/**
* Constructs a property-based comparator for beans. This constructor creates a BeanComparator
* that uses the supplied Comparator to compare the property values.
*
* @param property Name of a bean property, can contain the name of a simple, nested, indexed,
* mapped, or combined property. See {@link PropertyUtilsBean} for property query language
* syntax.
* @param comparator BeanComparator will pass the values of the specified bean property to this
* Comparator. If your bean property is not a comparable or contains null values, a suitable
* comparator may be supplied in this constructor.
*/
public BeanComparator(String property, Comparator comparator) {
setProperty(property);
if (comparator != null) {
this.comparator = comparator;
} else {
this.comparator = ComparableComparator.getInstance();
}
}
@SuppressWarnings({"unchecked", "rawtypes"})
public static void main(String[] args) {
List<User> list = new ArrayList<User>();
list.add(new User(2, "姚郁", 28));
list.add(new User(1, "孟志昂", 25));
list.add(new User(3, "矿宗义", 30));
list.add(new User(4, "王仕强", 25));
System.out.println("-----排序前-----");
for (User u : list) {
System.out.println(u.name + "/" + u.age);
}
System.out.println("-----满足：先按age升序排列，再按id降序排列-----");
List sortFields = new ArrayList();
Comparator mycmp = ComparableComparator.getInstance();
mycmp = ComparatorUtils.reversedComparator(mycmp);
sortFields.add(new BeanComparator("age"));
sortFields.add(new BeanComparator("id", mycmp));
ComparatorChain multiSort = new ComparatorChain(sortFields);
Collections.sort(list, multiSort);
for (User u : list) {
System.out.println(u.id + "/" + u.name + "/" + u.age);
}
}
/**
* Constructs a property-based comparator for beans. This compares two beans by the property
* specified in the property parameter. This constructor creates a <code>BeanComparator</code>
* that uses a <code>ComparableComparator</code> to compare the property values.
*
* <p>Passing "null" to this constructor will cause the BeanComparator to compare objects based on
* natural order, that is <code>java.lang.Comparable</code>.
*
* @param property String Name of a bean property, which may contain the name of a simple, nested,
* indexed, mapped, or combined property. See {@link PropertyUtilsBean} for property query
* language syntax. If the property passed in is null then the actual objects will be compared
*/
public BeanComparator(String property) {
this(property, ComparableComparator.getInstance());
}