我编写了一个小型命令行程序来读取网页并将响应正文打印到终端。
这适用于大多数网站,但是当从该网址读取分块响应时:http: //www.pampers.co.uk/home我得到以下回溯:
java.io.IOException: Premature EOF
at sun.net.www.http.ChunkedInputStream.readAheadBlocking(ChunkedInputStream.java:538)
at sun.net.www.http.ChunkedInputStream.readAhead(ChunkedInputStream.java:582)
at sun.net.www.http.ChunkedInputStream.read(ChunkedInputStream.java:669)
at java.io.FilterInputStream.read(FilterInputStream.java:116)
at sun.net.www.protocol.http.HttpURLConnection$HttpInputStream.read(HttpURLConnection.java:2668)
at sun.nio.cs.StreamDecoder.readBytes(StreamDecoder.java:264)
at sun.nio.cs.StreamDecoder.implRead(StreamDecoder.java:306)
at sun.nio.cs.StreamDecoder.read(StreamDecoder.java:158)
at java.io.InputStreamReader.read(InputStreamReader.java:167)
at java.io.Reader.read(Reader.java:123)
at HttpPageReader.main(HttpPageReader.java:44)`
我已经对字符集进行了硬编码以匹配此页面的响应。我应该采取哪些步骤来调试此问题?我假设这不是 Java 错误,而是 Web 服务器返回的内容的问题 - 但是我已经在我的 Web 浏览器中查看了该页面,并且还使用 curl 下载了它,两者都没有问题。
代码如下,应该很容易复制粘贴和独立运行:
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.logging.Logger;
public class HttpPageReader
{
private final static Logger logger = Logger.getLogger(HttpPageReader.class.getName());
private static final int SECOND_IN_MILLI_SECONDS = 1000;
private static final int TIME_OUT_MILLI_SECONDS = 10 * SECOND_IN_MILLI_SECONDS;
public static void main(String[] args)
{
if ( args.length != 1)
{
logger.warning("Please provide a url to download");
System.exit(1);
}
logger.info("Downloading url " + args[0] + "...");
try
{
URL url = new URL(args[0]);
HttpURLConnection httpConn = (HttpURLConnection) url.openConnection();
httpConn.setUseCaches(false);
httpConn.setRequestProperty("User-Agent", "My User Agent");
httpConn.setRequestProperty("Accept", "*/*");
httpConn.setConnectTimeout(TIME_OUT_MILLI_SECONDS);
httpConn.setReadTimeout(TIME_OUT_MILLI_SECONDS);
InputStreamReader inputStreamReader = new InputStreamReader(httpConn.getInputStream(), "utf-8");
char chars[] = new char[1000];
int numRead = inputStreamReader.read(chars);
StringBuffer stringBuffer = new StringBuffer();
while (numRead != -1)
{
stringBuffer.append(new String(chars, 0, numRead));
numRead = inputStreamReader.read(chars);
}
logger.info("done");
logger.info(stringBuffer.toString());
}
catch (Exception e)
{
e.printStackTrace();
}
}
}
更新:按照建议使用 IOUtils.toString(httpConn.getInputStream(), "utf-8") 给出了几乎相同的回溯 - 所以问题仍然存在,我该如何调试这个问题?
给出:
java.io.IOException: Premature EOF
at sun.net.www.http.ChunkedInputStream.readAheadBlocking(ChunkedInputStream.java:538)
at sun.net.www.http.ChunkedInputStream.readAhead(ChunkedInputStream.java:582)
at sun.net.www.http.ChunkedInputStream.read(ChunkedInputStream.java:669)
at java.io.FilterInputStream.read(FilterInputStream.java:116)
at sun.net.www.protocol.http.HttpURLConnection$HttpInputStream.read(HttpURLConnection.java:2668)
at sun.nio.cs.StreamDecoder.readBytes(StreamDecoder.java:264)
at sun.nio.cs.StreamDecoder.implRead(StreamDecoder.java:306)
at sun.nio.cs.StreamDecoder.read(StreamDecoder.java:158)
at java.io.InputStreamReader.read(InputStreamReader.java:167)
at java.io.Reader.read(Reader.java:123)
at org.apache.commons.io.IOUtils.copyLarge(IOUtils.java:1928)
at org.apache.commons.io.IOUtils.copyLarge(IOUtils.java:1907)
at org.apache.commons.io.IOUtils.copy(IOUtils.java:1884)
at org.apache.commons.io.IOUtils.copy(IOUtils.java:1834)
at org.apache.commons.io.IOUtils.toString(IOUtils.java:705)
at org.apache.commons.io.IOUtils.toString(IOUtils.java:730)
at HttpPageReader.main(HttpPageReader.java:40)