import java.lang.reflect.Field;
import java.text.NumberFormat;
import java.util.Collections;
import java.util.Comparator;
import java.util.Date;
import java.util.List;
public class ListUtils {
public static void sort(List list, final boolean isAsc, final String... sortnameArr) {
Collections.sort(list, new Comparator() {
public int compare(E a, E b) {
int ret = 0;
try {
for (int i = 0; i < sortnameArr.length; i++) {
ret = ListUtils.compareObject(sortnameArr[i], isAsc, a, b);
if (0 != ret) {
break;
}
}
} catch (Exception e) {
e.printStackTrace();
}
return ret;
}
});
}
public static void sort(List list, final String[] sortnameArr, final boolean[] typeArr) {
if (sortnameArr.length != typeArr.length) {
throw new RuntimeException("属性数组元素个数和升降序数组元素个数不相等");
}
Collections.sort(list, new Comparator() {
public int compare(E a, E b) {
int ret = 0;
try {
for (int i = 0; i < sortnameArr.length; i++) {
ret = ListUtils.compareObject(sortnameArr[i], typeArr[i], a, b);
if (0 != ret) {
break;
}
}
} catch (Exception e) {
e.printStackTrace();
}
return ret;
}
});
}
private static int compareObject(final String sortname, final boolean isAsc, E a, E b) throws Exception {
int ret;
Object value1 = ListUtils.forceGetFieldValue(a, sortname);
Object value2 = ListUtils.forceGetFieldValue(b, sortname);
String str1 = value1.toString();
String str2 = value2.toString();
if (value1 instanceof Number && value2 instanceof Number) {
int maxlen = Math.max(str1.length(), str2.length());
str1 = ListUtils.addZero2Str((Number) value1, maxlen);
str2 = ListUtils.addZero2Str((Number) value2, maxlen);
} else if (value1 instanceof Date && value2 instanceof Date) {
long time1 = ((Date) value1).getTime();
long time2 = ((Date) value2).getTime();
int maxlen = Long.toString(Math.max(time1, time2)).length();
str1 = ListUtils.addZero2Str(time1, maxlen);
str2 = ListUtils.addZero2Str(time2, maxlen);
}
if (isAsc) {
ret = str1.compareTo(str2);
} else {
ret = str2.compareTo(str1);
}
return ret;
}
public static String addZero2Str(Number numObj, int length) {
NumberFormat nf = NumberFormat.getInstance();
// 设置是否使用分组
nf.setGroupingUsed(false);
// 设置最大整数位数
nf.setMaximumIntegerDigits(length);
// 设置最小整数位数
nf.setMinimumIntegerDigits(length);
return nf.format(numObj);
}
public static Object forceGetFieldValue(Object obj, String fieldName) throws Exception {
Field field = obj.getClass().getDeclaredField(fieldName);
Object object = null;
boolean accessible = field.isAccessible();
if (!accessible) {
// 如果是private,protected修饰的属性，需要修改为可以访问的
field.setAccessible(true);
object = field.get(obj);
// 还原private,protected属性的访问性质
field.setAccessible(accessible);
return object;
}
object = field.get(obj);
return object;
}