fix test

hutool-json/src/main/java/cn/hutool/json/JSONObject.java

@@ -420,7 +420,7 @@ public class JSONObject implements JSON, JSONGetter<String>, Map<String, Object>
 	}
 
 	/**
-	 * 积累值。类似于put，当key对应value已经存在时，与value组成新的JSONArray. <br>
+	 * 积累值。类似于set，当key对应value已经存在时，与value组成新的JSONArray. <br>
 	 * 如果只有一个值，此值就是value，如果多个值，则是添加到新的JSONArray中
 	 *
 	 * @param key   键
@@ -432,11 +432,11 @@ public class JSONObject implements JSON, JSONGetter<String>, Map<String, Object>
 		InternalJSONUtil.testValidity(value);
 		Object object = this.getObj(key);
 		if (object == null) {
-			this.set(key, (value instanceof JSONArray) ? value : new JSONArray(this.config).set(value));
+			this.set(key, value);
 		} else if (object instanceof JSONArray) {
 			((JSONArray) object).set(value);
 		} else {
-			this.set(key, new JSONArray(this.config).set(object).set(value));
+			this.set(key, JSONUtil.createArray(this.config).set(object).set(value));
 		}
 		return this;
 	}

hutool-json/src/test/java/cn/hutool/json/JSONObjectTest.java

@@ -538,7 +538,13 @@ public class JSONObjectTest {
 
 	@Test
 	public void accumulateTest(){
-		final JSONObject accumulate = JSONUtil.createObj().accumulate("key1", "value1");
-		Assert.assertEquals("{\"key1\":[\"value1\"]}", accumulate.toString());
+		final JSONObject jsonObject = JSONUtil.createObj().accumulate("key1", "value1");
+		Assert.assertEquals("{\"key1\":\"value1\"}", jsonObject.toString());
+
+		jsonObject.accumulate("key1", "value2");
+		Assert.assertEquals("{\"key1\":[\"value1\",\"value2\"]}", jsonObject.toString());
+
+		jsonObject.accumulate("key1", "value3");
+		Assert.assertEquals("{\"key1\":[\"value1\",\"value2\",\"value3\"]}", jsonObject.toString());
 	}
 }