JDBCUtils.java

    1. import java.io.FileReader;
    2. import java.io.IOException;
    3. import java.net.URL;
    4. import java.sql.*;
    5. import java.util.Properties;
    7. /**
    8.  * JDBC工具类 8.0jar包版本
    9.  */
    10. public class JDBCUtils {
    11.     private static String url;
    12.     private static String user;
    13.     private static String password;
    15.     /**
    16.      * 文件的读取，只需要读取一次即可拿到这些值。使用静态代码块
    17.      */
    18.     static {
    19.         //读取资源文件，获取值。
    21.         try {
    22.             //1. 创建Properties集合类。
    23.             Properties pro = new Properties();
    25.             //获取src路径下的文件的方式--->ClassLoader 类加载器
    26.             ClassLoader classLoader = JDBCUtils.class.getClassLoader();
    27.             URL res = classLoader.getResource("jdbc.properties");
    28. //            assert res != null;
    29.             String path = res.getPath();
    31.             //2. 加载文件
    32.             pro.load(new FileReader(path));
    34.             //3. 获取数据，赋值
    35.             url = pro.getProperty("url");
    36.             user = pro.getProperty("user");
    37.             password = pro.getProperty("password");
    38.             String driver = pro.getProperty("driver");
    39.             //4. 注册驱动
    40.             Class.forName(driver);
    41.         } catch (IOException e) {
    42.             e.printStackTrace();
    43.         } catch (ClassNotFoundException e) {
    44.             e.printStackTrace();
    45.         }
    46.     }
    49.     /**
    50.      * 获取连接
    51.      *
    52.      * @return 连接对象
    53.      */
    54.     public static Connection getConnection(String dataBaseName) throws SQLException {
    55.         String[] urlElem = url.split("\\?");
    56.         return DriverManager.getConnection(urlElem[0] + dataBaseName + "?" + urlElem[1], user, password);
    57.     }
    59.     /**
    60.      * 释放资源
    61.      *
    62.      * @param stmt
    63.      * @param conn
    64.      */
    65.     public static void close(Statement stmt, Connection conn) {
    66.         if (stmt != null) {
    67.             try {
    68.                 stmt.close();
    69.             } catch (SQLException e) {
    70.                 e.printStackTrace();
    71.             }
    72.         }
    74.         if (conn != null) {
    75.             try {
    76.                 conn.close();
    77.             } catch (SQLException e) {
    78.                 e.printStackTrace();
    79.             }
    80.         }
    81.     }
    84.     /**
    85.      * 释放资源
    86.      *
    87.      * @param stmt
    88.      * @param conn
    89.      */
    90.     public static void close(ResultSet rs, Statement stmt, Connection conn) {
    91.         if (rs != null) {
    92.             try {
    93.                 rs.close();
    94.             } catch (SQLException e) {
    95.                 e.printStackTrace();
    96.             }
    97.         }
    99.         if (stmt != null) {
    100.             try {
    101.                 stmt.close();
    102.             } catch (SQLException e) {
    103.                 e.printStackTrace();
    104.             }
    105.         }
    107.         if (conn != null) {
    108.             try {
    109.                 conn.close();
    110.             } catch (SQLException e) {
    111.                 e.printStackTrace();
    112.             }
    113.         }
    114.     }
    116. }

    jdbc.properties

    1. driver=com.mysql.cj.jdbc.Driver
    2. user=root
    3. password=317499
    4. url=jdbc:mysql://127.0.0.1:3306/?Encoding=utf8&useSSL=false&serverTimezone=UTC&rewriteBatchedStatements=true