小编典典

将InputStream转换为字符串的方法：

使用IOUtils.toString(Apache Utils)

String result = IOUtils.toString(inputStream, StandardCharsets.UTF_8);

使用CharStreams(Guava)

String result = CharStreams.toString(new InputStreamReader(

inputStream, Charsets.UTF_8));

使用Scanner(JDK)

Scanner s = new Scanner(inputStream).useDelimiter("\\A");

String result = s.hasNext() ? s.next() : "";

使用Stream API(Java 8)。警告：此解决方案会将不同的换行符(如\r\n)转换为\n。

String result = new BufferedReader(new InputStreamReader(inputStream))

.lines().collect(Collectors.joining("\n"));

使用并行流API(Java 8)。警告：此解决方案会将不同的换行符(如\r\n)转换为\n。

String result = new BufferedReader(new InputStreamReader(inputStream)).lines()

.parallel().collect(Collectors.joining("\n"));

使用InputStreamReader和StringBuilder(JDK)

final int bufferSize = 1024;

final char[] buffer = new char[bufferSize];

final StringBuilder out = new StringBuilder();

Reader in = new InputStreamReader(stream, StandardCharsets.UTF_8);

int charsRead;

while((charsRead = in.read(buffer, 0, buffer.length)) > 0) {

out.append(buffer, 0, charsRead);

}

return out.toString();

使用StringWriter和IOUtils.copy(Apache Commons)

StringWriter writer = new StringWriter();

IOUtils.copy(inputStream, writer, "UTF-8");

return writer.toString();

使用ByteArrayOutputStream和inputStream.read(JDK)

ByteArrayOutputStream result = new ByteArrayOutputStream();

byte[] buffer = new byte[1024];

int length;

while ((length = inputStream.read(buffer)) != -1) {

result.write(buffer, 0, length);

}

// StandardCharsets.UTF_8.name() > JDK 7

return result.toString("UTF-8");

使用BufferedReader(JDK)。警告：此解决方案将不同的换行符(如\n\r)转换为line.separator系统属性(例如，在Windows中转换为“ \ r \ n”)。

String 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和ByteArrayOutputStream(JDK)

BufferedInputStream bis = new BufferedInputStream(inputStream);

ByteArrayOutputStream buf = new ByteArrayOutputStream();

int result = bis.read();

while(result != -1) {

buf.write((byte) result);

result = bis.read();

}

// StandardCharsets.UTF_8.name() > JDK 7

return buf.toString("UTF-8");

使用inputStream.read()和StringBuilder(JDK)。警告：此解决方案存在Unicode问题，例如俄语文本(仅适用于非Unicode文本)

int ch;

StringBuilder sb = new StringBuilder();

while((ch = inputStream.read()) != -1)

sb.append((char)ch);

reset();

return sb.toString();

2020-01-10