add 增加 StreamUtils 流工具 简化 stream 流操纵

ruoyi-common/src/main/java/com/ruoyi/common/utils/StreamUtils.java

@@ -0,0 +1,34 @@
+package com.ruoyi.common.utils;
+
+import cn.hutool.core.collection.CollStreamUtil;
+import cn.hutool.core.collection.CollUtil;
+
+import java.util.*;
+import java.util.function.Function;
+import java.util.function.Predicate;
+import java.util.stream.Collectors;
+
+public class StreamUtils extends CollStreamUtil {
+
+    public static <E> List<E> filter(Collection<E> collection, Predicate<E> function) {
+        if (CollUtil.isEmpty(collection)) {
+            return Collections.emptyList();
+        }
+        return collection.stream().filter(function).collect(Collectors.toList());
+    }
+
+    public static <E> String join(Collection<E> collection,  Function<E, String> function) {
+        return join(collection, function, ",");
+    }
+
+    public static <E> String join(Collection<E> collection,  Function<E, String> function, CharSequence delimiter) {
+        if (CollUtil.isEmpty(collection)) {
+            return StringUtils.EMPTY;
+        }
+        return collection.stream().map(function).filter(Objects::nonNull).collect(Collectors.joining(delimiter));
+    }
+
+    public static <E> List<E> sorted(Collection<E> collection, Comparator<E> comparing) {
+        return collection.stream().sorted(comparing).collect(Collectors.toList());
+    }
+}