jdbc预编译实现方式

jdbc预编译可以有两种方式：

方式一、jdbc自己实现的预编译，就是做一下特殊字符处理来防SQL注入，看PreparedStatement源码就可以了。

public static void main(String[] args) {

    try {

        final String driverClassName = "com.mysql.jdbc.Driver";
        final String url = "jdbc:mysql://10.6.9.14:3306/SBLOG";  重点看这里
        final String username = "sdl";
        final String password = "sdl";

        Connection connection = DriverManager.getConnection(url2, username, password);

        String sql = " SELECT *\n" +
                "   FROM t_web\n" +
                "  WHERE id = ? and name like ?";

        Class.forName(driverClassName);

        PreparedStatement preparedStatement = connection.prepareStatement(sql);

        preparedStatement.setInt(1, 1);

        preparedStatement.setString(2, "%ing%");

        ResultSet rst = preparedStatement.executeQuery();

        rst.next();

        System.out.println(rst.getString(2));
    } catch (Exception e) {
        e.printStackTrace();
    }

}

这里是调用MySQL时的wireshark截图。可以看下实际上就是拼接完成的SQL发过去的。

方式二、利用MySQL的预编译，。

public static void main(String[] args) {

    try {

        final String driverClassName = "com.mysql.jdbc.Driver";
        final String url2 = "jdbc:mysql://10.6.8.4:3306/SBLOG?useServerPrepStmts=true";  重点看这里增加了useServerPrepStmts=true

        final String username = "sdl";
        final String password = "sdl";

        Connection connection = DriverManager.getConnection(url2, username, password);

        String sql = " SELECT *\n" +
                "   FROM t_web\n" +
                "  WHERE id = ? and name like ?";

        Class.forName(driverClassName);

        PreparedStatement preparedStatement = connection.prepareStatement(sql);

        preparedStatement.setInt(1, 1);

        preparedStatement.setString(2, "%ing%");

        ResultSet rst = preparedStatement.executeQuery();

        rst.next();

        System.out.println(rst.getString(2));
    } catch (Exception e) {
        e.printStackTrace();
    }

}

这里是调用MySQL时的wireshark截图。可以看下实际上参数是用的占位符?。

mybatis这种框架也是一样。关键看你的jdbc url怎么配置的，和框架没关系。