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  • JDBC解耦案例

    原始JDBC连接

    package jdbc;
    
            import org.junit.jupiter.api.Test;
    
            import java.sql.Connection;
            import java.sql.DriverManager;
            import java.sql.SQLException;
    
    public class JDBCUtils {
        public static Connection connection;
        private static String url="jdbc:mysql://localhost:3306/aaa?useUnicode=true&characterEncoding=utf-8";
        private static String username="root";
        private static String password="root";
    
        static{
            try {
                Class.forName("com.mysql.jdbc.Driver");
                connection = DriverManager.getConnection(url,username,password);
    
            } catch (ClassNotFoundException e) {
                e.printStackTrace();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    
        public static Connection getConnection(){
            return connection;
        }
    
        @Test
        public void test(){
            Connection connection = JDBCUtils.getConnection();
            System.out.println(connection);
        }
    }
    

      

    解耦JDBC连接

     

    package jdbc;
    
    import org.junit.jupiter.api.Test;
    
    import java.io

    FileInputStream;
    import java.io.FileNotFoundException;
    import java.io.IOException;
    import java.sql.Connection;
    import java.sql.DriverManager;
    import java.sql.SQLException;
    import java.util.Properties;
    
    public class JDBCUtils2 {
        private static Connection connection;
        private static String url;
        private static String username;
        private static String password;
    
        static {
            try {
                //动态加载驱动
                Class.forName("com.mysql.jdbc.Driver");
                //加载配置文件
                Properties properties = new Properties();
                properties.load(new FileInputStream("src/main/java/db.properties"));
                url = properties.getProperty("url");
                username = properties.getProperty("username");
                password = properties.getProperty("password");
    
                connection = DriverManager.getConnection(url,username,password);
    
    
            } catch (ClassNotFoundException e) {
                e.printStackTrace();
            } catch (FileNotFoundException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    
        public static Connection getConnection(){
            return connection;
        }
    
        @Test
        public void test(){
            Connection connection = JDBCUtils2.getConnection();
            System.out.println(connection);
        }
    }
    

      

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  • 原文地址:https://www.cnblogs.com/zyx110/p/11273860.html
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