Change HashMap to LinkedHashMap in ResultItems for same order of input and output #76

webmagic-core/src/main/java/us/codecraft/webmagic/ResultItems.java

 package us.codecraft.webmagic;
 
 import java.util.HashMap;
+import java.util.LinkedHashMap;
 import java.util.Map;
 
 /**
@@ -14,7 +15,7 @@ import java.util.Map;
  */
 public class ResultItems {
 
-    private Map<String, Object> fields = new HashMap<String, Object>();
+    private Map<String, Object> fields = new LinkedHashMap<String, Object>();
 
     private Request request;
 

webmagic-core/src/test/java/us/codecraft/webmagic/ResultItemsTest.java

+package us.codecraft.webmagic;
+
+import org.junit.Test;
+
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * @author code4crafter@gmail.com
+ */
+public class ResultItemsTest {
+
+    @Test
+    public void testOrderOfEntries() throws Exception {
+        ResultItems resultItems = new ResultItems();
+        resultItems.put("a", "a");
+        resultItems.put("b", "b");
+        resultItems.put("c", "c");
+        assertThat(resultItems.getAll().keySet()).containsExactly("a","b","c");
+
+    }
+}