本文整理了Java中java.util.Hashtable.keys()方法的一些代码示例，展示了Hashtable.keys()的具体用法。这些代码示例主要来源于Github/Stackoverflow/Maven等平台，是从一些精选项目中提取出来的代码，具有较强的参考意义，能在一定程度帮忙到你。Hashtable.keys()方法的具体详情如下：
包路径：java.util.Hashtable
类名称：Hashtable
方法名：keys

Hashtable.keys介绍

[英]Returns an enumeration on the keys of this Hashtable instance. The results of the enumeration may be affected if the contents of this Hashtable are modified.
[中]返回此哈希表实例的键的枚举。如果修改此哈希表的内容，枚举结果可能会受到影响。

代码示例

代码示例来源：origin: log4j/log4j

public SortedKeyEnumeration(Hashtable ht) {
 Enumeration f = ht.keys();
 Vector keys = new Vector(ht.size());
 for (int i, last = 0; f.hasMoreElements(); ++last) {
  String key = (String) f.nextElement();
  for (i = 0; i < last; ++i) {
   String s = (String) keys.get(i);
   if (key.compareTo(s) <= 0) break;
  }
  keys.add(i, key);
 }
 e = keys.elements();
}

代码示例来源：origin: stackoverflow.com

Hashtable<Integer, String> table = ...

Enumeration<Integer> enumKey = table.keys();
while(enumKey.hasMoreElements()) {
  Integer key = enumKey.nextElement();
  String val = table.get(key);
  if(key==0 && val.equals("0"))
    table.remove(key);
}

代码示例来源：origin: org.slf4j/jcl-over-slf4j

/**
 * Return an array containing the names of all currently defined configuration
 * attributes. If there are no such attributes, a zero length array is
 * returned.
 */
@SuppressWarnings("unchecked")
public String[] getAttributeNames() {
  List<String> names = new ArrayList<String>();
  Enumeration<String> keys = attributes.keys();
  while (keys.hasMoreElements()) {
    names.add((String) keys.nextElement());
  }
  String results[] = new String[names.size()];
  for (int i = 0; i < results.length; i++) {
    results[i] = (String) names.get(i);
  }
  return (results);
}

代码示例来源：origin: gocd/gocd

private void setupClassesInBundle(String... classes) throws MalformedURLException, ClassNotFoundException {
  Hashtable<URL, String> classFileEntries = new Hashtable<>();
  for (String aClass : classes) {
    classFileEntries.put(new URL("file:///" + aClass), "");
  }
  when(bundle.findEntries("/", "*.class", true)).thenReturn(classFileEntries.keys());
}

代码示例来源：origin: commons-collections/commons-collections

public void testToListWithHashtable() {
  Hashtable expected = new Hashtable();
  expected.put("one", new Integer(1));
  expected.put("two", new Integer(2));
  expected.put("three", new Integer(3));
  // validate elements.
  List actualEltList = EnumerationUtils.toList(expected.elements());
  Assert.assertEquals(expected.size(), actualEltList.size());
  Assert.assertTrue(actualEltList.contains(new Integer(1)));
  Assert.assertTrue(actualEltList.contains(new Integer(2)));
  Assert.assertTrue(actualEltList.contains(new Integer(3)));
  List expectedEltList = new ArrayList();
  expectedEltList.add(new Integer(1));
  expectedEltList.add(new Integer(2));
  expectedEltList.add(new Integer(3));
  Assert.assertTrue(actualEltList.containsAll(expectedEltList));
  // validate keys.
  List actualKeyList = EnumerationUtils.toList(expected.keys());
  Assert.assertEquals(expected.size(), actualEltList.size());
  Assert.assertTrue(actualKeyList.contains("one"));
  Assert.assertTrue(actualKeyList.contains("two"));
  Assert.assertTrue(actualKeyList.contains("three"));
  List expectedKeyList = new ArrayList();
  expectedKeyList.add("one");
  expectedKeyList.add("two");
  expectedKeyList.add("three");
  Assert.assertTrue(actualKeyList.containsAll(expectedKeyList));
}

代码示例来源：origin: stackoverflow.com

private static String getPostParamString(Hashtable<String, String> params) {
  if(params.size() == 0)
    return "";

  StringBuffer buf = new StringBuffer();
  Enumeration<String> keys = params.keys();
  while(keys.hasMoreElements()) {
    buf.append(buf.length() == 0 ? "" : "&");
    String key = keys.nextElement();
    buf.append(key).append("=").append(params.get(key));
  }
  return buf.toString();
}

代码示例来源：origin: wildfly/wildfly

/**
 * Return an array containing the names of all currently defined configuration
 * attributes. If there are no such attributes, a zero length array is
 * returned.
 */
@SuppressWarnings("unchecked")
public String[] getAttributeNames() {
  List<String> names = new ArrayList<String>();
  Enumeration<String> keys = attributes.keys();
  while (keys.hasMoreElements()) {
    names.add((String) keys.nextElement());
  }
  String results[] = new String[names.size()];
  for (int i = 0; i < results.length; i++) {
    results[i] = (String) names.get(i);
  }
  return (results);
}

代码示例来源：origin: spring-projects/spring-framework

@Test
public void testContains() {
  assertFalse(CollectionUtils.contains((Iterator<String>) null, "myElement"));
  assertFalse(CollectionUtils.contains((Enumeration<String>) null, "myElement"));
  assertFalse(CollectionUtils.contains(new LinkedList<String>().iterator(), "myElement"));
  assertFalse(CollectionUtils.contains(new Hashtable<String, Object>().keys(), "myElement"));
  List<String> list = new LinkedList<>();
  list.add("myElement");
  assertTrue(CollectionUtils.contains(list.iterator(), "myElement"));
  Hashtable<String, String> ht = new Hashtable<>();
  ht.put("myElement", "myValue");
  assertTrue(CollectionUtils.contains(ht.keys(), "myElement"));
}

代码示例来源：origin: pentaho/pentaho-kettle

public String[] getUsedFields() {
 Hashtable<String, String> fields = new Hashtable<String, String>();
 getUsedFields( fields );
 String[] retval = new String[fields.size()];
 Enumeration<String> keys = fields.keys();
 int i = 0;
 while ( keys.hasMoreElements() ) {
  retval[i] = keys.nextElement();
  i++;
 }
 return retval;
}

代码示例来源：origin: robovm/robovm

/**
 * Return an array containing the names of all currently defined
 * configuration attributes.  If there are no such attributes, a zero
 * length array is returned.
 */
public String[] getAttributeNames() {
  Vector names = new Vector();
  Enumeration keys = attributes.keys();
  while (keys.hasMoreElements()) {
    names.addElement((String) keys.nextElement());
  }
  String results[] = new String[names.size()];
  for (int i = 0; i < results.length; i++) {
    results[i] = (String) names.elementAt(i);
  }
  return (results);
}

代码示例来源：origin: oblac/jodd

@Test
void testAsIterator_with_data() throws Exception {
  final Hashtable<String, String> input = new Hashtable<>();
  input.put("jodd", "makes fun!");
  input.put("headline", "The Unbearable Lightness of Java");
  input.put("aim", "And enjoy the coding");
  final Iterator<String> actual = CollectionUtil.asIterator(input.keys());
  // asserts
  assertNotNull(actual);
  // next #1
  assertTrue(actual.hasNext());
  String key = actual.next();
  assertTrue(input.containsKey(key));
  // next #2
  assertTrue(actual.hasNext());
  key = actual.next();
  assertTrue(input.containsKey(key));
  // next #3
  assertTrue(actual.hasNext());
  key = actual.next();
  assertTrue(input.containsKey(key));
  // no more elements
  assertFalse(actual.hasNext());
  assertThrows(NoSuchElementException.class, () -> {actual.next();});
}

代码示例来源：origin: xalan/xalan

private void appendTemplateCode(InstructionList body) {
final Enumeration templates = _neededTemplates.keys();
while (templates.hasMoreElements()) {
  final Object iList =
  _templateILs.get(templates.nextElement());
  if (iList != null) {
  body.append((InstructionList)iList);
  }
}
}

代码示例来源：origin: robovm/robovm

MappingRecord getMappingFromURI(String uri)
{
  MappingRecord foundMap = null;
  Enumeration prefixes = m_namespaces.keys();
  while (prefixes.hasMoreElements())
  {
    String prefix = (String) prefixes.nextElement();
    MappingRecord map2 = getMappingFromPrefix(prefix);
    if (map2 != null && (map2.m_uri).equals(uri))
    {
      foundMap = map2;
      break;
    }
  }
  return foundMap;
}

代码示例来源：origin: i2p/i2p.i2p

/**
 * @return List of request parameter names
 * @throws IllegalStateException if the request is too large
 */
public Enumeration<String> getParameterNames() {
  if (isMultiPartRequest) {
    if( cachedParameterNames == null ) {
      cachedParameterNames = new Hashtable<String, Integer>();
      try {
        Integer DUMMY = Integer.valueOf(0);
        for (Part p : httpRequest.getParts()) {
          cachedParameterNames.put(p.getName(), DUMMY);
        }
      } catch (IOException ioe) {
        log(ioe);
      } catch (ServletException se) {
        log(se);
      } catch (IllegalStateException ise) {
        log(ise);
        throw ise;
      }
    }
    return cachedParameterNames.keys();
  } else {
    return httpRequest.getParameterNames();
  }
}

代码示例来源：origin: log4j/log4j

Enumeration enumeration = ht.keys();
 while(enumeration.hasMoreElements() && (misses <= 4)) {
Thread t = (Thread) enumeration.nextElement();
if(t.isAlive()) {
 misses++;
 Thread t = (Thread) v.elementAt(i);
 LogLog.debug("Lazy NDC removal for thread [" + t.getName() + "] ("+ 
    ht.size() + ").");
 ht.remove(t);

代码示例来源：origin: robovm/robovm

/**
 * Given a namespace uri, and the namespaces mappings for the 
 * current element, return the current prefix for that uri.
 * 
 * @param uri the namespace URI to be search for
 * @return an existing prefix that maps to the given URI, null if no prefix
 * maps to the given namespace URI.
 */
public String lookupPrefix(String uri)
{
  String foundPrefix = null;
  Enumeration prefixes = m_namespaces.keys();
  while (prefixes.hasMoreElements())
  {
    String prefix = (String) prefixes.nextElement();
    String uri2 = lookupNamespace(prefix);
    if (uri2 != null && uri2.equals(uri))
    {
      foundPrefix = prefix;
      break;
    }
  }
  return foundPrefix;
}

代码示例来源：origin: plutext/docx4j

/**
 * Removes the mapping associated to the specified prefix.
 *
 * @param prefix The prefix which mapping should be removed.
 */
private void removeIfNeeded(String prefix) {
 // remove the previous mapping to the prefix
 if (this.prefixMapping.containsValue(prefix)) {
  Object key = null;
  for (Enumeration<String> e = this.prefixMapping.keys(); e.hasMoreElements();) {
   key = e.nextElement();
   if (this.prefixMapping.get(key).equals(prefix)) {
    break;
   }
  }
  this.prefixMapping.remove(key); // we know key should have a value
 }
}

代码示例来源：origin: robovm/robovm

/**
   * Given a namespace uri, get all prefixes bound to the Namespace URI in the current scope. 
   * 
   * @param uri the namespace URI to be search for
   * @return An array of Strings which are
   * all prefixes bound to the namespace URI in the current scope.
   * An array of zero elements is returned if no prefixes map to the given
   * namespace URI.
   */
  public String[] lookupAllPrefixes(String uri)
  {
    java.util.ArrayList foundPrefixes = new java.util.ArrayList();
    Enumeration prefixes = m_namespaces.keys();
    while (prefixes.hasMoreElements())
    {
      String prefix = (String) prefixes.nextElement();
      String uri2 = lookupNamespace(prefix);
      if (uri2 != null && uri2.equals(uri))
      {
        foundPrefixes.add(prefix);
      }
    }
    String[] prefixArray = new String[foundPrefixes.size()];
    foundPrefixes.toArray(prefixArray);
    return prefixArray;
  }
}

代码示例来源：origin: xalan/xalan

/**
 * This method starts at a given node, traverses all namespace mappings,
 * and assembles a list of all prefixes that (for the given node) maps
 * to _ANY_ namespace URI. Used by literal result elements to determine
 */
public Enumeration getNamespaceScope(SyntaxTreeNode node) {
Hashtable all = new Hashtable();

while (node != null) {
  Hashtable mapping = node.getPrefixMapping();
  if (mapping != null) {
  Enumeration prefixes = mapping.keys();
  while (prefixes.hasMoreElements()) {
    String prefix = (String)prefixes.nextElement();
    if (!all.containsKey(prefix)) {
    all.put(prefix, mapping.get(prefix));
    }
  }
  }
  node = node.getParent();
}
return(all.keys());
}

代码示例来源：origin: pentaho/pentaho-kettle

/**
 * Clear out all entries of database with a certain name
 *
 * @param dbname
 *          The name of the database for which we want to clear the cache or null if we want to clear it all.
 */
public void clear( String dbname ) {
 if ( dbname == null ) {
  cache = new Hashtable<DBCacheEntry, RowMetaInterface>();
  setActive();
 } else {
  Enumeration<DBCacheEntry> keys = cache.keys();
  while ( keys.hasMoreElements() ) {
   DBCacheEntry entry = keys.nextElement();
   if ( entry.sameDB( dbname ) ) {
    // Same name: remove it!
    cache.remove( entry );
   }
  }
 }
}