JDBC的DBUtils源码

DBUtils源码：

package com.it.util;

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

public class DBUtils {
    private static String driverClass;
    private static String url;
    private static String username;
    private static String password;

    static {
        // 此对象是用于加载properties文件数据的
        ResourceBundle rb = ResourceBundle.getBundle("dbinfo");

        driverClass = rb.getString("driverClass");
        url = rb.getString("url");
        username = rb.getString("username");
        password = rb.getString("password");

        try {
            Class.forName(driverClass);
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
    }

    // 得到连接的方法
    public static Connection getConnection() throws Exception {
        return DriverManager.getConnection(url, username, password);
    }

    // 关闭资源的方法
    public static void closeAll(ResultSet rs, Statement stmt, Connection conn) {
        // 关闭资源
        if (rs != null) {
            try {
                rs.close();
            } catch (Exception e) {
                e.printStackTrace();
            }
            rs = null;
        }
        if (stmt != null) {
            try {
                stmt.close();
            } catch (Exception e) {
                e.printStackTrace();
            }
            stmt = null;
        }
        if (conn != null) {
            try {
                conn.close();
            } catch (Exception e) {
                e.printStackTrace();
            }
            conn = null;
        }
    }
}

dbinfo.properties资源文件：

driverClass=com.mysql.jdbc.Driver
url=jdbc:mysql:///app
username=root
password=root