Java快速输入，输出

做算法或多或少会遇到超时，在java中应该是很常见的，下面介绍几种快速输入输出方法
快速输入
1 BufferedReader

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Main{
	public static void main(String[] args) throws IOException {
		BufferedReader in = new BufferedReader(new InputStreamReader(System.in)); // 输入
		// 输入的一行字符
		String line = in.readLine(); 
		System.out.println(line);
	}
}

2. StringTokenizer(个人推荐) 封装好的一个类，直接作为内部类使用

    /** 快速输入类 */
    static class Reader {
        static BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
        static StringTokenizer tokenizer = new StringTokenizer("");
        /** 获取下一段文本 */
        static String next() throws IOException {
            while ( ! tokenizer.hasMoreTokens() ) {
                tokenizer = new StringTokenizer(reader.readLine());
            }
            return tokenizer.nextToken();
        }
        static int nextInt() throws IOException {
            return Integer.parseInt( next() );
        }
        static double nextDouble() throws IOException {
            return Double.parseDouble( next() );
        }
    }

3.StreamTokenizer
这个限制就比较多，只能严格接收字母或者数字，其他特殊字符接收都是null
但是有一点很疑惑，StreamTokenizer 似乎比BufferedReader 更快一点
PAT上的题BufferedReader 过不了，但是 StreamTokenizer 能过
看大家取舍

static BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
    static StreamTokenizer in = new StreamTokenizer(reader);
    
    public static void main(String[] args) throws IOException {
		int n = nextInt();
		String a = next();
    }
    static String next() throws IOException {
        in.nextToken();
        return in.sval;
    }
    /** 获取数字 */
    static int nextInt() throws IOException {
        in.nextToken();
        return (int)in.nval;
    }
    static double nextDouble() throws IOException {
        in.nextToken();
        return in.nval;
    }

快速输出
PrintWriter

PrintWriter out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(System.out)));
out.print(text);
out.flush(); //刷新缓存区