Merge pull request #3449 from pymBupt/issue/#3448

fix issue 3448

src/main/java/com/alibaba/fastjson/TypeReference.java

@@ -122,7 +122,7 @@ private Type handlerParameterizedType(ParameterizedType type, Type[] actualTypeA
 
             // 如果有多层泛型且该泛型已经注明实现的情况下，判断该泛型下一层是否还有泛型
             if(argTypes[i] instanceof ParameterizedType) {
-                return handlerParameterizedType((ParameterizedType) argTypes[i], actualTypeArguments, actualIndex);
+                argTypes[i] = handlerParameterizedType((ParameterizedType) argTypes[i], actualTypeArguments, actualIndex);
             }
         }
 

src/test/java/com/alibaba/json/bvt/issue_3300/Issue3448.java

@@ -0,0 +1,43 @@
+package com.alibaba.json.bvt.issue_3300;
+
+import java.lang.reflect.ParameterizedType;
+import java.lang.reflect.Type;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+
+import com.alibaba.fastjson.JSON;
+import com.alibaba.fastjson.TypeReference;
+
+import junit.framework.TestCase;
+import org.junit.Test;
+
+/**
+ * @author yumin.pym
+ */
+public class Issue3448 extends TestCase {
+    public static class SelfTypeReference<T> {
+
+    }
+
+    @Test
+    public void test() {
+        List<Map<String, List<String>>> list = new ArrayList<>(4);
+        list.add(Collections.singletonMap("key1", Collections.singletonList("item")));
+        String text = JSON.toJSONString(list);
+        System.out.println("text = " + text);
+
+        List<Map<String, List<String>>> result = parseObject(text,
+            new SelfTypeReference<Map<String, List<String>>>() {});
+        System.out.println("result = " + result);
+        TestCase.assertTrue(result.get(0) instanceof Map);
+        TestCase.assertTrue(result.get(0).get("key1").get(0) instanceof String);
+    }
+
+    public <T> List<T> parseObject(String text, SelfTypeReference<T> selfTypeReference) {
+        Type genericSuperclass = selfTypeReference.getClass().getGenericSuperclass();
+        Type[] actualTypeArguments = ((ParameterizedType)genericSuperclass).getActualTypeArguments();
+        return JSON.parseObject(text, new TypeReference<List<T>>(actualTypeArguments) {});
+    }
+}