对象集合、对象数组、数组排序工具类

import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.math.BigDecimal;
import java.text.CollationKey;
import java.text.Collator;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.Date;
import java.util.List;

import org.apache.commons.lang.StringUtils;
import org.springframework.util.ReflectionUtils;

/**
 * 集合工具类
 * 
 * @author Duncan
 * 
 * @d2013-11-20
 */
public class CollectionUtil {

public final static String SORT_DESC = "desc";
public final static String SORT_ASC = "asc";

/**
 * 判断集合不为空
 * 
 * @param c
 * @return
 */
@SuppressWarnings("unchecked")
public static boolean isEmpty(Collection c) {
return c == null || c.size() == 0;
}

/**
 * List集合排序类
 * 
 * @param <T>
 * @param list
 *            集合
 * @param property
 *            排序字段名
 * @param sortType
 *            正序 (CollectionUtil.SORT_ASC)、倒序 (CollectionUtil.SORT_DESC)
 * @param isCN
 *            是否按中文排序
 */
public static <T> void sortList(List<T> list, final String property, final String sortType, final boolean isCN) {
Collections.sort(list, new Comparator<T>() {
private Collator collator = null;

public int compare(T a, T b) {
int ret = 0;
Field field = ReflectionUtils.findField(a.getClass(), property);
String getterMethodName = "get" + StringUtils.capitalize(property);
Method method = ReflectionUtils.findMethod(a.getClass(), getterMethodName);
Object value_a = ReflectionUtils.invokeMethod(method, a);
Object value_b = ReflectionUtils.invokeMethod(method, b);
if (field.getType() == String.class) {
if (isCN) {
collator = Collator.getInstance();
CollationKey key1 = collator.getCollationKey(value_a.toString());
CollationKey key2 = collator.getCollationKey(value_b.toString());
if (sortType != null && sortType.equals(CollectionUtil.SORT_DESC))
ret = key2.compareTo(key1);
else
ret = key1.compareTo(key2);
} else {
if (sortType != null && sortType.equals(CollectionUtil.SORT_DESC))
ret = value_b.toString().compareTo(value_a.toString());
else
ret = value_a.toString().compareTo(value_b.toString());
}
} else if (field.getType() == Integer.class || field.getType() == Long.class || field.getType() == BigDecimal.class) {
BigDecimal decA = new BigDecimal(value_a.toString());
BigDecimal decB = new BigDecimal(value_b.toString());
if (sortType != null && sortType.equals(CollectionUtil.SORT_DESC))
ret = decB.compareTo(decA);
else
ret = decA.compareTo(decB);
} else if (field.getType() == Date.class) {
if (sortType != null && sortType.equals(CollectionUtil.SORT_DESC))
ret = ((Date) value_b).compareTo((Date) value_a);
else
ret = ((Date) value_a).compareTo((Date) value_b);
}
return ret;
}
});
}

/**
 * 对象数组排序
 * 
 * @param <T>
 * @param array
 *            对象数组
 * @param property
 *            排序字段名
 * @param sortType
 *            正序 (CollectionUtil.SORT_ASC)、倒序 (CollectionUtil.SORT_DESC)
 * @param isCN
 *            是否按中文排序
 */
public static <T> void sortObjectArray(T[] array, final String property, final String sortType, final boolean isCN) {
Arrays.sort(array, new Comparator<T>() {
private Collator collator = null;
public int compare(T a, T b) {
int ret = 0;
Field field = ReflectionUtils.findField(a.getClass(), property);
String getterMethodName = "get" + StringUtils.capitalize(property);
Method method = ReflectionUtils.findMethod(a.getClass(), getterMethodName);
Object value_a = ReflectionUtils.invokeMethod(method, a);
Object value_b = ReflectionUtils.invokeMethod(method, b);
if (field.getType() == String.class) {
if (isCN) {
collator = Collator.getInstance();
CollationKey key1 = collator.getCollationKey(value_a.toString());
CollationKey key2 = collator.getCollationKey(value_b.toString());
if (sortType != null && sortType.equals(CollectionUtil.SORT_DESC))
ret = key2.compareTo(key1);
else
ret = key1.compareTo(key2);
} else {
if (sortType != null && sortType.equals(CollectionUtil.SORT_DESC))
ret = value_b.toString().compareTo(value_a.toString());
else
ret = value_a.toString().compareTo(value_b.toString());
}
} else if (field.getType() == Integer.class || field.getType() == Long.class || field.getType() == BigDecimal.class) {
BigDecimal decA = new BigDecimal(value_a.toString());
BigDecimal decB = new BigDecimal(value_b.toString());
if (sortType != null && sortType.equals(CollectionUtil.SORT_DESC))
ret = decB.compareTo(decA);
else
ret = decA.compareTo(decB);
} else if (field.getType() == Date.class) {
if (sortType != null && sortType.equals(CollectionUtil.SORT_DESC))
ret = ((Date) value_b).compareTo((Date) value_a);
else
ret = ((Date) value_a).compareTo((Date) value_b);
}
return ret;
}
});
}

/**
 * 数组排序
 * @param <T>
 * @param array
 * 要排序的数组
 * @param isCN
 * 是否按中文排序
 * @param sortType
 * 正序 (CollectionUtil.SORT_ASC)、倒序 (CollectionUtil.SORT_DESC)
 */
public static <T> void sortArray(T[] array, final boolean isCN, final String sortType) {
if (sortType != null && sortType.equals(CollectionUtil.SORT_DESC)) {
if (isCN) {
Arrays.sort(array, Collections.reverseOrder(Collator.getInstance(java.util.Locale.CHINA)));
} else {
Arrays.sort(array, Collections.reverseOrder());
}
} else {
if (isCN) {
Arrays.sort(array, Collator.getInstance(java.util.Locale.CHINA));
} else {
Arrays.sort(array);
}
}
}

//public static void main(String[] args) {
//User[] arrays = new User[3];
//User user = new User();
//user.setId(Long.valueOf(1111));
//user.setStrName("张三");
//user.setStrPwd("123456");
//arrays[0] = user;
//user = new User();
//user.setId(Long.valueOf(2222));
//user.setStrName("李四");
//user.setStrPwd("234567");
//arrays[1] = user;
//user = new User();
//user.setId(Long.valueOf(3333));
//user.setStrName("王五");
//user.setStrPwd("345678");
//arrays[2] = user;
//CollectionUtil.sortObjectArray(arrays, "strName", SORT_ASC, true);
//for (User po : arrays) {
//System.out.println(po.toString());
//}
//
//String[] newArray = { "中山", "汕头", "广州", "安庆", "阳江", "南京", "武汉", "北京", "安阳", "北方" };
//CollectionUtil.sortArray(newArray, true, SORT_DESC);
//for (String i : newArray) {
//System.out.print(i + "  ");
//}
//}
}