improved fluent setter method support

src/main/java/com/alibaba/fastjson/parser/JavaBeanInfo.java

@@ -377,7 +377,7 @@ class JavaBeanInfo {
                 // support builder set
 
                 Class<?> returnType = method.getReturnType();
-                if ((!(returnType == Void.TYPE || returnType == clazz)) //
+                if ((!(returnType == Void.TYPE || returnType == method.getDeclaringClass())) //
                         || method.getParameterTypes().length != 1 //
                         || method.getDeclaringClass() == Object.class //
                         ) {

src/test/java/com/alibaba/json/bvt/FluentSetterTest.java

@@ -0,0 +1,52 @@
+package com.alibaba.json.bvt;
+
+import org.junit.Assert;
+
+import com.alibaba.fastjson.JSON;
+
+import junit.framework.TestCase;
+
+public class FluentSetterTest extends TestCase {
+
+    public void test_fluent() throws Exception {
+        B b = new B();
+        b.setId(1001);
+        b.setValue(1002);
+        
+        String text = JSON.toJSONString(b);
+        Assert.assertEquals("{\"id\":1001,\"value\":1002}", text);
+        
+        B b1 = JSON.parseObject(text, B.class);
+        Assert.assertEquals(b.getId(), b1.getId());
+        Assert.assertEquals(b.getValue(), b1.getValue());
+    }
+
+    public static class A {
+
+        private int id;
+
+        public int getId() {
+            return id;
+        }
+
+        public A setId(int id) {
+            this.id = id;
+            return this;
+        }
+    }
+
+    public static class B extends A {
+
+        private int value;
+
+        public int getValue() {
+            return value;
+        }
+
+        public B setValue(int value) {
+            this.value = value;
+            return this;
+        }
+
+    }
+}