Database connection classes for Java common tool classes (can connect to multiple databases)
- 2020-04-01 03:21:07
- OfStack
Dependent package download: (link: http://xiazai.jb51.net/201407/tools/java-db-dependency (jb51.net). Rar)
Database connection class source code:
package com.itjh.javaUtil;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.apache.commons.dbcp.ConnectionFactory;
import org.apache.commons.dbcp.DriverManagerConnectionFactory;
import org.apache.commons.dbcp.PoolableConnectionFactory;
import org.apache.commons.dbcp.PoolingDriver;
import org.apache.commons.dbutils.DbUtils;
import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.MapListHandler;
import org.apache.commons.pool.ObjectPool;
import org.apache.commons.pool.impl.GenericObjectPool;
/**
* A comprehensive class that connects to a database. </br>
* Rely on jar Package: commons.dbcp-1.4 . commons.dbutils-1.3 . commons.pool-1.5.4 The package.
*
* @author Song Lijun
* @date 2014 years 07 month 03 day
*/
public class DBUtil {
private String dri = null;
private String url = null;
private String username = null;
private String password = null;
private String poolName = null; //Connection pool name
private ObjectPool connectionPool = null; //The connection pool
//The corresponding timed query class
private QueryThread queryThread = null;
/**
* Function: constructor
*
* @author Song Lijun
* @date 2014 years 07 month 03 day
* @param dri
* Driver full class name, for example: com.mysql.jdbc.Driver .
* @param url
* The database url Links, such as:
* "jdbc:mysql://127.0.0.1:3306/test?autoReconnect=true&useUnicode=true&characterEncoding=UTF-8"
* @param userName
* Database user name, for example: root
* @param password
* Database password, for example: abc
* @param poolName
* The name of the database connection pool created, for example mypool , notice one web Container this name cannot be repeated.
*/
public DBUtil(String dri, String url, String userName, String password,
String poolName) {
this.dri = dri;
this.url = url;
this.username = userName;
this.password = password;
this.poolName = poolName;
}
public int execute(Connection conn, PreparedStatement pstm)
throws SQLException {
try {
return pstm.executeUpdate();
} finally {
Close(conn);
}
}
public List<Map<String, Object>> query(Connection conn,
PreparedStatement pstm) throws SQLException {
try {
return resultSetToList(pstm.executeQuery());
} finally {
Close(conn);
}
}
private List<Map<String, Object>> resultSetToList(ResultSet rs)
throws java.sql.SQLException {
if (rs == null)
return Collections.EMPTY_LIST;
ResultSetMetaData md = rs.getMetaData(); //Get the result set (rs) structure information, such as the number of fields, field names, and so on
int columnCount = md.getColumnCount(); //Returns the number of columns in this ResultSet object
List<Map<String, Object>> list = new ArrayList<Map<String, Object>>();
Map<String, Object> rowData = new HashMap<String, Object>();
while (rs.next()) {
rowData = new HashMap<String, Object>(columnCount);
for (int i = 1; i <= columnCount; i++) {
rowData.put(md.getColumnName(i), rs.getObject(i));
}
list.add(rowData);
}
return list;
}
public List<Map<String, Object>> query(String sql) throws SQLException {
List<Map<String, Object>> results = null;
Connection conn = null;
try {
conn = getConnection();
QueryRunner qr = new QueryRunner();
results = qr.query(conn, sql, new MapListHandler());
} finally {
Close(conn);
}
return results;
}
public List<Map<String, Object>> query(String sql, Object param)
throws SQLException {
List<Map<String, Object>> results = null;
Connection conn = null;
try {
conn = getConnection();
QueryRunner qr = new QueryRunner();
results = (List<Map<String, Object>>) qr.query(conn, sql, param,
new MapListHandler());
} catch (SQLException e) {
e.printStackTrace();
} finally {
Close(conn);
}
return results;
}
public int execute(String sql) throws Exception {
Connection conn = getConnection();
int rows = 0;
try {
QueryRunner qr = new QueryRunner();
rows = qr.update(conn, sql);
} finally {
Close(conn);
}
return rows;
}
public int execute(String sql, Object[] params) throws Exception {
Connection conn = getConnection();
int rows = 0;
try {
QueryRunner qr = new QueryRunner();
rows = qr.update(conn, sql, params);
} finally {
Close(conn);
}
return rows;
}
public void Close(Connection conn) throws SQLException {
if (conn != null) {
conn.close();
}
DbUtils.closeQuietly(conn);
}
private void StartPool() {
try {
Class.forName(dri);
} catch (ClassNotFoundException e1) {
e1.printStackTrace();
}
if (connectionPool != null) {
ShutdownPool();
}
try {
connectionPool = new GenericObjectPool(null);
ConnectionFactory connectionFactory = new DriverManagerConnectionFactory(
url, username, password);
PoolableConnectionFactory poolableConnectionFactory = new PoolableConnectionFactory(
connectionFactory, connectionPool, null, "SELECT 1", false,
true);
Class.forName("org.apache.commons.dbcp.PoolingDriver");
PoolingDriver driver = (PoolingDriver) DriverManager
.getDriver("jdbc:apache:commons:dbcp:");
driver.registerPool(poolName, poolableConnectionFactory.getPool());
} catch (Exception e) {
e.printStackTrace();
}
//Open query program
queryThread = new QueryThread(this);
queryThread.start();
}
private void ShutdownPool() {
try {
PoolingDriver driver = (PoolingDriver) DriverManager
.getDriver("jdbc:apache:commons:dbcp:");
driver.closePool(poolName);
//Closing timed queries
queryThread.setStartQuery(false);
} catch (SQLException e) {
e.printStackTrace();
}
}
public synchronized Connection getConnection() {
Connection conn = null;
try {
if (connectionPool == null)
StartPool();
conn = DriverManager.getConnection("jdbc:apache:commons:dbcp:"
+ poolName);
} catch (Exception e) {
e.printStackTrace();
}
return conn;
}
}
class QueryThread extends Thread {
private DBUtil dbUtil = null;
//Whether to open a query
private boolean startQuery = true;
public QueryThread(DBUtil dbUtil) {
this.dbUtil = dbUtil;
}
public void run() {
while (true) {
try {
if (startQuery) {
this.dbUtil.query("select 1");
}
// System.out.println(startQuery+" 123");
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
Thread.sleep(120000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
public void setStartQuery(boolean startQuery) {
// System.out.println("startQuery shut:"+startQuery);
this.startQuery = startQuery;
}
}