Java IO开销测试比较

待我称王封你为后i 2022-05-16 14:40 167阅读 0赞

# Java IO开销测试比较 #

2015年02月08日 19:43:27 [飞火流云][Link 1] 阅读数：444更多

个人分类： [Java多线程][Java]

修改了下代码:

1.  `<pre name="code" class="java">package ringBuffer;`
2.   
3.  `import java.io.BufferedWriter;`
4.  `import java.io.FileNotFoundException;`
5.  `import java.io.FileOutputStream;`
6.  `import java.io.FileWriter;`
7.  `import java.io.IOException;`
8.  `import java.io.OutputStreamWriter;`
9.  `import java.io.RandomAccessFile;`
10. `import java.nio.MappedByteBuffer;`
11. `import java.nio.channels.FileChannel;`
12. `import java.nio.channels.FileChannel.MapMode;`
13.  
14. `public class PerformanceWriteTest {`
15. `/**`
16. `* @param args`
17. `*/`
18. `public static void main(String[] args) {`
19.  
20. `String outputFile = "F:\\test\\ioTest.txt";`
21. `Long length = 0L ;`
22. `Long totalTime = 0L;`
23.  
24. `try {`
25. `raf = new RandomAccessFile("F:\\test\\ioTest.txt", "rw");`
26. `FileChannel fc = raf.getChannel();`
27. `mbb = fc.map(MapMode.READ_WRITE, 0, 85*1024*1024);`
28. `} catch (FileNotFoundException e) {`
29. `e.printStackTrace();`
30. `} catch (IOException e) {`
31. `e.printStackTrace();`
32. `}`
33.  
34. `for (int j = 0; j < 5; j++) {`
35. `// for (int j = 0; j < 5; j++) {`
36. `StringBuffer sb = new StringBuffer();`
37. `for (Integer i = 0; i < 1000000; i++) {`
38. `// for (Integer i = 0; i < 100000; i++) {`
39. `sb.append(j+i.toString() + "V");`
40. `}`
41. `sb.append("S");`
42. `// byte[] msgs = sb.toString().getBytes();`
43. `length = (long) sb.toString().length() ;`
44. `long start = System.currentTimeMillis() ;`
45. `appendFileTest(outputFile,sb.toString());`
46. `totalTime = totalTime + (System.currentTimeMillis() - start) ;`
47. `}`
48. `System.out.println(" Total Data is : " + length*5/1000 + " Kbytes! ") ;`
49. `System.out.println(" Total Time is : " + totalTime) ;`
50. `System.out.println(" Averge Speed is :" + length*5/(totalTime*1000) + " Kbytes");`
51. `}`
52.  
53. `private static void appendFileTest(String outputFile, String msgs) {`
54. `// append1(outputFile, msgs) ; //FileOutputStream`
55. `// append2(outputFile, msgs) ; //FileWriter`
56. `// append3(outputFile, msgs) ; //RandomAccessFile`
57. `append4(outputFile, msgs) ; //RandomAccessFile`
58. `}`
59.  
60. `private static void append1(String outputFile, String msgs) {`
61. `BufferedWriter out = null;`
62. `try {`
63. `out = new BufferedWriter(new OutputStreamWriter(`
64. `new FileOutputStream(outputFile, true)));`
65. `out.append(msgs) ;`
66. `} catch (Exception e) {`
67. `e.printStackTrace();`
68. `} finally {`
69. `try {`
70. `out.close();`
71. `} catch (IOException e) {`
72. `e.printStackTrace();`
73. `}`
74. `}`
75. `}`
76.  
77. `private static void append2(String outputFile, String msgs) {`
78. `try {`
79. `FileWriter writer = new FileWriter(outputFile, true); // 打开一个写文件器，构造函数中的第二个参数true表示以追加形式写文件`
80. `writer.write(msgs);`
81. `writer.close();`
82. `} catch (IOException e) {`
83. `e.printStackTrace();`
84. `}`
85. `}`
86.  
87. `private static void append3(String outputFile, String msgs) {`
88. `try {`
89. `RandomAccessFile randomFile = new RandomAccessFile(outputFile, "rw"); // 打开一个随机访问文件流，按读写方式`
90. `long fileLength = randomFile.length(); // 文件长度，字节数`
91. `randomFile.seek(fileLength); // 将写文件指针移到文件尾`
92. `randomFile.writeBytes(msgs);`
93. `randomFile.close();`
94. `} catch (IOException e) {`
95. `e.printStackTrace();`
96. `}`
97. `}`
98.  
99. `private static void append4(String outputFile, String msgs) {`
100. `try {`
101. `mbb.position(pos) ;`
102. `mbb.put(msgs.getBytes());`
103. `pos = pos + msgs.getBytes().length ;`
104. `raf.close();`
105. `} catch (IOException e) {`
106. `e.printStackTrace();`
107. `}`
108. `}`
109.  
110. `static RandomAccessFile raf ;`
111. `static MappedByteBuffer mbb ;`
112. `static Integer pos = 0 ;`
113. `}`

测试时为了增加内存开销，增加了 -XX:+PrintGC 选项，如果大家知道更好的测试内存消耗的方法，请告诉我哈。

1.  `</pre><pre code_snippet_id="600488" snippet_file_name="blog_20150208_4_5933734" name="code" class="java">[GC 32704K->2872K(124992 K), 0.0015308 secs]`
2.  `[GC 35576K->5152K(157696K), 0.0018430 secs]`
3.  `[GC 70560K->9768K(157696K), 0.0032342 secs]`
4.  `[GC 75176K->28240K(223104K), 0.0056030 secs]`
5.  `[GC 159056K->28888K(223104K), 0.0009104 secs]`
6.  `[GC 159704K->37464K(353856K), 0.0033345 secs]`
7.  `[GC 299096K->42152K(354048K), 0.0022436 secs]`
8.  `[GC 303784K->39848K(615 744K), 0.0009303 secs]`
9.  `[GC 563112K->55968K(616 192K), 0.0087540 secs]`
10. ` Total Data is : 39444 Kbytes! `
11. ` Total Time is : 159`
12. ` Averge Speed is :248 Kbytes`
13. `2.826G`
14. ` `
15. `[GC 32704K->2872K(124992K), 0.0136790 secs]`
16. `[GC 35576K->5184K(157696K), 0.0019457 secs]`
17. `[GC 70592K->9792K(157696K), 0.0031822 secs]`
18. `[GC 75200K->28240K(223104K), 0.0056500 secs]`
19. `[GC 152655K->43624K(223104K), 0.0051765 secs]`
20. `[GC 174440K->52848K(353856K), 0.0034980 secs]`
21. `[GC 314480K->55276K(354176K), 0.0013858 secs]`
22. `[GC 314139K->71372K(615488K), 0.0058115 secs]`
23. `[Full GC 71372K->18926K(610816K), 0.0094205 secs]`
24. `[GC 542190K->43678K(610880K), 0.0038294 secs]`
25. ` Total Data is : 39444 Kbytes! `
26. ` Total Time is : 153`
27. ` Averge Speed is :257 Kbytesa`
28. `3.43G`
29. ` `
30. `[GC 32704K->2872K(124992K), 0.0012018 secs]`
31. `[GC 35576K->5184K(124992K), 0.0021390 secs]`
32. `[GC 37888K->9800K(124992K), 0.0031359 secs]`
33. `[GC 42504K->9824K(157696K), 0.0005724 secs]`
34. `[GC 75232K->28208K(157696K), 0.0059463 secs]`
35. `[GC 93616K->28224K(223040K), 0.0007707 secs]`
36. `[GC 159040K->32852K(223360K), 0.0095536 secs]`
37. `[GC 163668K->46740K(354880K), 0.0055367 secs]`
38. `[GC 308372K->55892K(355008K), 0.0032216 secs]`
39. `[GC 317524K->60484K(511168K), 0.0017500 secs]`
40. `[GC 478468K->65092K(511808K), 0.0033206 secs]`
41. ` Total Data is : 39444 Kbytes! `
42. ` Total Time is : 68`
43. ` Averge Speed is :580 Kbytes`
44. `2.87G`

1.  `[GC 32704K->2880K(124992K), 0.0132009 secs]`
2.  `[GC 35584K->5192K(157696K), 0.0017013 secs]`
3.  `[GC 70600K->9800K(157696K), 0.0035649 secs]`
4.  `[GC 75208K->28232K(223104K), 0.0057867 secs]`
5.  `[GC 151138K->43680K(223104K), 0.0055066 secs]`
6.  `[GC 174496K->48256K(353344K), 0.0020662 secs]`
7.  `[GC 298339K->59048K(354496K), 0.0054248 secs]`
8.  `[GC 319528K->77512K(614592K), 0.0058665 secs]`
9.  `[Full GC 77512K->18933K(612224K), 0.0097774 secs]`
10. `[GC 521588K->34405K(612352K), 0.0027320 secs]`
11. ` Total Data is : 39444 Kbytes! `
12. ` Total Time is : 137`
13. ` Averge Speed is :287 Kbytes`
14. `3.4G`

这里很奇怪，理论上Mbb的性能应该远大于这个，可能是我的测试数据量太小的缘故.

综上可见，RandomAccessFile 性价比最高。

[Link 1]: https://me.csdn.net/cloudeagle_bupt
[Java]: https://blog.csdn.net/cloudeagle_bupt/article/category/1415793