怎样应对黑客暴力破解密码?

线上的一个应用,没对外宣传,但似乎有黑客在探测密码了. docker 启动的 mysql,看控制台标准输出,一直在这样,是在暴力破解密码吗?:

2017-11-21T06:09:41.804288Z 122 [Note] Access denied for user 'root'@'121.207.227.164' (using password: YES)

database_1 | 2017-11-21T06:09:43.610338Z 123 [Note] Access denied for user 'root'@'121.207.227.164' (using password: YES)

我已经加过过滤器了,如下:

import javax.servlet.*; import javax.servlet.annotation.WebFilter; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import java.io.IOException; import java.util.Enumeration;

/** * / @WebFilter(filterName="sqlAttackFilter",urlPatterns="/") public class SqlAttackFilter implements Filter { @Override public void destroy() { }

@Override
public void doFilter(ServletRequest request, ServletResponse response,
                     FilterChain chain) throws IOException, ServletException {
    HttpServletRequest req=(HttpServletRequest)request;
    HttpServletResponse res=(HttpServletResponse)response;
    //获得所有请求参数名
    Enumeration params = req.getParameterNames();
    String sql = "";
    while (params.hasMoreElements()) {
        //得到参数名
        String name = params.nextElement().toString();
        //System.out.println("name===========================" + name + "--");
        //得到参数对应值
        String[] value = req.getParameterValues(name);
        for (int i = 0; i < value.length; i++) {
            sql = sql + value[i];
        }
    }
    //有 sql 关键字，跳转到 error.html
    if (sqlValidate(sql)) {
        throw new IOException("--------------------->never put in illegal code");
        //String ip = req.getRemoteAddr();
    } else {
        chain.doFilter(request,response);
    }
}

//效验
protected static boolean sqlValidate(String str) {
    str = str.toLowerCase();//统一转为小写
    String badStr = "'|and|exec|execute|insert|select|delete|update|count|drop|*|%|chr|mid|master|truncate|" +
            "char|declare|sitename|net user|xp_cmdshell|;|or|-|+|,|like'|and|exec|execute|insert|create|drop|" +
            "table|from|grant|use|group_concat|column_name|" +
            "information_schema.columns|table_schema|union|where|select|delete|update|order|by|count|*|" +
            "chr|mid|master|truncate|char|declare|or|;|-|--|+|,|like|//|/|%|#";//过滤掉的 sql 关键字，可以手动添加
    String[] badStrs = badStr.split("\\|");
    for (int i = 0; i < badStrs.length; i++) {
        if (str.indexOf(badStrs[i]) >= 0) {
            return true;
        }
    }
    return false;
}

@Override
public void init(FilterConfig config) throws ServletException {
}

}

我想知道他是在用什么方式搞的,有什么应对办法?