查詢數據庫時直接封住成List>格式
最近研究項目查詢底層使用的dao時發現了一個比較好用的封裝類，在查詢數據庫時，可以將查詢出來的字段直接封裝成key-value模式，即，key是字段名，value是字段對應的值，固然是一個map<String,String>表明一行數據/對象，多個對象在一個list中，代碼以下：java
import java.lang.reflect.Method;
import java.sql.CallableStatement;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Statement;
import java.sql.Timestamp;
import java.sql.Types;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.List;
import org.apache.log4j.Logger;
import org.hibernate.HibernateException;
import org.hibernate.Session;
import org.springframework.orm.hibernate3.HibernateCallback;
import org.springframework.orm.hibernate3.SessionFactoryUtils;
import org.springframework.stereotype.Repository;
import com.minxinloan.common.utils.DateTimeUtils;
import com.minxinloan.common.utils.SystemConstant;
import com.minxinloan.dao.JdbcDao;
/**
* Created with IntelliJ IDEA.
* User: Administrator
* Date: 13-10-21
* Time: 下午1:24
* To change this template use File | Settings | File Templates.
*/
public class JdbcDaoImpl extends BaseDaoImpl implements JdbcDao{
private final static Logger log = Logger.getLogger(JdbcDaoImpl.class);
/**
* get data from the ResultSet which is save in the given colnum and type
*
* @param rs
* @param colNum
* @param type
* @return
* @throws SQLException
*/
private Object getValue(final ResultSet rs, int colNum, int type)
throws SQLException {
switch (type) {
case Types.ARRAY:
case Types.BLOB:
// case Types.CLOB:
case Types.DISTINCT:
case Types.LONGVARBINARY:
case Types.VARBINARY:
case Types.BINARY:
case Types.REF:
case Types.STRUCT:
return null;
default: {
Object value = rs.getObject(colNum);
if (rs.wasNull() || (value == null))
return null;
else
return value;
}
}
}
/**
* change a ResultSet to ArrayList if the data in ResultSet is null then
* save it as a default string
*
* @param resultSet
* @param strDefalut
* @param transType "MAP"-every record translate to HashMap,"LIST"-every record translate to ArrayList
* @return
* @throws SQLException
*/
public ArrayList FromResultToArrayList(ResultSet resultSet,String strDefalut,String transType) {
ArrayList dataList = new ArrayList();
if (resultSet == null)
return dataList;
try {
// get the strut of the ResultSet
ResultSetMetaData resultmd = resultSet.getMetaData();
if (resultmd == null)
return dataList;
// get the total count of column
int colCount = resultmd.getColumnCount();
// deal with all data one by one
while (resultSet.next()) {
Object row = null;
if ("MAP".equalsIgnoreCase(transType)){
row = new HashMap();
}else{
row = new ArrayList(colCount);
}
for (int i = 1; i <= colCount; i++) {
// get type of column
int type = resultmd.getColumnType(i);
String colName = resultmd.getColumnName(i);
// get data
if ("MAP".equalsIgnoreCase(transType)){
((HashMap)row).put(colName.toUpperCase(), ObjectToString(getValue(resultSet, i, type),
strDefalut));
}else{
((ArrayList)row).add(ObjectToString(getValue(resultSet, i, type),
strDefalut));
}
}
dataList.add(row);
}
} catch (SQLException e) {
log.error(e);
}
return dataList;
}
static public Object convertClobColumn(Object value) throws Exception {
if (value != null) {
if (value.getClass().getName().toLowerCase().contains("clob")) {
StringBuilder sb = new StringBuilder();
long clenl = (Long) new Object() {
Method getMethod(Object obj) throws Exception {
Method method = null;
method = obj.getClass().getMethod("length", null);
return method;
}
}.getMethod(value).invoke(value, null);
int bufl = 4096;
bufl = bufl < clenl ? bufl : (int) clenl;
int rcount = 0;
for (long l = 1; l <= clenl; l += bufl) {
rcount = (int) (clenl - l + 1);
rcount = rcount < bufl ? rcount : bufl;
sb.append(new Object() {
Method getMethod(Object obj) throws Exception {
Method method = null;
method = obj.getClass().getMethod("getSubString",
long.class, int.class);
return method;
}
}.getMethod(value).invoke(value, l, rcount));
}
value = sb.toString();
}
}
return value;
}
/**
* change the object to String type
*
* @param obj
* @param strDefalut
* @return
*/
private String ObjectToString(Object obj, String strDefalut) {
if (obj == null)
return strDefalut;
String strResult = strDefalut;
// date type java.sql.Date
if (obj instanceof java.sql.Date) {
strResult = DateTimeUtils.DateToString((java.sql.Date) obj,
SystemConstant.CURR_JAVA_DATE_FORMATTER, strDefalut);
// date type java.sql.T
} else if (obj instanceof Timestamp) {
strResult = DateTimeUtils.TimestampToString(
(java.sql.Timestamp) obj,
SystemConstant.CURR_JAVA_DATETIME_FORMATTER, strDefalut);
// numeral type
} else if (obj instanceof java.math.BigDecimal) {
strResult = ((java.math.BigDecimal) obj).toString();
}else if(obj.getClass().getName().toLowerCase().contains("clob")){
try{
obj=convertClobColumn(obj);
}catch(Exception e){e.printStackTrace();}
strResult=obj==null?"":obj.toString();
} else {
strResult = obj.toString();
}
if (strResult != null)
strResult = strResult.trim();
return strResult;
}
private String ObjectToString(Object obj) {
return ObjectToString(obj, "");
}
/**
* 從數據庫獲取查詢結果
* @param sql
* @param encapType
* @return
* @see queryData(final String sql,final String encapType,final List params)
*/
public List queryData(final String sql,final String encapType){
return queryData(sql,encapType,null);
}
/**
* 從數據庫獲取查詢結果
* @param sql
* @param encapType: 查詢結果封裝方式MAP/LIST
* @param params: 參數列表
* @return
*/
public List queryData(final String sql,final String encapType,final List params){
return (List) getHibernateTemplate().execute(new HibernateCallback() {
public Object doInHibernate(Session session) throws HibernateException, SQLException {
PreparedStatement pst = null;
ResultSet rs = null;
ArrayList resultList = null;
Connection conn = null;
try {
conn = session.connection();
pst = conn.prepareStatement(sql, ResultSet.TYPE_SCROLL_INSENSITIVE,
ResultSet.CONCUR_READ_ONLY);
if(params!=null){
for (int i = 0; i<params.size(); i++){
Object obj = params.get(i);
if (obj instanceof Integer){
pst.setInt(i+1, ((Integer)obj).intValue());
}else if (obj instanceof Long){
pst.setLong(i+1, ((Long)obj).longValue());
}else if (obj instanceof Double){
pst.setDouble(i+1, ((Double)obj).doubleValue());
}else if (obj instanceof Float){
pst.setFloat(i+1, ((Float)obj).floatValue());
}else if (obj instanceof java.util.Date){
pst.setDate(i+1, (java.sql.Date)obj);
}else if (obj instanceof java.sql.Date){
pst.setDate(i+1, (java.sql.Date)obj);
}else if (obj instanceof String){
pst.setString(i+1, (String)obj);
}else{
pst.setObject(i+1, obj);
}
}
}
rs = pst.executeQuery();
resultList = FromResultToArrayList(rs,SystemConstant.DEFAULTNNULLVAL,encapType);
} catch (SQLException e) {
log.error(e.getMessage(),e);
log.error("sql："+sql+"————————encapType:"+encapType+"————————params:"+params);
} finally {
closeResultSet(rs);
closeStatement(pst);
}
return resultList;
}
});
}
public List queryData(String sql){
return queryData(sql,"LIST");
}
public List queryDataOfMapEncap(String sql){
return queryData(sql,"MAP");
}
/**
* 得到查詢的結果總數
* @param conn
* @param originalSql
* @return
*/
public int getTotalCount(final String sql){
Integer iResult = (Integer) getHibernateTemplate().execute(new HibernateCallback() {
public Object doInHibernate(Session session) throws HibernateException, SQLException {
Connection conn = null;
int iRes = 0;
ResultSet rs = null;
PreparedStatement pst = null;
String newSQL = "SELECT COUNT(*) FROM (" + sql + ") a";
try {
conn = session.connection();
pst = conn.prepareStatement(newSQL,
ResultSet.TYPE_SCROLL_INSENSITIVE,
ResultSet.CONCUR_READ_ONLY);
rs = pst.executeQuery();
if (rs.next())
iRes = rs.getInt(1);
} catch (SQLException e) {
log.error(e);
} finally {
closeResultSet(rs);
closeStatement(pst);
}
return new Integer(iRes);
}
});
return iResult.intValue();
}
protected void closeResultSet(ResultSet result) {
if (result != null) {
try {
result.close();
} catch (Exception e) {
}
}
result = null;
}
protected void closeStatement(Statement st) {
if (st != null) {
try {
st.close();
} catch (Exception e) {
}
}
st = null;
}
protected void closeConnection(Connection conn) {
if (conn != null) {
try {
conn.close();
} catch (Exception e) {
}
}
conn = null;
}
public int execute(final String sql){
Integer iResult = (Integer) getHibernateTemplate().execute(new HibernateCallback() {
public Object doInHibernate(Session session) throws HibernateException, SQLException {
int returnVal = 0;
PreparedStatement statement = null;
try{
Connection conn = session.connection();
statement = conn.prepareStatement(sql);
returnVal = statement.executeUpdate();
return new Integer(returnVal);
}finally{
closeStatement(statement);
}
}
});
return iResult.intValue();
}
public int updateAndCommit(final String sql){
Integer iResult = (Integer) getHibernateTemplate().execute(new HibernateCallback() {
public Object doInHibernate(Session session) throws HibernateException, SQLException {
int returnVal = 0;
PreparedStatement statement = null;
try{
Connection conn = session.connection();
statement = conn.prepareStatement(sql);
returnVal = statement.executeUpdate();
conn.commit();
return new Integer(returnVal);
}finally{
closeStatement(statement);
}
}
});
return iResult.intValue();
}
public String executeProc(final String procName){
String iResult = (String) getHibernateTemplate().execute(new HibernateCallback() {
public Object doInHibernate(Session session) throws HibernateException, SQLException {
String returnVal = "";
CallableStatement statement = null;
try{
Connection conn = session.connection();
statement = conn.prepareCall(procName);
statement.registerOutParameter(1, Types.VARCHAR);
statement.execute();
returnVal = statement.getString(1);
return returnVal;
}finally{
closeStatement(statement);
}
}
});
return iResult;
}
/**
*
* @return
* @throws Exception
*/
public Connection getConnection() throws Exception{
return SessionFactoryUtils.getDataSource(getSessionFactory()).getConnection();
}
/**
*
*/
public String getCommaSQL(String sql){
String result=null;
List list=queryData(sql);
if(list.size()>0){
List tmp=(List)list.get(0);
result=tmp.get(0).toString();
}
return result;
}
@Override
public void saveOrUpdateAll(List pos) {
// TODO Auto-generated method stub
getHibernateTemplate().saveOrUpdateAll(pos);
}
/**
* 批量插入的方法
* @param sql 執行的sql
* @param argss 參數
* @return
* @throws Exception
*/
@Override
public int[] batchExecuteSql(final String sql, final Collection<Object[]> argss) throws Exception {
return (int[]) getHibernateTemplate().execute(new HibernateCallback() {
public Object doInHibernate(Session session)throws HibernateException, SQLException {
int[] rvl = null;
PreparedStatement stmt = null;
try {
Connection conn = session.connection();
stmt = conn.prepareStatement(sql);
stmt.clearBatch();
for (Object[] args : argss) {
if (args != null && args.length > 0) {
for(int i = 0; i < args.length; ++i){
stmt.setObject(i + 1, args[i]);
}
stmt.addBatch();
}
}
rvl = stmt.executeBatch();
} catch (SQLException e) {
throw e;
} finally {
if (stmt != null)
stmt.close();
}
return rvl;
}
});
}
這裏使用的hibernate+jdbc一塊兒的。spring
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