技术与生活 性能之重 FileOutputStream、BufferedOutputStream、FileWriter、BufferedWriter、GetBytes性能

FileOutputStream、BufferedOutputStream、FileWriter、BufferedWriter、GetBytes性能

作者: charlie_chen 发布: 2021年1月3日 4431阅读

测试FileOutputStream、BufferedOutputStream、FileWriter、BufferedWriter、GetBytes的性能。

直接上结论：

  1. BufferedOutputStream直接写byte[]最快；比BufferedWriter快一倍；
  2. FileOutputStream最慢，差数量级；
  3. 从快到慢顺序：BufferedOutputStream直接写byte[]>BufferedWriter>FileWrite>BufferedOutputStream>FileOutputStream直接写byte[]>FileOutputStream;
  4. GetBytes相当耗时，在有Buffer的流时，比写入文件还耗时。
  • 本次测试环境：笔记本 HP ZBOOK 15
  • 本次测试共写入100万行，写入到SSD盘
  • 每行内容：ABCDEFGHIJKLMNOPQRSTUVWXYZ abcdefghijklmnopqrstuvwxyz 0123456789

程序输出记录如下：

Test Performance Version 0.2
DESC:Test FileOutputStream、BufferedOutputStream、FileWriter、BufferedWriter、GetBytes.
Author: Charlie Chen
Date: 2021.01.03

------------------------ Info --------------------
Line content：ABCDEFGHIJKLMNOPQRSTUVWXYZ abcdefghijklmnopqrstuvwxyz 0123456789
Lint count： 1000000
------------------------ Info --------------------

------------------------ Begin --------------------
FileOutputStream Elapse:                3388 ms
FileOutputStreamBytes Elapse:           2944 ms
BufferedOutputStream Elapse:            298 ms
BufferedOutputStreamBytes Elapse:       101 ms
FileWriter Elapse:                      279 ms
BufferedWriter Elapse:                  213 ms

GetBytes Elapse:                        187 ms
------------------------ End --------------------

程序源码如下：


import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.FileWriter;
import java.io.BufferedWriter;

//测试FileOutputStream、BufferedOutputStream、FileWriter、BufferedWriter、GetBytes的性能
public class Test {

	// 写文件行数
	private static int count = 1000000;

	// 写文件每行的内容
	private static String content = "ABCDEFGHIJKLMNOPQRSTUVWXYZ abcdefghijklmnopqrstuvwxyz 0123456789\r\n";
	// 写文件每行的内容，byte数组格式
	private static byte[] contentBytes = content.getBytes();

	//主程序
	public static void main(String[] args) throws Exception {
		System.out.println("Test Performance Version 0.2");
		System.out.println("DESC:Test FileOutputStream、BufferedOutputStream、FileWriter、BufferedWriter、GetBytes.");
		System.out.println("Author: Charlie Chen");
		System.out.println("Date: 2021.01.03");
		System.out.println("");
		System.out.println("------------------------ Info --------------------");
		System.out.println("Line content："+content.substring(0,content.length()-2));
		System.out.println("Lint count： " + count);
		System.out.println("------------------------ Info --------------------");
		System.out.println("");
		System.out.println("------------------------ Begin --------------------");
		
		testFileOutputStream();
		testFileOutputStreamBytes();
		testBufferedOutputStream();
		testBufferedOutputStreamBytes();
		testFileWriter();
		testBufferedWriter();
		testGetBytes();
		
		System.out.println("------------------------ End --------------------");
	}

	// 测试FileOutputStream的性能，并输出
	private static void testFileOutputStream() throws Exception {
		// 测试FileOutputStream
		FileOutputStream os = null;
		try {
			// 打开文件
			os = new FileOutputStream(new File("C:\\temp\\FileOutputStream.txt"));
			long begin = System.currentTimeMillis();
			// 写入数据
			for (int i = 0; i < count; i++) {
				os.write(content.getBytes());
			}
			os.flush();
			os.close();
			long end = System.currentTimeMillis();
			// 打印输出
			System.out.println(formatStr("FileOutputStream Elapse:") + (end - begin) + " ms");
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			os.close();
		}
	}

	// 测试FileOutputStream的性能(直接写byte数组)，并输出
	private static void testFileOutputStreamBytes() throws Exception {
		// 测试FileOutputStream
		FileOutputStream os = null;
		try {
			// 打开文件
			os = new FileOutputStream(new File("C:\\temp\\FileOutputStreamBytes.txt"));
			long begin = System.currentTimeMillis();
			// 写入数据
			for (int i = 0; i < count; i++) {
				os.write(contentBytes);
			}
			os.flush();
			os.close();
			long end = System.currentTimeMillis();
			// 打印输出
			System.out.println(formatStr("FileOutputStreamBytes Elapse:") + (end - begin) + " ms");
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			os.close();
		}
	}

	// 测试BufferedOutputStream的性能，并输出
	private static void testBufferedOutputStream() throws Exception {
		// 测试BufferedOutputStream
		FileOutputStream fos = null;
		BufferedOutputStream bos = null;

		try {
			// 打开文件
			fos = new FileOutputStream(new File("C:\\temp\\BufferedOutputStream.txt"));
			bos = new BufferedOutputStream(fos);
			long begin = System.currentTimeMillis();
			// 写入数据
			for (int i = 0; i < count; i++) {
				bos.write(content.getBytes());
			}
			bos.flush();
			bos.close();
			long end = System.currentTimeMillis();
			// 打印输出
			System.out.println(formatStr("BufferedOutputStream Elapse:") + (end - begin) + " ms");
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			bos.close();
		}
	}

	// 测试BufferedOutputStream的性能(直接写byte数组)，并输出
	private static void testBufferedOutputStreamBytes() throws Exception {
		// 测试BufferedOutputStream
		FileOutputStream fos = null;
		BufferedOutputStream bos = null;

		try {
			// 打开文件
			fos = new FileOutputStream(new File("C:\\temp\\BufferedOutputStreamBytes.txt"));
			bos = new BufferedOutputStream(fos);
			long begin = System.currentTimeMillis();
			// 写入数据
			for (int i = 0; i < count; i++) {
				bos.write(contentBytes);
			}
			bos.flush();
			bos.close();
			long end = System.currentTimeMillis();
			// 打印输出
			System.out.println(formatStr("BufferedOutputStreamBytes Elapse:") + (end - begin) + " ms");
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			bos.close();
		}
	}

	// 测试FileWriter的性能，并输出
	private static void testFileWriter() throws Exception {
		// 测试FileWriter
		FileWriter fw = null;
		try {
			// 打开文件
			fw = new FileWriter("C:\\temp\\FileWriter.txt");
			long begin = System.currentTimeMillis();
			// 写入数据
			for (int i = 0; i < count; i++) {
				fw.write(content);
			}
			fw.flush();
			fw.close();
			long end = System.currentTimeMillis();
			// 打印输出
			System.out.println(formatStr("FileWriter Elapse:") + (end - begin) + " ms");
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			fw.close();
		}
	}

	// 测试BufferedWriter的性能，并输出
	private static void testBufferedWriter() throws Exception {
		// 测试BufferedWriter
		FileWriter fw = null;
		BufferedWriter bfw = null;
		try {
			// 打开文件
			fw = new FileWriter("C:\\temp\\BufferedWriter.txt");
			bfw = new BufferedWriter(fw);
			long begin = System.currentTimeMillis();
			// 写入数据
			for (int i = 0; i < count; i++) {
				bfw.write(content);
			}
			bfw.flush();
			bfw.close();
			long end = System.currentTimeMillis();
			// 打印输出
			System.out.println(formatStr("BufferedWriter Elapse:") + (end - begin) + " ms");
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			bfw.close();
		}
	}

	// 测试GetBytes的性能，并输出
	private static void testGetBytes() throws Exception {
		try {		
			long begin = System.currentTimeMillis();
			// 写入数据
			for (int i = 0; i < count; i++) {
				content.getBytes();
			}
			long end = System.currentTimeMillis();
			// 打印输出
			System.out.println("");
			System.out.println( formatStr("GetBytes Elapse:") + (end - begin) + " ms");
		} catch (Exception e) {
			e.printStackTrace();
		} 
	}
	// 把字符串变成长度40，不足补空格
	private static String formatStr(String s) {
		int len=40;
		String rs="";
		for(int i=0;i<len;i++) {
			if(i<s.length()) {
				rs+=s.charAt(i);
			}
			else {
				rs+=" ";
			}				
		}		
		return rs;
	}
}
本文来自网络，不代表【技术与生活】立场，转载请注明出处。http://4i-bird.com/2021/01/03/fileoutputstream%e3%80%81bufferedoutputstream%e3%80%81filewriter%e3%80%81bufferedwriter%e3%80%81getbytes%e6%80%a7%e8%83%bd/
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作者: charlie_chen

编程是一生最爱： >> 架构与设计； >> 软件工程； >> 项目管理； >> 产品研发。

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