Java by API/java.lang/Field
Содержание
Field: getModifiers()
<source lang="java">
/* ArrayList, serialVersionUID, long, private static final ArrayList, elementData, [Ljava.lang.Object;, private transient ArrayList, size, int, private Arrays, INSERTIONSORT_THRESHOLD, int, private static final BitSet, ADDRESS_BITS_PER_UNIT, int, private static final BitSet, BITS_PER_UNIT, int, private static final BitSet, BIT_INDEX_MASK, int, private static final BitSet, WORD_MASK, long, private static final BitSet, bits, [J, private BitSet, unitsInUse, int, private transient BitSet, serialVersionUID, long, private static final BitSet, trailingZeroTable, [B, private static final Collections, BINARYSEARCH_THRESHOLD, int, private static final Collections, REVERSE_THRESHOLD, int, private static final Collections, SHUFFLE_THRESHOLD, int, private static final Collections, FILL_THRESHOLD, int, private static final Collections, ROTATE_THRESHOLD, int, private static final Collections, COPY_THRESHOLD, int, private static final Collections, REPLACEALL_THRESHOLD, int, private static final Collections, INDEXOFSUBLIST_THRESHOLD, int, private static final Collections, r, java.util.Random, private static Collections, EMPTY_SET, java.util.Set, public static final Collections, EMPTY_LIST, java.util.List, public static final Collections, EMPTY_MAP, java.util.Map, public static final Collections, REVERSE_ORDER, java.util.ruparator, private static final HashMap, DEFAULT_INITIAL_CAPACITY, int, static final HashMap, MAXIMUM_CAPACITY, int, static final HashMap, DEFAULT_LOAD_FACTOR, float, static final HashMap, table, [Ljava.util.HashMap$Entry;, transient HashMap, size, int, transient HashMap, threshold, int, HashMap, loadFactor, float, final HashMap, modCount, int, transient volatile HashMap, NULL_KEY, java.lang.Object, static final HashMap, entrySet, java.util.Set, private transient HashMap, serialVersionUID, long, private static final HashSet, serialVersionUID, long, static final HashSet, map, java.util.HashMap, private transient HashSet, PRESENT, java.lang.Object, private static final WeakHashMap, DEFAULT_INITIAL_CAPACITY, int, private static final WeakHashMap, MAXIMUM_CAPACITY, int, private static final WeakHashMap, DEFAULT_LOAD_FACTOR, float, private static final WeakHashMap, table, [Ljava.util.WeakHashMap$Entry;, private WeakHashMap, size, int, private WeakHashMap, threshold, int, private WeakHashMap, loadFactor, float, private final WeakHashMap, queue, java.lang.ref.ReferenceQueue, private final WeakHashMap, modCount, int, private volatile WeakHashMap, NULL_KEY, java.lang.Object, private static final WeakHashMap, entrySet, java.util.Set, private transient
* **/
import java.lang.reflect.Field; import java.lang.reflect.Modifier; public class MainClass {
public static void main(String args[]) throws Exception {
String names[] = { "ArrayList", "Arrays", "BitSet", "Collection", "Collections", "Dictionary",
"Enumeration", "HashMap", "HashSet", "WeakHashMap" };
for (int i = 0, n = names.length; i < n; i++) {
String className = "java.util." + names[i];
Class theClass = Class.forName(className);
Field fields[] = theClass.getDeclaredFields();
for (int j = 0, m = fields.length; j < m; j++) {
System.out.println(names[i] + ", " + fields[j].getName() + ", "
+ fields[j].getType().getName() + ", " + Modifier.toString(fields[j].getModifiers()));
}
}
}
}
</source>
Field: getName()
<source lang="java">
/* ArrayList, serialVersionUID, long, private static final ArrayList, elementData, [Ljava.lang.Object;, private transient ArrayList, size, int, private Arrays, INSERTIONSORT_THRESHOLD, int, private static final BitSet, ADDRESS_BITS_PER_UNIT, int, private static final BitSet, BITS_PER_UNIT, int, private static final BitSet, BIT_INDEX_MASK, int, private static final BitSet, WORD_MASK, long, private static final BitSet, bits, [J, private BitSet, unitsInUse, int, private transient BitSet, serialVersionUID, long, private static final BitSet, trailingZeroTable, [B, private static final Collections, BINARYSEARCH_THRESHOLD, int, private static final Collections, REVERSE_THRESHOLD, int, private static final Collections, SHUFFLE_THRESHOLD, int, private static final Collections, FILL_THRESHOLD, int, private static final Collections, ROTATE_THRESHOLD, int, private static final Collections, COPY_THRESHOLD, int, private static final Collections, REPLACEALL_THRESHOLD, int, private static final Collections, INDEXOFSUBLIST_THRESHOLD, int, private static final Collections, r, java.util.Random, private static Collections, EMPTY_SET, java.util.Set, public static final Collections, EMPTY_LIST, java.util.List, public static final Collections, EMPTY_MAP, java.util.Map, public static final Collections, REVERSE_ORDER, java.util.ruparator, private static final HashMap, DEFAULT_INITIAL_CAPACITY, int, static final HashMap, MAXIMUM_CAPACITY, int, static final HashMap, DEFAULT_LOAD_FACTOR, float, static final HashMap, table, [Ljava.util.HashMap$Entry;, transient HashMap, size, int, transient HashMap, threshold, int, HashMap, loadFactor, float, final HashMap, modCount, int, transient volatile HashMap, NULL_KEY, java.lang.Object, static final HashMap, entrySet, java.util.Set, private transient HashMap, serialVersionUID, long, private static final HashSet, serialVersionUID, long, static final HashSet, map, java.util.HashMap, private transient HashSet, PRESENT, java.lang.Object, private static final WeakHashMap, DEFAULT_INITIAL_CAPACITY, int, private static final WeakHashMap, MAXIMUM_CAPACITY, int, private static final WeakHashMap, DEFAULT_LOAD_FACTOR, float, private static final WeakHashMap, table, [Ljava.util.WeakHashMap$Entry;, private WeakHashMap, size, int, private WeakHashMap, threshold, int, private WeakHashMap, loadFactor, float, private final WeakHashMap, queue, java.lang.ref.ReferenceQueue, private final WeakHashMap, modCount, int, private volatile WeakHashMap, NULL_KEY, java.lang.Object, private static final WeakHashMap, entrySet, java.util.Set, private transient
* **/
import java.lang.reflect.Field; import java.lang.reflect.Modifier; public class MainClass {
public static void main(String args[]) throws Exception {
String names[] = { "ArrayList", "Arrays", "BitSet", "Collection", "Collections", "Dictionary",
"Enumeration", "HashMap", "HashSet", "WeakHashMap" };
for (int i = 0, n = names.length; i < n; i++) {
String className = "java.util." + names[i];
Class theClass = Class.forName(className);
Field fields[] = theClass.getDeclaredFields();
for (int j = 0, m = fields.length; j < m; j++) {
System.out.println(names[i] + ", " + fields[j].getName() + ", "
+ fields[j].getType().getName() + ", " + Modifier.toString(fields[j].getModifiers()));
}
}
}
}
</source>
Field: getType()
<source lang="java">
/* ArrayList, serialVersionUID, long, private static final ArrayList, elementData, [Ljava.lang.Object;, private transient ArrayList, size, int, private Arrays, INSERTIONSORT_THRESHOLD, int, private static final BitSet, ADDRESS_BITS_PER_UNIT, int, private static final BitSet, BITS_PER_UNIT, int, private static final BitSet, BIT_INDEX_MASK, int, private static final BitSet, WORD_MASK, long, private static final BitSet, bits, [J, private BitSet, unitsInUse, int, private transient BitSet, serialVersionUID, long, private static final BitSet, trailingZeroTable, [B, private static final Collections, BINARYSEARCH_THRESHOLD, int, private static final Collections, REVERSE_THRESHOLD, int, private static final Collections, SHUFFLE_THRESHOLD, int, private static final Collections, FILL_THRESHOLD, int, private static final Collections, ROTATE_THRESHOLD, int, private static final Collections, COPY_THRESHOLD, int, private static final Collections, REPLACEALL_THRESHOLD, int, private static final Collections, INDEXOFSUBLIST_THRESHOLD, int, private static final Collections, r, java.util.Random, private static Collections, EMPTY_SET, java.util.Set, public static final Collections, EMPTY_LIST, java.util.List, public static final Collections, EMPTY_MAP, java.util.Map, public static final Collections, REVERSE_ORDER, java.util.ruparator, private static final HashMap, DEFAULT_INITIAL_CAPACITY, int, static final HashMap, MAXIMUM_CAPACITY, int, static final HashMap, DEFAULT_LOAD_FACTOR, float, static final HashMap, table, [Ljava.util.HashMap$Entry;, transient HashMap, size, int, transient HashMap, threshold, int, HashMap, loadFactor, float, final HashMap, modCount, int, transient volatile HashMap, NULL_KEY, java.lang.Object, static final HashMap, entrySet, java.util.Set, private transient HashMap, serialVersionUID, long, private static final HashSet, serialVersionUID, long, static final HashSet, map, java.util.HashMap, private transient HashSet, PRESENT, java.lang.Object, private static final WeakHashMap, DEFAULT_INITIAL_CAPACITY, int, private static final WeakHashMap, MAXIMUM_CAPACITY, int, private static final WeakHashMap, DEFAULT_LOAD_FACTOR, float, private static final WeakHashMap, table, [Ljava.util.WeakHashMap$Entry;, private WeakHashMap, size, int, private WeakHashMap, threshold, int, private WeakHashMap, loadFactor, float, private final WeakHashMap, queue, java.lang.ref.ReferenceQueue, private final WeakHashMap, modCount, int, private volatile WeakHashMap, NULL_KEY, java.lang.Object, private static final WeakHashMap, entrySet, java.util.Set, private transient
* **/
import java.lang.reflect.Field; import java.lang.reflect.Modifier; public class MainClass {
public static void main(String args[]) throws Exception {
String names[] = { "ArrayList", "Arrays", "BitSet", "Collection", "Collections", "Dictionary",
"Enumeration", "HashMap", "HashSet", "WeakHashMap" };
for (int i = 0, n = names.length; i < n; i++) {
String className = "java.util." + names[i];
Class theClass = Class.forName(className);
Field fields[] = theClass.getDeclaredFields();
for (int j = 0, m = fields.length; j < m; j++) {
System.out.println(names[i] + ", " + fields[j].getName() + ", "
+ fields[j].getType().getName() + ", " + Modifier.toString(fields[j].getModifiers()));
}
}
}
}
</source>
Field: setAccessible(boolean flag)
<source lang="java">
import java.lang.reflect.Field; public class Main {
public static void initIntFields(final Object obj) {
try {
Field[] fields = obj.getClass().getDeclaredFields();
for (int idx = 0; idx < fields.length; idx++) {
if (fields[idx].getType() == int.class) {
fields[idx].setAccessible(true);
fields[idx].setInt(obj, 0);
}
}
} catch (final IllegalAccessException ex) {
throw new RuntimeException(ex);
}
}
public static final void main(final String[] args) {
Integer value = new Integer("123");
System.out.println("Before: " + value);
initIntFields(value);
System.out.println("After: " + value);
}
}
</source>
