项目案例模板之jdbc两种连接方式

第一种连接方式

JDBCUtils.java

 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);

     }

 }

　　

第二种连接方式

db.properties

 url=jdbc:mysql://localhost:3306/aaa?useUnicode=true&characterEncoding=utf-8

 username=root

 password=root

JDBCUtils2.java

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);

     }

 }