Java快读写法

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.StringTokenizer;
public class Main {
    static PrintWriter out=new PrintWriter(System.out);
    static FastReader in=new FastReader();
}
class FastReader{
    StringTokenizer st;
    BufferedReader br;
    public FastReader(){
        br=new BufferedReader(new InputStreamReader(System.in));
    }
 
    String next(){
        while (st==null||!st.hasMoreElements()){
            try {
                st=new StringTokenizer(br.readLine());
            }catch (IOException e){
                e.printStackTrace();
            }
        }
        return st.nextToken();
    }
    int nextInt() {return Integer.parseInt(next());
    }
 
    long nextLong() {
        return Long.parseLong(next());
    }
    double nextDouble() {
        return Double.parseDouble(next());
    }
    String nextLine() {
        String str = "";
        try {
            str = br.readLine();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return str;
    }
}