Question

我想知道在按下按钮（键绑定）完成后，我可以关闭数据库连接。

这是我得到的：

public static void main(String[] argv) {

        System.out.println("-------- MySQL JDBC Connection Testing ------------");

        try {
            Class.forName("com.mysql.jdbc.Driver");
        } catch (ClassNotFoundException e) {
            System.out.println("Where is your MySQL JDBC Driver?");
            e.printStackTrace();
            return;
        }

        System.out.println("MySQL JDBC Driver Registered!");
        Connection connection = null;

        try {
            connection = DriverManager.getConnection("jdbc:mysql://localhost:3306/db_test14", "root", "password");


        } catch (SQLException e) {
            System.out.println("Connection Failed! Check output console");
            e.printStackTrace();
            return;
        }

        if (connection != null) {
            System.out.println("Connection to DB Success!");
        } else {
            System.out.println("Failed to make connection!");
        }
        System.out.println("\n" + "----------- Database Results ------------" + "\n");

        try {

            Statement stmt = connection.createStatement();
            String sql = "SELECT * FROM first_table";
            ResultSet rs = stmt.executeQuery(sql);

            while (rs.next()) {
                int id_col = rs.getInt("id");
                String name = rs.getString("name");
                String address = rs.getString("address");



                String p = id_col + " " + name + " " + address;
                System.out.println(p);
            }
        } catch (SQLException e) {
             e.printStackTrace();
        }


    }
}

我是否必须在查询语句后添加close连接？

希望得到一些帮助。

Answer 1

实际上这取决于您的业务，如果您刚刚完成使用数据库，然后关闭连接，如果不是，请保持连接打开，但关闭Statement和ResultSet反对

对于第二个选项，您可能需要创建一个负责连接的类，并在每次要使用DB时使用它。检查this寻求帮助。

Answer 2

我在这做什么

  call resultset.close  just after finishing your execution.
  rs.close();

   finally
      {
          try
          {
              if(stmt!=null)
                  stmt.close();
          }
          catch (Throwable th)
          {}
          catch (Throwable th)
          {}
          try
          {
              if (connection != null)
                  connection.close();
          }
          catch (Throwable th)
          {}
      }
  }

如何使用按钮关闭数据库连接

2 个答案: