105 lines
2.9 KiB
Java
105 lines
2.9 KiB
Java
package net.tccn.base;
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import java.lang.reflect.Array;
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import java.util.*;
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import java.util.stream.Collectors;
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import java.util.stream.Stream;
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/**
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* Created by liangxianyou at 2019/3/19 18:01.
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*/
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public class Utils {
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/**
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* 将集合数组合并到一个Set<T> 集合中
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* @param <T> 泛型
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* @param streams 集合数组
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* @return
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*/
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public static <T> Stream<T> concat(Stream<T> ... streams) {
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Stream<T> stream = Stream.empty();
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for (int i = 0; i < streams.length; i++) {
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stream = Stream.concat(stream, streams[i]);
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}
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return stream;
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}
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/**
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* 将字符串第一个字母转大写
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* @param str 待转换字符串
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* @return
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*/
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public static String toUpperCaseFirst(String str) {
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Objects.requireNonNull(str);
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return str.substring(0, 1).toUpperCase() + str.substring(1);
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}
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/**
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* 转化集合为数组，带泛型支持
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* @param values 集合
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* @param <T> 泛型
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* @return
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*/
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public static <T> T[] toArray(Collection<T> values) {
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if (values == null || values.size() == 0)
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throw new UnsupportedOperationException("Not supported yet.");
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Class<?> clazz = null;
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for (T entity : values) {
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clazz = entity.getClass();
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break;
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}
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return values.toArray((T[]) Array.newInstance(clazz, values.size()));
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}
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/**
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* 转化集合为数组，带泛型支持
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* @param values 集合
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* @param <T> 泛型
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* @return
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*/
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public static <T> T[] toArray(Stream<T> values) {
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if (values == null || values.count() == 0)
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throw new UnsupportedOperationException("Not supported yet.");
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List<T> list = values.collect(Collectors.toList());
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return toArray(list);
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}
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/**
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*
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* @param type 待加载的class 类型
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* @param name class 的实现名称
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* @param <T> 泛型<T>
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* @return
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*/
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public static <T extends IService> T getDbSource(Class<T> type, String name) {
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ServiceLoader<T> loader = ServiceLoader.load(type);
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Iterator<T> iterator = loader.iterator();
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if (iterator.hasNext()) {
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T t = iterator.next();
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if (name.equalsIgnoreCase(t.getType())) {
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return t;
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}
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}
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return null;
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}
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public static boolean isEmpty(Object obj) {
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if (obj == null)
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return true;
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if (obj instanceof List)
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return ((List) obj).isEmpty();
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if (obj instanceof String)
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return ((String) obj).isEmpty();
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if (obj instanceof Map)
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return ((Map) obj).isEmpty();
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if (obj instanceof Collection)
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return ((Collection) obj).isEmpty();
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if (obj instanceof Object[])
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return ((Object[]) obj).length == 0;
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return false;
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}
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}
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