前言
正文
就是它
其实我只是偶尔上Stack Overflow,直到看了这个200万次阅读量的提问:
How do I read / convert an InputStream into a String in Java?
我惊呆了!!!
怎么会有这么多人围观。
我第一反应的解决办法是使用Apache commons
包的工具类IOUtils
,果不其然,第一条回答就是这个。
我的天!居然有2000+的赞!
继续往下看,发现大家的不少的骚操作
使用 CharStreams (Guava)
1 | String result = CharStreams.toString(new InputStreamReader( |
使用 Scanner (JDK)
1 | Scanner s = new Scanner(inputStream).useDelimiter("\\A"); |
使用 Stream API (Java 8).
Warning: This solution converts different line breaks (like \r\n) to \n.1
2String result = new BufferedReader(new InputStreamReader(inputStream))
.lines().collect(Collectors.joining("\n"));
使用 parallel Stream API (Java 8).
Warning: This solution converts different line breaks (like \r\n) to \n.1
2String result = new BufferedReader(new InputStreamReader(inputStream)).lines()
.parallel().collect(Collectors.joining("\n"));
使用 InputStreamReader and StringBuilder (JDK)
1 | final int bufferSize = 1024; |
使用 StringWriter and IOUtils.copy (Apache Commons)
1 | StringWriter writer = new StringWriter(); |
使用 ByteArrayOutputStream and inputStream.read (JDK)
1 | ByteArrayOutputStream result = new ByteArrayOutputStream(); |
使用 BufferedReader (JDK).
Warning: This solution converts different line breaks (like \n\r) to line.separator system property (for example, in Windows to “\r\n”).1
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9String newLine = System.getProperty("line.separator");
BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));
StringBuilder result = new StringBuilder();
boolean flag = false;
for (String line; (line = reader.readLine()) != null; ) {
result.append(flag? newLine: "").append(line);
flag = true;
}
return result.toString();
使用 BufferedInputStream and ByteArrayOutputStream (JDK)
1 | BufferedInputStream bis = new BufferedInputStream(inputStream); |
使用 inputStream.read() and StringBuilder (JDK).
Warning: This solution has problems with Unicode, for example with Russian text (works correctly only with non-Unicode text)1
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6int ch;
StringBuilder sb = new StringBuilder();
while((ch = inputStream.read()) != -1)
sb.append((char)ch);
reset();
return sb.toString();
甚至,还贴出了微基准测试的结果,果然狠人啊。
对于小字符串(length = 175) 结果如下:
mode = Average Time, system = Linux, score 1,343 is the best :1
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12 Benchmark Mode Cnt Score Error Units
8. ByteArrayOutputStream and read (JDK) avgt 10 1,343 ± 0,028 us/op
6. InputStreamReader and StringBuilder (JDK) avgt 10 6,980 ± 0,404 us/op
10. BufferedInputStream, ByteArrayOutputStream avgt 10 7,437 ± 0,735 us/op
11. InputStream.read() and StringBuilder (JDK) avgt 10 8,977 ± 0,328 us/op
7. StringWriter and IOUtils.copy (Apache) avgt 10 10,613 ± 0,599 us/op
1. IOUtils.toString (Apache Utils) avgt 10 10,605 ± 0,527 us/op
3. Scanner (JDK) avgt 10 12,083 ± 0,293 us/op
2. CharStreams (guava) avgt 10 12,999 ± 0,514 us/op
4. Stream Api (Java 8) avgt 10 15,811 ± 0,605 us/op
9. BufferedReader (JDK) avgt 10 16,038 ± 0,711 us/op
5. parallel Stream Api (Java 8) avgt 10 21,544 ± 0,583 us/op
对于大字符串(length = 50100) 结果如下:
Performance tests for big String (length = 50100)
mode = Average Time, system = Linux, score 200,715 is the best
1 | Benchmark Mode Cnt Score Error Units |
总结
如获宝藏,看来需要时不时的逛逛Stack Overflow了。
结
转载自:占小狼
以上。