java--连接数据库的工具类以及关闭连接

import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;
/**
 * jdbc的工具类
  用这个类的时候前提是  首先要有一个db.properties  文件  在src目录下可以直接创建
 * @author Administrator
 *
 */
public class JDBCUtils {
	


	static Properties properties=null;
	
	static{
		properties=new Properties();
		try {
			properties.load(Thread.currentThread().getContextClassLoader().getResourceAsStream("db.properties"));
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		
	}
	/*
	 * 返回数据库的连接
	 */
	public static  Connection getConnection(){
		try {
			Class.forName(properties.getProperty("mysqlDriver"));
			return DriverManager.getConnection(properties.getProperty("mysqlUrl"), properties.getProperty("mysqlUser"),
					properties.getProperty("mysqlPassword"));
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
			return null;
		}
	}
	
	public static void close(Connection con){
		if(con!=null){
			try {
				con.close();
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
	}
	
	public static void close(Connection con,PreparedStatement ps,ResultSet rs) {
		if(con!=null){
			try {
				con.close();
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
		if(ps!=null){
			try {
				ps.close();
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
		if(rs!=null){
			try {
				rs.close();
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
	}
	public static void close(Connection con,PreparedStatement ps){
		if(con!=null){
			try {
				con.close();
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
		if(ps!=null){
			try {
				ps.close();
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
	}
	
	public static void close(Connection con,Statement stst){
		if(con!=null){
			try {
				con.close();
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
		if(stst!=null){
			try {
				stst.close();
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
	}
}