我試圖使用在這裏提到的java的風向標: https://www.ibm.com/developerworks/java/library/j-benchmark2/ 並且可以在這裏下載: http://www.ellipticgroup.com/html/benchmarkingArticle.html的Java基準測試中Ellipticgroup /布倫特·博耶
我試圖用簡單的例子在文章上方:
import bb.util.Benchmark;
public class ShortIndexesLoop {
public static void main(String[] args) throws Exception {
Callable<Integer> task =
new Callable<Integer>() { public Integer call() { return fibonacci(35); } };
System.out.println("fibonacci(35): " + new Benchmark(task));
}
protected static int fibonacci(int n) throws IllegalArgumentException {
if (n < 0) throw new IllegalArgumentException("n = " + n + " < 0");
if (n <= 1) return n;
return fibonacci(n - 1) + fibonacci(n - 2);
}
}
但是這個基準的每一個執行它在運行基準測試之前,一個異常開始
6月13日,2015 1:45:37 PM StringUtil 警告:字符串行爲不像預期的那樣;看到引起
java.lang.Exception: substring does NOT share the same underlying char[] with its parent String
at bb.util.StringUtil.inspectStringConstructor(StringUtil.java:84)
at bb.util.StringUtil.<clinit>(StringUtil.java:75)
at bb.io.ConsoleUtil.<clinit>(ConsoleUtil.java:81)
at bb.util.Benchmark.sendUserMsg(Benchmark.java:1002)
at bb.util.Benchmark.osSpecificPreparation(Benchmark.java:579)
at bb.util.Benchmark.perform(Benchmark.java:541)
at bb.util.Benchmark.<init>(Benchmark.java:464)
at bb.util.Benchmark.<init>(Benchmark.java:439)
at ShortIndexesLoop.main(fib.java:13)
似乎到基準任何呼叫結束使用以下方法StringUtil
private static final boolean stringContructorTrimsGarbage = inspectStringConstructor();
private static boolean inspectStringConstructor() {
try {
// first prove that substring shares the same underlying char[] as the parent String:
String s1 = "abc123def";
String s2 = s1.substring(3, 6);
char[] value1 = (char[]) ReflectUtil.get(s1, "value");
char[] value2 = (char[]) ReflectUtil.get(s2, "value");
if (value1 != value2) throw new Exception("substring does NOT share the same underlying char[] with its parent String");
if (value2.length != s1.length()) throw new Exception("value2.length = " + value2.length + " != s1.length() = " + s1.length());
// second prove that the String(String) constructor trims garbage chars:
String s3 = new String(s2);
char[] value3 = (char[]) ReflectUtil.get(s3, "value");
if (value3 == value2) throw new Exception("new String shares the same underlying char[] with its String arg");
if (!(value3.length < value2.length)) throw new Exception("value3.length = " + value3.length + " is not < value2.length = " + value2.length);
return true;
}
catch (Exception e) {
LogUtil.getLogger2().logp(Level.WARNING, "StringUtil", "<clinit>", "String does not behave as expected; see cause", e);
return false;
}
}
我不介意例外,因爲基準庫做給一個結果。但是,試圖將此代碼編譯爲jar並將其作爲jar運行,這是一個問題。 由於例外其餘代碼將不會在終端執行
任何人都有任何想法如何解決這個問題?
可能與Java 7中的實現更改不兼容:http://java.dzone.com/articles/changes-stringsubstring-java-7 – Marvin
有沒有辦法在不更改爲java 1.6或1.8的情況下處理此問題? – Quantico
Java 8不會幫助,因爲此更改仍然存在。除此之外,您只能等待庫更新或嘗試自行修補它。編輯:或者嘗試一個不同的c庫,但我無法推薦,甚至不能提名。 – Marvin