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src/main/java/net/tccn/base/Utils.java

@@ -0,0 +1,104 @@
+package net.tccn.base;
+
+import java.lang.reflect.Array;
+import java.util.*;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+/**
+ * Created by liangxianyou at 2019/3/19 18:01.
+ */
+public class Utils {
+
+    /**
+     * 将集合数组合并到一个Set<T> 集合中
+     * @param <T>     泛型
+     * @param streams 集合数组
+     * @return
+     */
+    public static <T> Stream<T> concat(Stream<T> ... streams) {
+        Stream<T> stream = Stream.empty();
+        for (int i = 0; i < streams.length; i++) {
+            stream = Stream.concat(stream, streams[i]);
+        }
+        return stream;
+    }
+
+    /**
+     * 将字符串第一个字母转大写
+     * @param str 待转换字符串
+     * @return
+     */
+    public static String toUpperCaseFirst(String str) {
+        Objects.requireNonNull(str);
+        return str.substring(0, 1).toUpperCase() + str.substring(1);
+    }
+
+    /**
+     * 转化集合为数组，带泛型支持
+     * @param values 集合
+     * @param <T>    泛型
+     * @return
+     */
+    public static <T> T[] toArray(Collection<T> values) {
+        if (values == null || values.size() == 0)
+            throw new UnsupportedOperationException("Not supported yet.");
+        Class<?> clazz = null;
+        for (T entity : values) {
+            clazz = entity.getClass();
+            break;
+        }
+        return values.toArray((T[]) Array.newInstance(clazz, values.size()));
+    }
+
+    /**
+     * 转化集合为数组，带泛型支持
+     * @param values 集合
+     * @param <T>    泛型
+     * @return
+     */
+    public static <T> T[] toArray(Stream<T> values) {
+        if (values == null || values.count() == 0)
+            throw new UnsupportedOperationException("Not supported yet.");
+
+        List<T> list = values.collect(Collectors.toList());
+        return toArray(list);
+    }
+
+    /**
+     *
+     * @param type 待加载的class 类型
+     * @param name class 的实现名称
+     * @param <T> 泛型<T>
+     * @return
+     */
+    public static <T extends IService> T getDbSource(Class<T> type, String name) {
+        ServiceLoader<T> loader = ServiceLoader.load(type);
+        Iterator<T> iterator = loader.iterator();
+
+        if (iterator.hasNext()) {
+            T t = iterator.next();
+            if (name.equalsIgnoreCase(t.getType())) {
+                return t;
+            }
+        }
+        return null;
+    }
+
+    public static boolean isEmpty(Object obj) {
+        if (obj == null)
+            return true;
+        if (obj instanceof List)
+            return ((List) obj).isEmpty();
+        if (obj instanceof String)
+            return ((String) obj).isEmpty();
+        if (obj instanceof Map)
+            return ((Map) obj).isEmpty();
+        if (obj instanceof Collection)
+            return ((Collection) obj).isEmpty();
+        if (obj instanceof Object[])
+            return ((Object[]) obj).length == 0;
+        return false;
+    }
+
+}