我使用运行android-7 (2.1)的模拟器和运行android-8 (2.2)的moto-defy来使用一个简单的android应用程序。
我遇到了一个有趣的问题,CSV解析应用程序在模拟器上失败了,但在defy和常规java应用程序(使用sun java)上成功了。
我追踪到了这个问题,原因是android-7的StringReader实现不支持负跳过操作:
Android-7:
/**
* Skips {@code amount} characters in the source string. Subsequent calls of
* {@code read} methods will not return these characters unless {@code
* reset()} is used.
*
* @param ns
* the maximum number of characters to skip.
* @return the number of characters actually skipped or 0 if {@code ns < 0}.
* @throws IOException
* if this reader is closed.
* @see #mark(int)
* @see #markSupported()
* @see #reset()
*/
@Override
public long skip(long ns) throws IOException {
synchronized (lock) {
if (isClosed()) {
throw new IOException(Msg.getString("K0083")); //$NON-NLS-1$
}
if (ns <= 0) {
return 0;
}
long skipped = 0;
if (ns < this.count - pos) {
pos = pos + (int) ns;
skipped = ns;
} else {
skipped = this.count - pos;
pos = this.count;
}
return skipped;
}
}J2SE 1.6:
/**
* Skips the specified number of characters in the stream. Returns
* the number of characters that were skipped.
*
* <p>The <code>ns</code> parameter may be negative, even though the
* <code>skip</code> method of the {@link Reader} superclass throws
* an exception in this case. Negative values of <code>ns</code> cause the
* stream to skip backwards. Negative return values indicate a skip
* backwards. It is not possible to skip backwards past the beginning of
* the string.
*
* <p>If the entire string has been read or skipped, then this method has
* no effect and always returns 0.
*
* @exception IOException If an I/O error occurs
*/
public long skip(long ns) throws IOException {
synchronized (lock) {
ensureOpen();
if (next >= length)
return 0;
// Bound skip by beginning and end of the source
long n = Math.min(length - next, ns);
n = Math.max(-next, n);
next += n;
return n;
}
}因此,android版本不会向后跳过(解析器在某些情况下会使用它来预读字符),而是保持向前一个字符。
我的问题是,J2SE规范的各种不兼容性和变体是否有文档记录?如果没有,你们还遇到了什么其他问题。
谢谢你,p。
发布于 2011-07-17 13:43:40
一个值得关注的地方是Android问题跟踪器。
另一个值得关注的地方是Apache Harmony问题跟踪器。
诚然,使用问题跟踪器将涉及搜索,而不是浏览仔细分类的问题的网络。你可以把这看作是一个机会。
搜索和谐问题跟踪器显示,在不同的流类中,skip的行为存在一些问题。一个问题抱怨说,某些类的行为与javadoc不匹配……这是关闭的,因为它确实符合RI的行为,因此错误存在于javadoc中。
我的观点是,Sun / Oracle对这类事情承担了很大责任,因为他们拒绝以合理的条款将TCK授权给Apache Harmony项目。
https://stackoverflow.com/questions/6721928
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