseTableNames = "yes"; }else{ mysqlLowerCaseTableNames = "no"; } } if ("oracle".equals(dbType)||("mysql".equals(dbType)&&"no".equals(mysqlLowerCaseTableNames))) { columnName = columnName.toLowerCase(); } if("true".equals(mysqlLowerCaseTableNames)) { columnName = columnName.toLowerCase(); } StringBuffer buf = new StringBuffer(); int i = 0; while ((i = columnName.indexOf('_')) > 0) { buf.append(columnName.substring(0, i)); columnName = StringUtils.capitalize(columnName.substring(i + 1)); } buf.append(columnName); return buf.toString(); } /** * 查询所有匹配的列表 * * @param sql * 查询sql * @param className * 对象类型 * @param paramMap * 查询参数 * @return * @author itest andy */ @SuppressWarnings({ "rawtypes", "unchecked" }) public List queryAllMatchListWithParaMap(String sql, Class clasz, Map paramMap) { if (paramMap != null && paramMap.isEmpty()) { paramMap = null; } if ("true".equals(showSql)) { try { logger.info(getSqlFromQueryData(sql, paramMap)); } catch (Exception e) { logger.error(e.getMessage(), e); } } List resultList = null; if (clasz == null) { resultList = namedParameterJdbcTemplate.queryForList(sql, paramMap); } else { RowMapper rowMapper = new ObjectRowMapper(clasz); resultList = namedParameterJdbcTemplate.query(sql, paramMap, rowMapper); ((ObjectRowMapper) rowMapper).clean(); rowMapper = null; } return resultList; } /** * * @param pageModel: * @param className * : 从查询结果集中构建出的类，如为null则pageModel的PageData为List<Map>， * 不为null则pageModel的PageData为List<className> * @param columnNameForCount:查询记录数时的字段名，一般用主键 */ @SuppressWarnings({ "rawtypes", "unchecked" }) public void fillPageModelData(PageModel pageModel, Class className, String columnNameForCount) { if (pageModel.getHqlParamMap() != null && pageModel.getHqlParamMap().isEmpty()) { pageModel.setHqlParamMap(null); } if (pageModel.getTotal() == 0) { int totalRows = this.getResultCountWithValuesMap(pageModel.getQueryHql(), columnNameForCount, pageModel.getHqlParamMap()); pageModel.setTotal(totalRows); } if (pageModel.getTotal() == 0) { pageModel.setRows(new ArrayList()); return; } if (pageModel.getPageNo() > 1) { int pageCount = this.getValidPage(pageModel.getPageNo(), pageModel.getTotal(), pageModel.getPageSize()); if (pageCount < pageModel.getPageNo()) { pageModel.setPageNo(pageCount); } } int startRow = getStartOfPage(pageModel.getPageNo(), pageModel.getPageSize()); String sql = this.buildPageSql(pageModel.getQueryHql(), startRow, pageModel.getPageSize()); if ("true".equals(showSql)) { try { logger.info(getSqlFromQueryData(sql, pageModel.getHqlParamMap())); } catch (Exception e) { logger.error(e.getMessage(), e); } } List dataList = null; if (className == null) { dataList = namedParameterJdbcTemplate.queryForList(sql, pageModel.getHqlParamMap()); } else { RowMapper rowMapper = new ObjectRowMapper(className); dataList = namedParameterJdbcTemplate.query(sql, pageModel.getHqlParamMap(), rowMapper); ((ObjectRowMapper) rowMapper).clean(); rowMapper = null; } pageModel.setRows(dataList); } /** * 多表sql 分页查询,多表连查时，才用这个方法，其他请用commonDao的 SQL分页查询 * * @param sql * @param className * @param paramMap * @param pageNo * @param PageSize * @param columnNameForCount * @return */ @SuppressWarnings({ "rawtypes", "unchecked" }) public List queryAllMatchListWithParaMap(String sql, Class clasz, Map paramMap, int pageNo, int pageSize, String columnNameForCount) { if (paramMap != null && paramMap.isEmpty()) { paramMap = null; } if ("true".equals(showSql)) { try { logger.info(getSqlFromQueryData(sql, paramMap)); } catch (Exception e) { logger.error(e.getMessage(), e); } } // int totalRows = this.getResultCountWithValuesMap(sql, // columnNameForCount, paramMap); // if(pageNo>1){ // int pageCount = this.getValidPage(pageNo, totalRows, pageSize); // } List resultList = null; int startRow = getStartOfPage(pageNo, pageSize); if (clasz == null) { resultList = namedParameterJdbcTemplate.queryForList(this.buildPageSql(sql, startRow, pageSize), paramMap); } else { RowMapper rowMapper = new ObjectRowMapper(clasz); resultList = namedParameterJdbcTemplate.query(this.buildPageSql(sql, startRow, pageSize), paramMap, rowMapper); rowMapper = null; } return resultList; } private String buildPageSql(String sql, int startRow, int pageSize) { if ("oracle".equals(this.getDbType())) { return this.buildOraclePageSql(sql, startRow, pageSize); } else if ("mysql".equals(this.getDbType())) { return this.buildMysqlPageSql(sql, startRow, pageSize); } else if ("informix".equals(this.getDbType())) { return this.buildInformixPageSql(sql, startRow, pageSize); } throw new DataBaseException("don't support db type,please confirm db is oracle or mysql or informix"); } private String buildOraclePageSql(String sql, int startRow, int pageSize) { StringBuilder pageSql = new StringBuilder("SELECT * FROM "); pageSql.append(" ( "); pageSql.append(" SELECT pageDataTable.*, ROWNUM RNV "); pageSql.append(" FROM (" + sql + " ) pageDataTable "); pageSql.append(" WHERE ROWNUM <= " + (startRow + pageSize)); pageSql.append(" ) WHERE RNV >= " + (startRow + 1)); return pageSql.toString(); } private String buildMysqlPageSql(String sql, int startRow, int pageSize) { sql = sql + " limit " + startRow + ", " + pageSize; return sql; } private String buildInformixPageSql(String sql, int startRow, int pageSize) { sql = sql.trim(); if (sql.startsWith("select")) { sql = sql.replaceFirst("select", " select skip " + startRow + " first " + pageSize + " "); } else { sql = sql.replaceFirst("SELECT", " select skip " + startRow + " first " + pageSize + " "); } return sql; } private Integer getValidPage(Integer pageNo, int totalRows, Integer pageSize) { if (!isValidPage(pageNo, totalRows, pageSize)) { return getValidPage(--pageNo, totalRows, pageSize); } int pageCount = (totalRows + (pageSize - (totalRows % pageSize == 0 ? pageSize : totalRows % pageSize))) / pageSize; return pageCount; } private static int getStartOfPage(int pageNo, int pageSize) { if(pageNo==0){ pageNo=1; } return (pageNo - 1) * pageSize; } private boolean isValidPage(Integer pageNo, Integer totalRows, Integer pageSize) { if (pageNo == 1) { return true; } int rowStart = (pageNo - 1) * pageSize; int rowEnd = rowStart + pageSize; if (rowEnd > totalRows) { rowEnd = totalRows; } return rowEnd > rowStart; } /** * 查询记录数 * * @param sql * @param columnNameForCount * @param praValuesMap * @return */ // @SuppressWarnings("deprecation") public int getResultCountWithValuesMap(String sql, String columnNameForCount, Map<String, Object> praValuesMap) { if (praValuesMap != null && praValuesMap.isEmpty()) { praValuesMap = null; } String countQuerySql = null; countQuerySql = " select count(*) from ( " + sql + " ) V_TABLE"; return namedParameterJdbcTemplate.queryForInt(countQuerySql, praValuesMap); } public int queryForIntWithpraValuesMap(String countQuerySql, Map<String, Object> praValuesMap) { if (praValuesMap != null && praValuesMap.isEmpty()) { praValuesMap = null; } return namedParameterJdbcTemplate.queryForInt(countQuerySql, praValuesMap); } public int queryForInt(String countQuerySql, Object... args) { return getJdbcTemplate().queryForInt(countQuerySql, args); } public static String getSqlFromQueryData(String sql, Map<String, Object> paramMap) { if (StringUtils.isEmpty(sql)) { return null; } if (paramMap == null) { return sql; } StringBuffer sqlExp = new StringBuffer(sql); Set<Entry<String, Object>> set = paramMap.entrySet(); for (Entry<String, Object> entry : set) { int start = sqlExp.indexOf(":" + entry.getKey() + " "); if (start < 0) { continue; } int last = sqlExp.lastIndexOf(":" + entry.getKey() + " "); if (start >= 0 && start == last) { if (entry.getValue() != null) { sqlExp.replace(start, start + entry.getKey().length(), "'" + entry.getValue().toString() + "'"); // sqlExp.replace(start-1, start+entry.getKey().length(), // "'"+entry.getValue().toString()+"'"); } } else { // 处理同一参数多处出现 sqlExp.replace(start, start + entry.getKey().length(), "'" + entry.getValue().toString() + "'"); start = sqlExp.indexOf(":" + entry.getKey()); while (start > 0) { sqlExp.replace(start, start + entry.getKey().length(), "'" + entry.getValue().toString() + "'"); start = sqlExp.indexOf(":" + entry.getKey()); } } } return sqlExp.toString(); } private static String removeSelect(String sql) { int beginPos = sql.indexOf(" from "); if (beginPos < 0) { beginPos = sql.indexOf("from "); } if (beginPos < 0) { beginPos = sql.toLowerCase().indexOf(" from "); } if (beginPos < 0) { beginPos = sql.toLowerCase().indexOf("from "); } return sql.substring(beginPos); } /** * 去除sql的orderby 用于页查果询 * * @param sql * @return */ private static String removeOrders(String sql) { Pattern p = Pattern.compile("order\\s*by[\\w|\\W|\\s|\\S]*", Pattern.CASE_INSENSITIVE); Matcher m = p.matcher(sql); StringBuffer sb = new StringBuffer(); while (m.find()) { m.appendReplacement(sb, ""); } m.appendTail(sb); return sb.toString(); } public String getDbType() { return dbType; } public NamedParameterJdbcTemplate getNamedParameterJdbcTemplate() { return namedParameterJdbcTemplate; } public void setJdbcTemplate(JdbcTemplate jdbcTemplate) { this.jdbcTemplate = jdbcTemplate; this.namedParameterJdbcTemplate = new NamedParameterJdbcTemplate(jdbcTemplate); } public String getMysqlLowerCaseTableNames() { return mysqlLowerCaseTableNames; } public void setMysqlLowerCaseTableNames(String mysqlLowerCaseTableNames) { this.mysqlLowerCaseTableNames = mysqlLowerCaseTableNames; } public String isShowSql() { return showSql; } public void setShowSql(String showSql) { this.showSql = showSql; } }
三：使用
数据源和JPA是同一数据源，在同一事务中，用的连接和JPA使用的是同一个连接，在CommonDao 额外注入一个 JdbcTemplateWrapper,当作处理复杂SQL的帮手。
JdbcTemplateWrapper 常用的方法同如下几个：
clasz 把查询结果要转为的类对像，内部再构造 ObjectRowMapper
1：public List queryAllMatchListWithFreePra(String sql, Class clasz, Object... args) // SQL 参数为问号占位符，使用参数个数<=3 个时的情况,可以用要不参数多了，可变长参数多，阅读性差
2：public List queryAllMatchListWithParaMap(String sql, Class clasz, Map paramMap) // SQL 参数，为 参数名占位符 ,如 name=:name, paramMap中 key 为参数名，value 为值数值(用于参数个数多于3时，用参数名占位符的方式，然后用Map 传参) ; 如clasz 传为为空，实际返为 List<Map<String,Object>>,不为空侧为 List<Map<String,clasz>>
3： 以pageModel为载体实现分页
/**
*
* @param pageModel: 设置了查询SQL ，及查询参数 Map paramMap 的分页对像
* @param className
* : 从查询结果集中构建出的类，如为null则pageModel的PageData为List<Map>，
* 不为null则pageModel的PageData为List<className>
* @param columnNameForCount:查询记录数时的字段名，一般用主键
*/
@SuppressWarnings({ "rawtypes", "unchecked" })
public void fillPageModelData(PageModel pageModel, Class className)
4 ： 不用 pageModel 分页查询
/**
* 多表sql 分页查询,多表连查时，才用这个方法，其他请用commonDao的 SQL分页查询
*
* @param sql
* @param className
* @param paramMap
* @param pageNo
* @param PageSize
* @param columnNameForCount
* @return
*/
@SuppressWarnings({ "rawtypes", "unchecked" })
public List queryAllMatchListWithParaMap(String sql, Class clasz, Map paramMap, int pageNo, int pageSize)
5 ： 把list map 原生JDBC结果集中，字段名，也就是MAP中的KEY，转换为驼峰规则的JAVA对属性名
/**
* 把list map 原生JDBC结果集中，字段名，也就是MAP中的KEY，转换为驼峰规则的JAVA对属性名
* 方便前端组件使用，不再中间转为VO 或 实体类对像后，再返前端;比传统查询（多了一个LIST的遍历 ，基本对性能影响不大）
* @param resultList ：JDBC 结果集
* @return 把MAP中的KEY转换为转换为驼峰规则的JAVA对属性名的LIST<map<驼峰规则的JAVA对属性名形式的KEY,Object>>
* @author itest andy
*/
public void converDbColumnName2ObjectPropName(List<Map<String,Object>> resultList)