import java.io.BufferedInputStream;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Properties;

import com.mysql.jdbc.ResultSetMetaData;

/**
 * 
 * @author dgm
 * @describe "原生jdbc"
 * @date 2020年4月13日
 */
public class MysqlTest {
    // JDBC 驱动名及数据库 URL
    static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";
    static final String DB_URL = "jdbc:mysql://192.168.8.200:3306/bdrackdemo?useUnicode=true&characterEncoding=utf8&autoReconnect=true";
    // 数据库的用户名与密码，需要根据自己的设置
    static final String USER = "root";
    static final String PASS = "cstorfs";
    static Properties prop = new Properties();

    //读取数据库配置文件
    static void readDBSetting(String path) {
        // Properties prop = new Properties();
        // 读取属性文件mysql.properties
        InputStream in = null;
        try {
            in = new BufferedInputStream(new FileInputStream(path));
        } catch (FileNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        try {
            prop.load(in);
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } // /加载属性列表
        Iterator<String> it = prop.stringPropertyNames().iterator();
        while (it.hasNext()) {
            String key = it.next();
            System.out.println(key + "=" + prop.getProperty(key));
        }
        try {
            in.close();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        // return prop;
    }

    public static void main(String[] args) {
        // 读取mysql 配置信息
        readDBSetting("conf/mysql.properties");

        Connection conn = null;
        Statement stmt = null;
        ResultSet rs = null;
        try {
            // 注册 JDBC 驱动
            Class.forName(prop.getProperty("dbDriver")).newInstance();

            // 打开链接
            System.out.println("连接数据库...");
            conn = DriverManager
                    .getConnection(
                            "jdbc:mysql://"
                                    + prop.getProperty("mysqlhost")
                                    + ":"
                                    + prop.getProperty("mysqlport")
                                    + "/"
                                    + prop.getProperty("dbname")
                                    + "?useUnicode=true&characterEncoding=utf8&autoReconnect=true",
                            prop.getProperty("mysqluser"),
                            prop.getProperty("mysqlpwd"));

            // 执行查询
            System.out.println(" 实例化Statement对象...");
            stmt = conn.createStatement();
            String sql = "SELECT id, username, number FROM student";
            rs = stmt.executeQuery(sql);

            // 展开结果集数据库
            while (rs.next()) {
                // 输出数据
                System.out.print("用户id: " + rs.getInt("id"));
                System.out.print(", 用户名: " + rs.getString("username"));
                System.out.print(", 学号: " + rs.getString("number"));
                System.out.print("\n");
            }
        } catch (SQLException se) {
            // 处理 JDBC 错误
            se.printStackTrace();
        } catch (Exception e) {
            // 处理 Class.forName 错误
            e.printStackTrace();
        } finally {
            // 关闭资源
            try {
                if (rs != null)
                    rs.close();
            } catch (SQLException se3) {
            }// 什么都不做
            // 关闭资源
            try {
                if (stmt != null)
                    stmt.close();
            } catch (SQLException se2) {
            }// 什么都不做
            try {
                if (conn != null)
                    conn.close();
            } catch (SQLException se) {
                se.printStackTrace();
            }
        }
    }
}