此代码段位于\sdk\samples\android-19\connection\NetworkConnect\NetworkConnectSample\src\main\java.com\example\android\NetworkConnect\MainActivity.java中，该代码段根据Apache许可证2.0版授权，由Google编写。

/** Reads an InputStream and converts it to a String.
 * @param stream InputStream containing HTML from targeted site.
 * @param len Length of string that this method returns.
 * @return String concatenated according to len parameter.
 * @throws java.io.IOException
 * @throws java.io.UnsupportedEncodingException
 */
private String readIt(InputStream stream, int len) throws IOException, UnsupportedEncodingException {
    Reader reader = null;
    reader = new InputStreamReader(stream, "UTF-8");
    char[] buffer = new char[len];
    reader.read(buffer);
    return new String(buffer);
}

与Okio一起：

String result = Okio.buffer(Okio.source(inputStream)).readUtf8();

此外，您还可以从指定的资源路径获取InputStream：

public static InputStream getResourceAsStream(String path)
{
    InputStream myiInputStream = ClassName.class.getResourceAsStream(path);
    if (null == myiInputStream)
    {
        mylogger.info("Can't find path = ", path);
    }

    return myiInputStream;
}

要从特定路径获取InputStream，请执行以下操作：

public static URL getResource(String path)
{
    URL myURL = ClassName.class.getResource(path);
    if (null == myURL)
    {
        mylogger.info("Can't find resource path = ", path);
    }
    return myURL;
}

这个很好，因为：

它可以安全地处理Charset。您可以控制读取缓冲区的大小。您可以设置生成器的长度，而不必是精确的值。不受库依赖关系的影响。适用于Java 7或更高版本。

怎么做？

public static String convertStreamToString(InputStream is) throws IOException {
   StringBuilder sb = new StringBuilder(2048); // Define a size if you have an idea of it.
   char[] read = new char[128]; // Your buffer size.
   try (InputStreamReader ir = new InputStreamReader(is, StandardCharsets.UTF_8)) {
     for (int i; -1 != (i = ir.read(read)); sb.append(read, 0, i));
   }
   return sb.toString();
}

对于JDK 9

public static String inputStreamString(InputStream inputStream) throws IOException {
    try (inputStream) {
        return new String(inputStream.readAllBytes(), StandardCharsets.UTF_8);
    }
}

如果你喜欢冒险，你可以把Scala和Java混合起来，最后得到这样的结果：

scala.io.Source.fromInputStream(is).mkString("")

混合Java和Scala代码和库有其好处。

请参阅此处的完整描述：在Scala中将InputStream转换为String的惯用方法

Use:

InputStream in = /* Your InputStream */;
StringBuilder sb = new StringBuilder();
BufferedReader br = new BufferedReader(new InputStreamReader(in));
String read;

while ((read=br.readLine()) != null) {
    //System.out.println(read);
    sb.append(read);
}

br.close();
return sb.toString();