如果您有java.io.InputStream对象,应该如何处理该对象并生成String?


假设我有一个包含文本数据的InputStream,我想将其转换为String,例如,我可以将其写入日志文件。

获取InputStream并将其转换为字符串的最简单方法是什么?

public String convertStreamToString(InputStream is) {
// ???
}

当前回答

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;
}

其他回答

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);
}

如果不能使用Commons IO(FileUtils/IOUtils/CopyUtils),下面是一个使用BufferedReader逐行读取文件的示例:

public class StringFromFile {
    public static void main(String[] args) /*throws UnsupportedEncodingException*/ {
        InputStream is = StringFromFile.class.getResourceAsStream("file.txt");
        BufferedReader br = new BufferedReader(new InputStreamReader(is/*, "UTF-8"*/));
        final int CHARS_PER_PAGE = 5000; //counting spaces
        StringBuilder builder = new StringBuilder(CHARS_PER_PAGE);
        try {
            for(String line=br.readLine(); line!=null; line=br.readLine()) {
                builder.append(line);
                builder.append('\n');
            }
        } 
        catch (IOException ignore) { }

        String text = builder.toString();
        System.out.println(text);
    }
}

或者,如果你想要原始速度,我会根据Paul de Vrieze的建议(避免使用StringWriter(内部使用StringBuffer))提出一个变体:

public class StringFromFileFast {
    public static void main(String[] args) /*throws UnsupportedEncodingException*/ {
        InputStream is = StringFromFileFast.class.getResourceAsStream("file.txt");
        InputStreamReader input = new InputStreamReader(is/*, "UTF-8"*/);
        final int CHARS_PER_PAGE = 5000; //counting spaces
        final char[] buffer = new char[CHARS_PER_PAGE];
        StringBuilder output = new StringBuilder(CHARS_PER_PAGE);
        try {
            for(int read = input.read(buffer, 0, buffer.length);
                    read != -1;
                    read = input.read(buffer, 0, buffer.length)) {
                output.append(buffer, 0, read);
            }
        } catch (IOException ignore) { }

        String text = output.toString();
        System.out.println(text);
    }
}

这是最适合Android和任何其他JVM的纯Java解决方案。

这个解决方案非常好。。。它简单、快速,适用于大小河流!!(见上文第8号基准)

public String readFullyAsString(InputStream inputStream, String encoding)
        throws IOException {
    return readFully(inputStream).toString(encoding);
}

public byte[] readFullyAsBytes(InputStream inputStream)
        throws IOException {
    return readFully(inputStream).toByteArray();
}

private ByteArrayOutputStream readFully(InputStream inputStream)
        throws IOException {
    ByteArrayOutputStream baos = new ByteArrayOutputStream();
    byte[] buffer = new byte[1024];
    int length = 0;
    while ((length = inputStream.read(buffer)) != -1) {
        baos.write(buffer, 0, length);
    }
    return baos;
}

我有log4j可用,所以我可以使用org.apache.log4j.lf5.util.StreamUtils.getBytes来获取字节,我可以使用Stringctor将其转换为字符串

String result = new String(StreamUtils.getBytes(inputStream));

我建议使用StringWriter类来解决这个问题。

StringWriter wt= new StringWriter();
IOUtils.copy(inputStream, wt, encoding);
String st= wt.toString();