简单的JDBC封装

JDBC（Java Data Base Connectivity,java数据库连接）是一种用于执行SQL语句的Java API，可以为多种关系数据库提供统一访问，它由一组用Java语言编写的类和接口组成。

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 {
			//MySQL
			Class.forName("com.mysql.jdbc.Driver");
			conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/xxx", "root","123456");
		} catch (ClassNotFoundException e) {
			e.printStackTrace();
		} catch (SQLException e) {
			e.printStackTrace();
		}
		return conn;
	}

	public static Statement getStmt(Connection conn) {
		Statement stmt = null;
		try {
			stmt = conn.createStatement();
		} catch (SQLException e) {
			e.printStackTrace();
		}
		return stmt;
	}

	public static ResultSet executeQuery(Statement stmt,String sql) {
		ResultSet rs = null;
		try {
			rs = stmt.executeQuery(sql);
		} catch (SQLException e) {
			e.printStackTrace();
		}
		return rs;
	}

	public static void close(Connection conn) {
		if(conn != null) {
			try {
				conn.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}
			conn = null;
		}
	}

	public static void close(Statement stmt) {
		if(stmt != null) {
			try {
				stmt.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}
			stmt = null;
		}
	}

	public static void close(ResultSet rs) {
		if(rs != null) {
			try {
				rs.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}
			rs = null;
		}
	}
}