将字符串输出到系统的最快方法是什么？ [英] What's the fastest way to output a string to system out?

问题描述

我正在做这样的事情：

for (int i = 0; i < 100000; i++) {
   System.out.println( i );
}

基本上，我计算一个整数并输出大约10K-100K次的字符串然后需要将结果写入system.out，每个结果用换行符分隔。

Basically, I compute an integer and output a string about 10K-100K times and then need to write the result to system.out, each result separated by a newline.

实现此目的的最快方法是什么？

What's the fastest way to achieve this?

推荐答案

感谢您的建议。我创建了一个测试程序来比较它们：

Thank you for the suggestions. I created a test program to compare them:

import java.io.BufferedOutputStream;
import java.io.BufferedWriter;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.lang.StringBuilder;

public class systemouttest {

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

        long starttime = System.currentTimeMillis();
        for (int i = 0; i < 100000; i++) {
           System.out.println( i );
        }
        long printlntime = System.currentTimeMillis();

        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < 100000; i++) {
            sb.append( i + "\n" );
        }
        System.out.print(sb.toString());
        long stringbuildertime = System.currentTimeMillis();

        OutputStream out = new BufferedOutputStream ( System.out );
        for (int i = 0; i < 100000; i++) {
            out.write((i + "\n").getBytes());
        }
        out.flush();
        long bufferedoutputtime = System.currentTimeMillis();

        BufferedWriter log = new BufferedWriter(new OutputStreamWriter(System.out));
        for (int i = 0; i < 100000; i++) {
            log.write(i + "\n");
        }
        log.flush();
        long bufferedwritertime = System.currentTimeMillis();

        System.out.println( "System.out.println: " + (printlntime - starttime) );
        System.out.println( "StringBuilder: " + (stringbuildertime - printlntime) );
        System.out.println( "BufferedoutputStream: " + (bufferedoutputtime - stringbuildertime) );
        System.out.println( "BufferedWriter: " + (bufferedwritertime - bufferedoutputtime) );
    }

}

结果：



Environment1

System.out.println：482

StringBuilder：210

BufferedoutputStream：86

BufferedWriter：202



Environment2

System.out.println：1763

StringBuilder：45

BufferedoutputStream：76

BufferedWriter：34

Results:

Environment1
System.out.println: 482
StringBuilder: 210
BufferedoutputStream: 86
BufferedWriter: 202

Environment2
System.out.println: 1763
StringBuilder: 45
BufferedoutputStream: 76
BufferedWriter: 34

所有建议都比System.out.println更好。 BufferedOutputStream似乎是最安全的选择，因为它在两个测试环境中都表现良好。 BufferedWriter可能会更快。

The suggestions all performed better than System.out.println. BufferedOutputStream seems to be the safest choice as it performed well in both test environments. BufferedWriter maybe faster though.

如果有人有想法，请发布更多建议。我相信有人可以让它变得更快：）

Please post further suggestions if anyone has some ideas. I'm sure someone can make it go faster :)

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