将新字符串添加到hashmap java

我正在编写一个程序来读取日志文件,然后计算某些字符串的显示次数.我试图手动输入字符串作为关键字,但由于有这么多,我认为搜索日志文件会更好,当遇到“ua”时,它应该创建一个从“ua”到该行的结尾,将其添加到hashmap,并增加该特定字符串的计数(我感兴趣的所有字符串都以“ua”开头).我似乎无法弄清楚如何将新字符串添加到hashmap中.这就是我到目前为止所拥有的.

public class Logs
{

public static void main(String args[]) throws IOException 
{

 Map<String,Integer> dayCount = new HashMap<String,Integer>();
    for (String str : KeyWords)
    {
        dayCount.put(str,0);
    }

    File path = new File("C:P4logs"); 
    for(File f: path.listFiles())
    { // this loops through all the files + directories

        if(f.isFile()) 
        { // checks if it is a file,not a directory.

    try (BufferedReader br = new BufferedReader(new FileReader(f.getAbsolutePath())))
    {


String sCurrentLine;

while ((sCurrentLine = br.readLine()) != null) 
{
    boolean found = false;

    for (String str : DayCount.keySet()) 
    {
        if (sCurrentLine.indexOf(str) != -1)
        {
            DayCount.put(str,DayCount.get(str) + 1);
            found = true;
            break;
        }
     }
     if (!found && sCurrentLine.indexOf("ua,") != -1)
     {
        System.out.println("Found an unknown user action: " + sCurrentLine);
        DayCount.put(key,value)    //not sure what to put here
     }
    }
   }
 for(String str : KeyWords)
    {
         System.out.println(str + " = " + DayCount.get(str));

    }

    }
   }
}

}

//If a key doesn't exist in a hashmap,`get(T)` returns null
if(DayCount.get(str) == null) {
    //We know this key doesn't exist,so let's create a new entry with 1 as the count
    DayCount.put(str,1);
} else {
    //We know this key exists,so let's get the old count,increment it,and then update
    //the value
    int count = DayCount.get(str);
    DayCount.put(str,count + 1);
}