如何在不缓冲输入的情况下从InputStream中读取一行？ [英] How to read a line from InputStream without buffering the input?

问题描述

我有一个InputStream，它包含一个字符串作为字符串，然后是二进制数据。

如果我使用读取新行BufferedReader（new InputStreamReader（inputStream）），二进制数据也被读取，无法重新读取。

如何在不读取的情况下读取一行二进制数据呢？

解决方案

最终手动直接从InputStream读取字节，而不包装InputStream。一切我想，像扫描仪和InputStreamReader的，预读（缓冲区）输入：（

我想我错过了一些情况下，像\r

'pre> 公共静态字符串的readLine（InputStream的的inputStream）抛出IOException异常{
byteArrayOutputStream byteArrayOutputStream =新byteArrayOutputStream（）;
诠释三;
。对于（C = inputStream.read（）;！C = '\\\
' &安培;&安培;！C = -1; C = inputStream.read（））{
byteArrayOutputStream.write（c）中;
}
if（c == -1&& byteArrayOutputStream.size（）== 0）{
return null;
}
String line = byteArrayOutputStream.toString（UTF-8）;
返回行;
}


I have an InputStream which contains a line as a string and then binary data.

If I read the line using new BufferedReader(new InputStreamReader(inputStream)), the binary data is being also read and cannot be re-read.

How can I read a line without reading the binary data as well?

解决方案

Eventually did it manually directly reading byte after byte from the InputStream without wrapping the InputStream. Everything I tried, like Scanner and InputStreamReader, reads ahead (buffers) the input :(

I guess I missed a some cases like \r.

public static String readLine(InputStream inputStream) throws IOException {
    ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
    int c;
    for (c = inputStream.read(); c != '\n' && c != -1 ; c = inputStream.read()) {
        byteArrayOutputStream.write(c);
    }
    if (c == -1 && byteArrayOutputStream.size() == 0) {
        return null;
    }
    String line = byteArrayOutputStream.toString("UTF-8");
    return line;
}

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