写入一个方法，输入一个文件名和一个字符串，统计这个字符串在这个文件中出现的次数。

Posted 2020-10-11 琼biu~~

一

public static int Count(String fileName , String str) throws Exception{
//获取文件中的字符
FileReader fr = new FileReader(new File(fileName));
BufferedReader br = new BufferedReader(fr);
StringBuffer sb = new StringBuffer();
String line;
while((line = br.readLine()) != null ){
sb.append(line);
}
String filestr = sb.toString(); //文件中的字符
System.out.println(filestr);
//统计这个字符串在这个文件中出现的次数

int num = 0;
while(filestr.length() > str.length()){
int index = filestr.indexOf(str);
if(index>-1){ //存在字符串str
num++;
filestr = filestr.substring(index+str.length());
}
else{
break;
}

}
return num;
}

二：

public static int fun(File file,String s){

        int count=0;

        String read;

        String readAll = "";

        int i=0;

        try {

            BufferedReader br = new BufferedReader(new InputStreamReader(new FileInputStream(file)));

            while((read = br.readLine())!=null){

                readAll += read;

            }

            while(readAll.indexOf(s,i)!=-1){

                i=readAll.indexOf(s,i)+s.length();

                count++;

            }

        } catch (FileNotFoundException e) {

            e.printStackTrace();

        } catch (IOException e) {

            e.printStackTrace();

        }

        return count;

    }