jdbc连接mysql数据库封装类

/**
 * mysql数据库操作
*/
package database;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;

/**
 * @author Qutr
 *
 */
public class DbConnection
{
private Connection dbConnection = null;
private Statement selectPro = null; //用于 select 操作
private Statement updatePro = null; //用于 update 操作
private ResultSet dbResultSet = null; //操作 select 结果集

private String driverName;//声明MySql驱动类
private String dbHost;
private String dbPort;
private String dbName;
private String dbUserName;
private String dbPassword;
private String enCoding;

/**
 * 实例化DbConnection对象
 * @param host 数据库主机（IP）
 * @param port 数据库端口
 * @param dName 数据库名称
 * @param uName 用户名
 * @param password 用户密码
 */
public DbConnection(String host, String port, String dName, String uName, String password)
{
driverName = "com.mysql.jdbc.Driver";
dbHost = host;
dbPort = port;
dbName = dName;
dbUserName = uName;
dbPassword = password;
enCoding = "?useUnicode=true&characterEncoding=gb2312&autoReconnect=true";
}//end DbConnection(...)

/**
 * 连接数据库
 * @return 连接成功返回true，连接失败返回false
 */
public boolean dbConnection()
{
StringBuilder urlTem = new StringBuilder();
urlTem.append("jdbc:mysql://");
urlTem.append(dbHost);
urlTem.append(":");
urlTem.append(dbPort);
urlTem.append("/");
urlTem.append(dbName);
urlTem.append(enCoding);
String url = urlTem.toString();
try
{
Class.forName(driverName).newInstance();
dbConnection = DriverManager.getConnection(url, dbUserName, dbPassword);
return true;
}catch(Exception e){
System.err.println("数据库联接失败！");
System.out.println("url = " + url);
e.printStackTrace(); //得到详细的出错消息
return false;
}
}// end dbConnection()

/**
 * 执行专门的select操作，注意：在selectSql中的字段和fields中的个数、名称要保持一致
 * @param selectSql 用于执行的select语句
 * @param fields 要选择的字段
 * @return 含有Map的ArrayList，一条记录形成一个Map
 */
public ArrayList dbSelect(String selectSql, ArrayList fields)
{
ArrayList<Map> selectResult = new ArrayList<Map>();
Map<String, String> recordInfo;
try{
selectPro = dbConnection.createStatement();//定义Statement对象
dbResultSet = selectPro.executeQuery(selectSql);
while(dbResultSet.next()){
recordInfo = new HashMap<String, String>();
for(int i = 0; i<fields.size(); ++i)
recordInfo.put((String)fields.get(i), dbResultSet.getString((String)fields.get(i)));
selectResult.add(recordInfo);
}
dbResultSet.close(); //断开结果集
selectPro.close(); //断开Statement对象
}catch(Exception e){
System.out.println("选择操作失败");
System.out.println("Sql = " + selectSql);
e.printStackTrace();
}
return selectResult;
}//end dbSelect(...)

/**
 * 对数据库执行update，delete或insert操作
 * @param sql 要执行操作的sql语句
 * @return 执行成功返回true，失败返回false
 */
public boolean dbUpdate(String sql)
{
try
{
updatePro = dbConnection.createStatement(); //定义Statement对象
updatePro.executeUpdate(sql);
updatePro.close();// -------------关闭Statement对象
return true;
}catch(Exception err){
System.out.println("数据库操作失败！");
System.out.println("Sql = " + sql);
err.printStackTrace();
return false;
}
}//end dbUpdate(...)

/**
 * 关闭数据库连接
 * @return 成功返回true， 失败返回false
 */
public boolean closedatabase()
{
try{
if(dbConnection != null)
dbConnection.close();
return true;
}catch (Exception ex){
ex.printStackTrace();
return false;
}
}//end closeDatabase()