重载

静态方法 关闭时可以重载。同样的结构/方法名。用入参区分。

package com.cdw.bbs;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class DB {

public static Connection getConn() {

	Connection conn = null;

	try {
		Class.forName("com.mysql.jdbc.driver");

		conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/bbs", "root", "huawei@1234");
	} catch (ClassNotFoundException e) {
		// TODO Auto-generated catch block
		e.printStackTrace();
	} catch (SQLException e) {
		// TODO Auto-generated catch block
		e.printStackTrace();
	}

	return conn;

}

public static Statement getStmt(Connection conn) {
	Statement stmt = null;

	try {
		stmt = conn.createStatement();
	} catch (SQLException e) {
		// TODO Auto-generated catch block
		e.printStackTrace();
	}

	return stmt;
}

public static ResultSet executeQuery(Statement stmt, String sql) {
	ResultSet rs = null;
	try {
		rs = stmt.executeQuery(sql);
	} catch (SQLException e) {
		// TODO Auto-generated catch block
		e.printStackTrace();
	}

	return rs;

}

public static void close(Connection conn) {

	if (conn != null) {

		try {
			conn.close();
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}

	}
	conn = null;

}

public static void close(Statement stmt) {

	if (stmt != null) {

		try {
			stmt.close();
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}

	}
	stmt = null;

}

public static void close(ResultSet rs) {

	if (rs != null) {

		try {
			rs.close();
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}

	}
	rs = null;

}

}