/**
* Copyright 2014 Liang Yuan
* 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;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.Date;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Timestamp;
import java.util.ArrayList;
import java.util.List;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.sql.DataSource;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
public class DBConnection {
/** Hold the class name to be used in logging. */
private static final String CLASS_NAME = DBConnection.class.getName();
private static Log log = LogFactory.getLog(DBConnection.class);
private static javax.naming.Context ctx = null;
private static String jndi = "java:/comp/env/jdbc/subsidy";
private static final String BATCH_SIZE = ApplicationConfig
.getInstance().getConfigValue("batch_size");
private static void createInitialCxt(){
try{
ctx = new InitialContext();
} catch(NamingException ne){
}
}
public static synchronized Connection getConnection(){
Connection conn = null;
if (ctx == null) {
createInitialCxt();
}
try{
DataSource ds = (DataSource)ctx.lookup(jndi);
conn = ds.getConnection();
} catch(NamingException ne){
ne.printStackTrace();
} catch(SQLException se){
se.printStackTrace();;
}
return conn;
}
/**
* return a connection.
*
* @return database connection.
* @throws SQLException
* if the database connection cannot be fetched.
*/
public Connection getConnection(String databaseDriver, String connectString, String databaseUser, String databasePwd) throws SQLException {
log.debug("Enter method getConnection");
Connection conn = null;
try {
Class.forName(databaseDriver);
conn = DriverManager.getConnection(connectString, databaseUser, databasePwd);
} catch (Throwable ex) {
String errmsg = MessageFormatHelper.getMessage(LogMessage.CLASS_NOTFOUND_ERROR, new Object[] { CLASS_NAME,
"getConnection", databaseDriver });
log.error(errmsg, ex);
throw new InvalidConfigurationException(errmsg, ex);
}
log.debug(MessageFormatHelper.getMessage(LogMessage.METHOD_EXIT, new Object[] { CLASS_NAME, "getConnection",
" <" + conn + ">" }));
return conn;
}
/**
* Executes a JDBC update using a prepared statement.
*
* @param sql
* the sql statement to be executed.
* @param params
* The parameters for the SQL, must be in the order specified in
* the SQL.
* @throws SQLException
* if database connection cannot be fetched or sql statement
* cannot be executed.
*/
public void executeUpdate(String sql, Object[] params) throws SQLException {
log.debug("Enter method executeUpdate, sql <" + sql + ">," + MessageFormatHelper.getArrayAsString("params", params));
Connection conn = null;
PreparedStatement stmt = null;
conn = getConnection();
try {
stmt = conn.prepareStatement(sql);
setParam(stmt, params);
stmt.executeUpdate();
} catch (SQLException e) {
String errmsg = "SQLException happened when executing <sql>: " + sql + "," + MessageFormatHelper.getArrayAsString("params", params) + "please see log file for more details.";
log.error(errmsg, e);
throw e;
} finally {
// Close the prepared statement and the connection, even if an
// exception is thrown.
if (stmt != null) {
try {
stmt.close();
} catch (SQLException e) {
String warnmsg = "Error happened during closing statement";
log.warn(warnmsg, e);
}
}
if (conn != null) {
try {
conn.close();
} catch (SQLException e) {
String warnmsg = "Error happened when closing the database connection";
log.warn(warnmsg, e);
}
}
}
log.debug("Exit method executeUpdate");
}
public void executeBatchUpdate(String sql, List<Object[]> paramList) throws SQLException {
log.debug("Enter method executeBatchUpdate, sql <" + sql + ">");
Connection conn = null;
PreparedStatement stmt = null;
conn = getConnection();
boolean autoCommit = conn.getAutoCommit();
conn.setAutoCommit(false);
int errRowNum = 0;
try {
stmt = conn.prepareStatement(sql);
for (int loop = 0, batchCount = 0; loop < paramList.size(); loop++, batchCount++) {
Object[] params = paramList.get(loop);
setParam(stmt, params);
stmt.addBatch();
errRowNum = loop;
if (batchCount == Integer.parseInt(BATCH_SIZE)) {
stmt.executeBatch();
stmt.clearBatch();
batchCount = 0;
conn.commit();
}
}
stmt.executeBatch();
conn.commit();
} catch (SQLException e) {
String errmsg = "SQLException happened when batch executing <sql>: " + sql + ", error occurs around records[" + errRowNum + "], please check whether these records have error";
log.error(errmsg, e);
throw new FatalException(errmsg, e);
} finally {
// Close the prepared statement and the connection, even if an
// exception is thrown.
if (stmt != null) {
try {
stmt.close();
} catch (SQLException e) {
String warnmsg = "Error happened during closing statement";
log.warn(warnmsg, e);
}
}
if (conn != null) {
try {
conn.setAutoCommit(autoCommit);
conn.close();
} catch (SQLException e) {
String warnmsg = "Error happened when closing the database connection";
log.warn(warnmsg, e);
}
}
}
log.debug("Exit method executeBatchUpdate");
}
/**
* Executes a JDBC query using a prepared statement.
*
* @param sql
* The SQL to be executed.
* @param params
* The parameters for the SQL, must be in the order specified in
* the SQL.
* @param returnTypes
* The type of the data to be returned, in the order in which the
* SQL returns them.
* @return An array of objects of the type specified in returnTypes.
* @throws SQLException
* if database connection cannot be fetched or sql statement
* cannot be executed.
*/
public Object[][] executeQuery(String sql, Object[] params, int[] returnTypes) throws SQLException {
log.debug("Enter method executeQuery, sql <" + sql + ">," + MessageFormatHelper.getArrayAsString("params", params) + ">, returnTypes <" + returnTypes + ">");
Object[][] returnValues = null;
Connection conn = null;
PreparedStatement stmt = null;
conn = getConnection();
try {
stmt = conn.prepareStatement(sql);
setParam(stmt, params);
ResultSet rs = stmt.executeQuery();
returnValues = getReturnValues(rs, returnTypes);
} catch (SQLException e) {
String errmsg = "SQLException happened when executing <sql>: " + sql + "," + MessageFormatHelper.getArrayAsString("params", params) + "please see log file for more details.";
log.error(errmsg, e);
throw e;
} finally {
// Close the prepared statement and the connection, even if an
// exception is thrown.
if (stmt != null) {
try {
stmt.close();
} catch (SQLException e) {
String warnmsg = "Error happened during closing statement";
log.warn(warnmsg, e);
}
}
if (conn != null) {
try {
conn.close();
} catch (SQLException e) {
String warnmsg = "Error happened when closing the database connection";
log.warn(warnmsg, e);
}
}
}
log.debug(" Exit method executeQuery");
return returnValues;
}
/**
* Sets the supplied parameters in the prepared statement.
*
* @param stmt
* the sql statement
* @param params
* the needed parameters.
* @throws SQLException
* if database error happen.
*
*/
private void setParam(PreparedStatement stmt, Object[] params) throws SQLException {
for (int i = 0; i < params.length; i++) {
if (params[i] == null) {
stmt.setString(i + 1, null);
} else if (params[i] instanceof String) {
stmt.setString(i + 1, (String) params[i]);
} else if (params[i] instanceof Double) {
stmt.setDouble(i + 1, ((Double) params[i]).doubleValue());
} else if (params[i] instanceof java.sql.Date) {
stmt.setDate(i + 1, (Date) params[i]);
} else if (params[i] instanceof Timestamp) {
stmt.setTimestamp(i + 1, (Timestamp) params[i]);
} else if (params[i] instanceof java.util.Date) {
java.util.Date date = (java.util.Date) params[i];
stmt.setDate(i + 1, new java.sql.Date(date.getTime()));
} else if (params[i] instanceof Integer) {
stmt.setInt(i + 1, ((Integer) params[i]).intValue());
} else if (params[i] instanceof Long) {
stmt.setLong(i + 1, ((Long) params[i]).longValue());
} else if (params[i] instanceof InputStream) {
stmt.setBinaryStream(i + 1, (InputStream) params[i]);
} else {
stmt.setString(i + 1, params[i].toString());
}
}
}
/**
* Gets the return data fromt he result set, using the returnTypes.
*
* @param rs
* result set from database.
* @param returnTypes
* type list.
* @throws SQLException
* if the database errors happen.
* @return object arrays.
*/
private Object[][] getReturnValues(ResultSet rs, int[] returnTypes) throws SQLException {
ArrayList returnValues = new ArrayList();
while (rs.next()) {
Object[] rowValues = new Object[returnTypes.length];
for (int i = 0; i < returnTypes.length; i++) {
if (returnTypes[i] == DataConstant.STRING) {
rowValues[i] = rs.getString(i + 1);
} else if (returnTypes[i] == DataConstant.INT) {
rowValues[i] = new Integer(rs.getInt(i + 1));
} else if (returnTypes[i] == DataConstant.DOUBLE) {
rowValues[i] = new Double(rs.getDouble(i + 1));
} else if (returnTypes[i] == DataConstant.DATE) {
rowValues[i] = rs.getDate(i + 1);
} else if (returnTypes[i] == DataConstant.TIMESTAMP) {
rowValues[i] = rs.getTimestamp(i + 1);
} else if (returnTypes[i] == DataConstant.LONG) {
rowValues[i] = new Long(rs.getLong(i + 1));
}
}
returnValues.add(rowValues);
}
Object[][] returnObject = (Object[][]) returnValues.toArray(new Object[0][0]);
return returnObject;
}
}
DB Connection
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