<p>最近在做一個項目，裏邊有大量的排序需求，神煩！如果每個排序需求都做一個接口的話，那樣工作量就太大了，所以就要有一個通用一些的排序工具類，來解決排序問題。</p><p>由於排序需求很大一部分都是List集合排序，所以就從網上找了一個List<Object>集合排序工具類來使用，這個工具類可以很靈活的傳入需要排序的字段和需要的升序或者降序來排序。</p>
public class SortListUtil {
public static final String DESC = "desc";
public static final String ASC = "asc";
/**
* 對list中的元素按升序排列.
*
* @param list
* 排序集合
* @param field
* 排序字段
* @return
*/
public static List<?> sort(List<?> list, final String field) {
return sort(list, field, null);
}
/**
* 對list中的元素進行排序.
*
* @param list
* 排序集合
* @param field
* 排序字段
* @param sort
* 排序方式: SortList.DESC(降序) SortList.ASC(升序).
* @return
*/
@SuppressWarnings("unchecked")
public static List<?> sort(List<?> list, final String field,
final String sort) {
Collections.sort(list, new Comparator() {
public int compare(Object a, Object b) {
int ret = 0;
try {
Field f = null;
//a.getClass().getDeclaredField(field);只能獲取當前對象的字段，不能獲取父類的字段
//以下爲循環獲取父類的字段
Class<?> clazz = a.getClass() ;
for(; clazz != Object.class ; clazz = clazz.getSuperclass()) {
try {
f = clazz.getDeclaredField(field) ;
break;
} catch (Exception e) {
//這裏甚麼都不要做！並且這裏的異常必須這樣寫，不能拋出去。
//如果這裏的異常打印或者往外拋，則就不會執行clazz = clazz.getSuperclass(),最後就不會進入到父類中了
}
}
//Field f = a.getClass().getDeclaredField(field);
f.setAccessible(true);
Class<?> type = f.getType();
if (type == int.class) {
ret = ((Integer) f.getInt(a)).compareTo((Integer) f
.getInt(b));
} else if (type == double.class) {
ret = ((Double) f.getDouble(a)).compareTo((Double) f
.getDouble(b));
} else if (type == long.class) {
ret = ((Long) f.getLong(a)).compareTo((Long) f
.getLong(b));
} else if (type == float.class) {
ret = ((Float) f.getFloat(a)).compareTo((Float) f
.getFloat(b));
} else if (type == Date.class) {
ret = ((Date) f.get(a)).compareTo((Date) f.get(b));
} else if (isImplementsOf(type, Comparable.class)) {
ret = ((Comparable) f.get(a)).compareTo((Comparable) f
.get(b));
} else {
ret = String.valueOf(f.get(a)).compareTo(
String.valueOf(f.get(b)));
}
}catch (Exception e) {
e.printStackTrace();
}
if (sort != null && sort.toLowerCase().equals(DESC)) {
return -ret;
} else {
return ret;
}
}
});
return list;
}
/**
* 對list中的元素進行排序.
*
* @param list
* 排序集合
* @param field
* 排序字段
* @param sort
* 排序方式: SortList.DESC(降序) SortList.ASC(升序).
* @return
*/
@SuppressWarnings("unchecked")
public static List<?> sortMapList(List<?> list, final String field,
final String sort) {
Collections.sort(list, new Comparator() {
public int compare(Object a, Object b) {
int ret = 0;
try {
Map<String,Object> tempA = (Map<String,Object>)a;
Map<String,Object> tempB = (Map<String,Object>)b;
Object fA = tempA.get(field);
Object fB = tempB.get(field);
if(fA instanceof String){
fA = Double.parseDouble((String)fA);
}
if(fB instanceof String){
fB = Double.parseDouble((String)fB);
}
ret = ((Double)fA).compareTo((Double)fB);
}catch (Exception e) {
e.printStackTrace();
}
if (sort != null && sort.toLowerCase().equals(DESC)) {
return -ret;
} else {
return ret;
}
}
});
return list;
}
/**
* 對list中的元素按fields和sorts進行排序,
* fields[i]指定排序字段,sorts[i]指定排序方式.如果sorts[i]爲空則默認按升序排列.
*
* @param list
* @param fields
* @param sorts
* @return
*/
@SuppressWarnings("unchecked")
public static List<?> sort(List<?> list, String[] fields, String[] sorts) {
if (fields != null && fields.length > 0) {
for (int i = fields.length - 1; i >= 0; i--) {
final String field = fields[i];
String tmpSort = ASC;
if (sorts != null && sorts.length > i && sorts[i] != null) {
tmpSort = sorts[i];
}
final String sort = tmpSort;
Collections.sort(list, new Comparator() {
public int compare(Object a, Object b) {
int ret = 0;
try {
Field f = a.getClass().getDeclaredField(field);
f.setAccessible(true);
Class<?> type = f.getType();
if (type == int.class) {
ret = ((Integer) f.getInt(a))
.compareTo((Integer) f.getInt(b));
} else if (type == double.class) {
ret = ((Double) f.getDouble(a))
.compareTo((Double) f.getDouble(b));
} else if (type == long.class) {
ret = ((Long) f.getLong(a)).compareTo((Long) f
.getLong(b));
} else if (type == float.class) {
ret = ((Float) f.getFloat(a))
.compareTo((Float) f.getFloat(b));
} else if (type == Date.class) {
ret = ((Date) f.get(a)).compareTo((Date) f
.get(b));
} else if (isImplementsOf(type, Comparable.class)) {
ret = ((Comparable) f.get(a))
.compareTo((Comparable) f.get(b));
} else {
ret = String.valueOf(f.get(a)).compareTo(
String.valueOf(f.get(b)));
}
} catch (SecurityException e) {
e.printStackTrace();
} catch (NoSuchFieldException e) {
e.printStackTrace();
} catch (IllegalArgumentException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
}
if (sort != null && sort.toLowerCase().equals(DESC)) {
return -ret;
} else {
return ret;
}
}
});
}
}
return list;
}
/**
* 默認按正序排列
*
* @param list
* @param method
* @return
*/
public static List<?> sortByMethod(List<?> list, final String method) {
return sortByMethod(list, method, null);
}
@SuppressWarnings("unchecked")
public static List<?> sortByMethod(List<?> list, final String method,
final String sort) {
Collections.sort(list, new Comparator() {
public int compare(Object a, Object b) {
int ret = 0;
try {
Method m = a.getClass().getMethod(method, null);
m.setAccessible(true);
Class<?> type = m.getReturnType();
if (type == int.class) {
ret = ((Integer) m.invoke(a, null))
.compareTo((Integer) m.invoke(b, null));
} else if (type == double.class) {
ret = ((Double) m.invoke(a, null)).compareTo((Double) m
.invoke(b, null));
} else if (type == long.class) {
ret = ((Long) m.invoke(a, null)).compareTo((Long) m
.invoke(b, null));
} else if (type == float.class) {
ret = ((Float) m.invoke(a, null)).compareTo((Float) m
.invoke(b, null));
} else if (type == Date.class) {
ret = ((Date) m.invoke(a, null)).compareTo((Date) m
.invoke(b, null));
} else if (isImplementsOf(type, Comparable.class)) {
ret = ((Comparable) m.invoke(a, null))
.compareTo((Comparable) m.invoke(b, null));
} else {
ret = String.valueOf(m.invoke(a, null)).compareTo(
String.valueOf(m.invoke(b, null)));
}
if (isImplementsOf(type, Comparable.class)) {
ret = ((Comparable) m.invoke(a, null))
.compareTo((Comparable) m.invoke(b, null));
} else {
ret = String.valueOf(m.invoke(a, null)).compareTo(
String.valueOf(m.invoke(b, null)));
}
}catch (Exception it) {
System.out.println(it);
}
if (sort != null && sort.toLowerCase().equals(DESC)) {
return -ret;
} else {
return ret;
}
}
});
return list;
}
@SuppressWarnings("unchecked")
public static List<?> sortByMethod(List<?> list, final String methods[],
final String sorts[]) {
if (methods != null && methods.length > 0) {
for (int i = methods.length - 1; i >= 0; i--) {
final String method = methods[i];
String tmpSort = ASC;
if (sorts != null && sorts.length > i && sorts[i] != null) {
tmpSort = sorts[i];
}
final String sort = tmpSort;
Collections.sort(list, new Comparator() {
public int compare(Object a, Object b) {
int ret = 0;
try {
Method m = a.getClass().getMethod(method, null);
m.setAccessible(true);
Class<?> type = m.getReturnType();
if (type == int.class) {
ret = ((Integer) m.invoke(a, null))
.compareTo((Integer) m.invoke(b, null));
} else if (type == double.class) {
ret = ((Double) m.invoke(a, null))
.compareTo((Double) m.invoke(b, null));
} else if (type == long.class) {
ret = ((Long) m.invoke(a, null))
.compareTo((Long) m.invoke(b, null));
} else if (type == float.class) {
ret = ((Float) m.invoke(a, null))
.compareTo((Float) m.invoke(b, null));
} else if (type == Date.class) {
ret = ((Date) m.invoke(a, null))
.compareTo((Date) m.invoke(b, null));
} else if (isImplementsOf(type, Comparable.class)) {
ret = ((Comparable) m.invoke(a, null))
.compareTo((Comparable) m.invoke(b,
null));
} else {
ret = String.valueOf(m.invoke(a, null))
.compareTo(
String.valueOf(m
.invoke(b, null)));
}
} catch (NoSuchMethodException ne) {
System.out.println(ne);
} catch (IllegalAccessException ie) {
System.out.println(ie);
} catch (InvocationTargetException it) {
System.out.println(it);
}
if (sort != null && sort.toLowerCase().equals(DESC)) {
return -ret;
} else {
return ret;
}
}
});
}
}
return list;
}
/**
* 判斷對象實現的所有接口中是否包含szInterface
*
* @param clazz
* @param szInterface
* @return
*/
public static boolean isImplementsOf(Class<?> clazz, Class<?> szInterface) {
boolean flag = false;
Class<?>[] face = clazz.getInterfaces();
for (Class<?> c : face) {
if (c == szInterface) {
flag = true;
} else {
flag = isImplementsOf(c, szInterface);
}
}
if (!flag && null != clazz.getSuperclass()) {
return isImplementsOf(clazz.getSuperclass(), szInterface);
}
return flag;
}
//根據MAP的值進行排序
public static Map<String, Object> sortMapByValue(Map<String, Object> oriMap) {
Map<String, Object> sortedMap = new LinkedHashMap<String, Object>();
if (oriMap != null && !oriMap.isEmpty()) {
List<Map.Entry<String, Object>> entryList = new ArrayList<Map.Entry<String, Object>>(oriMap.entrySet());
Collections.sort(entryList,
new Comparator<Map.Entry<String, Object>>() {
public int compare(Map.Entry<String, Object> entry1,
Map.Entry<String, Object> entry2) {
int value1 = 0, value2 = 0;
try {
value1 = getInt(entry1.getValue());
value2 = getInt(entry2.getValue());
} catch (NumberFormatException e) {
value1 = 0;
value2 = 0;
}
return value2 - value1;
}
});
Iterator<Map.Entry<String, Object>> iter = entryList.iterator();
Map.Entry<String, Object> tmpEntry = null;
while (iter.hasNext()) {
tmpEntry = iter.next();
sortedMap.put(tmpEntry.getKey(), tmpEntry.getValue());
}
}
return sortedMap;
}
private static int getInt(Object str) {
int i = 0;
try {
Pattern p = Pattern.compile("^\\d+");
Matcher m = p.matcher(str.toString());
if (m.find()) {
i = Integer.valueOf(m.group());
}
} catch (NumberFormatException e) {
e.printStackTrace();
}
return i;
}
}
