快读

import java.io.*;
public class test {public static void main(String args[]) throws IOException{StreamTokenizer st = new StreamTokenizer(new BufferedReader(new InputStreamReader(System.in))); st.nextToken();String str = st.sval;//读取String类型数据st.nextToken();double num1 =  st.nval;//读取double类型数据st.nextToken();int num2 = (int)st.nval;//读取int类型数据st.nextToken();long num3 = (long)st.nval;//读取long类型数据// 读取字符串，不用每次st.nextToken()BufferedReader re = new BufferedReader(new InputStreamReader(System.in));String x = re.readLine();System.out.println(x);}
}

每读一个数据就要用一次 nextToken（）

快写

PrintWriter out = new PrintWriter(new OutputStreamWriter(System.out));
out.write("hello world!")
int a = 1;
out.write(a.toString()); // 如果输出int型，要转为String
out.flush(); // 将输出缓冲区清空(最后如果没有这句代码，就会什么也不输出)