io.leopard.burrow.util.ListUtil Maven / Gradle / Ivy
package io.leopard.burrow.util;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Set;
import org.apache.commons.lang.StringUtils;
/**
* List转换工具类
*
* @author Administrator
*
*/
public class ListUtil {
/**
* 返回list的size,如果list等于null，返回0
*
* @param list
* @return
*/
public static int size(Object[] list) {
if (list == null) {
return 0;
}
else {
return list.length;
}
}
/**
* 返回list的size,如果list等于null，返回0
*
* @param list
* @return
*/
public static int size(long[] list) {
if (list == null) {
return 0;
}
else {
return list.length;
}
}
/**
* 返回list的size,如果list等于null，返回0
*
* @param list
* @return
*/
public static int size(List list) {
if (list == null) {
return 0;
}
else {
return list.size();
}
}
/**
* List的内容去重
*
* @param list
* 需要去重的list
* @return 去重后的list
*/
public static List uniq(List list) {
if (list == null) {
return null;
}
List result = new ArrayList();
for (String str : list) {
if (!result.contains(str)) {
result.add(str);
}
}
return result;
}
/**
* 判断List是否为非空
*
* @param list
* List
* @return 若非空返回true
*/
public static boolean isNotEmpty(List list) {
return !isEmpty(list);
// if (list == null || list.isEmpty()) {
// return false;
// }
// else {
// return true;
// }
}
/**
* 判断List是否为空
*
* @param list
* List
* @return 若空返回true
*/
public static boolean isEmpty(List list) {
if (list == null || list.isEmpty()) {
return true;
}
else {
return false;
}
}
/**
* 把null或者不包含元素的List转成null
*
* @param list
* List对象
* @return 转换后的List对象
*/
public static List toStringResult(List list) {
if (list == null || list.isEmpty()) {
return null;
}
return list;
}
/**
* 把null转换成长度为0的数组
*
* @param strs
* 字符串数组
* @return 转换后的数组
*/
public static String[] defaultStrings(String[] strs) {
if (strs == null) {
return new String[0];
}
return strs;
}
/**
* 把null转成包含0个元素的List
*
* @param list
* List对象
* @return 转换后的List
*/
public static List defaultList(List list) {
if (list == null) {
return new ArrayList();
}
return list;
}
/**
* 去除List中的null元素
*
* @param list
* List
* @return 去除null元素后的List
*/
public static List noNull(List list) {
if (isEmpty(list)) {
return null;
}
// 删除空记录
Iterator iterator = list.iterator();
while (iterator.hasNext()) {
Object next = iterator.next();
if (next == null) {
iterator.remove();
}
}
return list;
}
/**
* 将字符串集合转成字符串List
*
* @param set
* 字符串集合
* @return 转换后的List
*/
public static List toList(Set set) {
if (SetUtil.isEmpty(set)) {
return null;
}
List list = new ArrayList();
for (String str : set) {
list.add(str);
}
return list;
}
// public static Set toSet(List list) {
// if (list == null || list.isEmpty()) {
// return null;
// }
// Set set = new LinkedHashSet();
// for (String element : list) {
// set.add(element);
// }
// return set;
// }
/**
* 将List转成Set
*
* @param list
* List
* @return Set
*/
public static Set toSet(List list) {
if (isEmpty(list)) {
return null;
}
Set set = new LinkedHashSet();
for (KEYTYPE element : list) {
set.add(element);
}
return set;
}
/**
* 将整型List转成整形Set
*
* @param list
* List
* @return Set
*/
public static Set toIntSet(List list) {
if (isEmpty(list)) {
return null;
}
Set set = new LinkedHashSet();
for (Integer element : list) {
set.add(element);
}
return set;
}
/**
* 将整数添加到一个新的List
*
* @param num
* 整数
* @return 新的List
*/
public static List toIntList(int num) {
List list = new ArrayList();
list.add(num);
return list;
}
/**
* 将多个整数(用“,”隔开)添加到一个新的整型List
*
* @param content
* 包含多个整数的字符串
* @return 整型List
*/
public static List toIntList(String content) {
if (StringUtils.isEmpty(content)) {
return null;
}
String[] strs = StringUtils.split(content, ",");
List list = new ArrayList();
for (String str : strs) {
int num = Integer.parseInt(str.trim());
list.add(num);
}
return list;
}
/**
* 将文本内容(用“,”隔开)添加到一个新的字符串List
*
* @param content
* 文本
* @return 字符串List
*/
public static List toList(String content) {
if (StringUtils.isEmpty(content)) {
return null;
}
String[] strs = StringUtils.split(content, ",");
List list = new ArrayList();
for (String str : strs) {
list.add(str);
}
return list;
}
/**
* 将文本内容(用“,”隔开)添加到一个新的字符串List
*
* @param content
* 文本
* @param trim
* 忽略头尾空白
* @return 字符串List
*/
public static List toList(String content, boolean trim) {
if (StringUtils.isEmpty(content)) {
return null;
}
if (!trim) {
return toList(content);
}
content = content.trim();
String[] strs = StringUtils.split(content, ",");
List list = new ArrayList();
for (String str : strs) {
str = str.trim();
list.add(str);
}
return list;
}
/**
* 字符串集合转成整型List
*
* @param members
* 集合
* @return 转换后的整型List
*/
public static List toIntList(Set members) {
if (SetUtil.isEmpty(members)) {
return null;
}
List result = new ArrayList();
Iterator iterator = members.iterator();
while (iterator.hasNext()) {
String str = iterator.next();
Integer newsId = Integer.parseInt(str);
result.add(newsId);
}
return result;
}
/**
* 对整型集合中的元素添加前缀，保存到字符串数组并返回该数组
*
* @param prefix
* 前缀
* @param idSet
* 整型集合
* @return 转换后的字符串数组
*/
public static String[] getIntKeys(String prefix, Set idSet) {
String[] keys = new String[idSet.size()];
int index = 0;
for (Integer id : idSet) {
keys[index] = prefix + ":" + id;
index++;
}
return keys;
}
/**
* 对字符串集合中的元素添加前缀，保存到数组并返回该数组
*
* @param prefix
* 前缀
* @param usernameSet
* 字符串集合
* @return 转换后的字符串数组
*/
public static String[] getKeys(String prefix, Set usernameSet) {
String[] keys = new String[usernameSet.size()];
int index = 0;
for (String username : usernameSet) {
keys[index] = prefix + ":" + username;
index++;
}
return keys;
}
/**
* 整型数组转成字符串数组
*
* @param nums
* 整型数组
* @return 字符串数组
*/
public static String[] toStringArray(int[] nums) {
if (nums == null) {
return null;
}
String[] fields = new String[nums.length];
int index = 0;
for (Integer num : nums) {
fields[index] = Integer.toString(num);
index++;
}
return fields;
}
/**
* 整型List转成字符串数组
*
* @param list
* 整型List
* @return 字符串数组
*/
public static String[] toStringArray(List list) {
if (isEmpty(list)) {
return null;
}
String[] fields = new String[list.size()];
int index = 0;
for (Integer num : list) {
fields[index] = Integer.toString(num);
index++;
}
return fields;
}
/**
* 字符串List转成字符串数组
*
* @param list
* 字符串List
* @return 字符串数组
*/
public static String[] toArray(List list) {
if (isEmpty(list)) {
return null;
}
String[] fields = new String[list.size()];
int index = 0;
for (String str : list) {
fields[index] = str;
index++;
}
return fields;
}
/**
* 字符串List转成整型List，可包含null元素
*
* @param members
* 字符串List
* @return 整型List
*/
public static List toIntList(List members) {
if (isEmpty(members)) {
return null;
}
List result = new ArrayList();
Iterator iterator = members.iterator();
while (iterator.hasNext()) {
String str = iterator.next();
if (str == null) {
result.add(null);
}
else {
int member = Integer.parseInt(str);
result.add(member);
}
}
return result;
}
/**
* 字符串List转成整型List，可包含null元素
*
* @param members
* 字符串List
* @return 整型List
*/
public static List toLongList(List members) {
if (isEmpty(members)) {
return null;
}
List result = new ArrayList();
Iterator iterator = members.iterator();
while (iterator.hasNext()) {
String str = iterator.next();
if (str == null) {
result.add(null);
}
else {
long member = Long.parseLong(str);
result.add(member);
}
}
return result;
}
/**
* 生成包含指定前缀，从指定起始编号开始，大小为指定长度的字符串List
*
* @param prefix
* 前缀
* @param start
* 起始编号
* @param size
* 长度
* @return 字符串List
*/
public static List makeList(String prefix, int start, int size) {
List list = new ArrayList();
int end = start + size;
for (int i = start; i < end; i++) {
list.add(prefix + i);
}
return list;
}
/**
* 将文本(用“,”隔开)转换成长整型List
*
* @param content
* 文本
* @return 长整型List
*/
public static List makeLongList(String content) {
String[] strs = StringUtils.split(content, ",");
List list = new ArrayList();
for (String str : strs) {
str = str.trim();
long num = Long.parseLong(str);
list.add(num);
}
return list;
}
public static List makeLongList(String content, String splitRegex) {
String[] strs = content.split(splitRegex);
List list = new ArrayList();
for (String str : strs) {
str = str.trim();
long num = Long.parseLong(str);
list.add(num);
}
return list;
}
/**
* 将文本(用“,”隔开)转换成整型List
*
* @param content
* 文本
* @return 整型List
*/
public static List makeIntList(String content) {
String[] strs = StringUtils.split(content, ",");
List list = new ArrayList();
for (String str : strs) {
str = str.trim();
int num = Integer.parseInt(str);
list.add(num);
}
return list;
}
/**
* 将文本(用“,”隔开)转换成Double List
*
* @param content
* 文本
* @return 整型List
*/
public static List makeDoubleList(String content) {
String[] strs = StringUtils.split(content, ",");
List list = new ArrayList();
for (String str : strs) {
str = str.trim();
double num = Double.parseDouble(str);
list.add(num);
}
return list;
}
public static List makeDoubleList(double... nums) {
List list = new ArrayList();
for (double num : nums) {
list.add(num);
}
return list;
}
/**
* 将文本(用“,”隔开)转换成字符串List
*
* @param content
* 文本
* @return 字符串List
*/
public static List makeList(String content) {
String[] strs = StringUtils.split(content, ",");
List list = new ArrayList();
for (String str : strs) {
str = str.trim();
list.add(str);
}
return list;
}
/**
* 将整型List转换成字符串List
*
* @param numList
* 整型List
* @return 字符串List
*/
public static List toStringList(List numList) {
List strList = new ArrayList();
for (Integer num : numList) {
strList.add(Integer.toString(num));
}
return strList;
}
public static List sub(List list, int start, int max) {
if (ListUtil.isEmpty(list)) {
return list;
}
List newList = new ArrayList();
int count = 0;
for (int i = 0; i < list.size(); i++) {
if (i < start) {
continue;
}
T element = list.get(i);
newList.add(element);
count++;
if (count >= max) {
break;
}
}
return newList;
}
public static List sub(List list, int max) {
if (ListUtil.isEmpty(list)) {
return list;
}
List newList = new ArrayList();
int count = 0;
for (T element : list) {
newList.add(element);
count++;
if (count >= max) {
break;
}
}
return newList;
}
public static List removeAll(Collection collection, Collection remove) {
List list = new ArrayList();
for (Iterator iter = collection.iterator(); iter.hasNext();) {
T obj = iter.next();
if (remove.contains(obj) == false) {
list.add(obj);
}
}
return list;
}
}
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