diff --git a/core/src/main/java/com/alibaba/fastjson2/writer/ObjectWriterCreatorASM.java b/core/src/main/java/com/alibaba/fastjson2/writer/ObjectWriterCreatorASM.java
index ab8f7b0483..fce84bc1ac 100644
--- a/core/src/main/java/com/alibaba/fastjson2/writer/ObjectWriterCreatorASM.java
+++ b/core/src/main/java/com/alibaba/fastjson2/writer/ObjectWriterCreatorASM.java
@@ -2385,7 +2385,7 @@ private void gwInt32(
             int OBJECT,
             int i
     ) {
-        boolean jsonb = mwc.jsonb;
+//        boolean jsonb = mwc.jsonb;
         String classNameType = mwc.classNameType;
         MethodWriter mw = mwc.mw;
         Class<?> fieldClass = fieldWriter.fieldClass;
@@ -2463,7 +2463,7 @@ private void gwInt64(
             int OBJECT,
             int i
     ) {
-        boolean jsonb = mwc.jsonb;
+//        boolean jsonb = mwc.jsonb;
         MethodWriter mw = mwc.mw;
         Class<?> fieldClass = fieldWriter.fieldClass;
         String classNameType = mwc.classNameType;
@@ -2473,20 +2473,16 @@ private void gwInt64(
         Label endIfNull_ = new Label(), notNull_ = new Label(), writeNullValue_ = new Label();
 
         genGetObject(mwc, fieldWriter, i, OBJECT);
+        mw.visitInsn(Opcodes.DUP);
+        mw.visitVarInsn(Opcodes.ASTORE, FIELD_VALUE);
+        mw.visitJumpInsn(Opcodes.IFNONNULL, notNull_);
 
         if ((fieldWriter.features & WriteNulls.mask) == 0) {
-            mw.visitInsn(Opcodes.DUP);
-            mw.visitVarInsn(Opcodes.ASTORE, FIELD_VALUE);
-
-            mw.visitJumpInsn(Opcodes.IFNONNULL, notNull_);
-
             mwc.genIsEnabled(
                     WriteNulls.mask | NullAsDefaultValue.mask | WriteNullNumberAsZero.mask,
                     writeNullValue_,
                     endIfNull_
             );
-        } else {
-            mw.visitVarInsn(Opcodes.ASTORE, FIELD_VALUE);
         }
 
         mw.visitLabel(writeNullValue_);
@@ -2539,19 +2535,15 @@ private void gwDouble(
         Label endIfNull_ = new Label(), notNull_ = new Label(), writeNullValue_ = new Label();
 
         genGetObject(mwc, fieldWriter, i, OBJECT);
-
+        mw.visitInsn(Opcodes.DUP);
+        mw.visitVarInsn(Opcodes.ASTORE, FIELD_VALUE);
+        mw.visitJumpInsn(Opcodes.IFNONNULL, notNull_);
         if ((fieldWriter.features & WriteNulls.mask) == 0) {
-            mw.visitInsn(Opcodes.DUP);
-            mw.visitVarInsn(Opcodes.ASTORE, FIELD_VALUE);
-            mw.visitJumpInsn(Opcodes.IFNONNULL, notNull_);
-
             mwc.genIsEnabled(
                     WriteNulls.mask | NullAsDefaultValue.mask | WriteNullNumberAsZero.mask,
                     writeNullValue_,
                     endIfNull_
             );
-        } else {
-            mw.visitVarInsn(Opcodes.ASTORE, FIELD_VALUE);
         }
 
         mw.visitLabel(writeNullValue_);
diff --git a/core/src/test/java/com/alibaba/fastjson2/issues_3000/issue3049/DoubleClazz.java b/core/src/test/java/com/alibaba/fastjson2/issues_3000/issue3049/DoubleClazz.java
new file mode 100644
index 0000000000..7c57a00677
--- /dev/null
+++ b/core/src/test/java/com/alibaba/fastjson2/issues_3000/issue3049/DoubleClazz.java
@@ -0,0 +1,13 @@
+package com.alibaba.fastjson2.issues_3000.issue3049;
+
+import com.alibaba.fastjson2.JSONWriter;
+import com.alibaba.fastjson2.annotation.JSONField;
+import lombok.Getter;
+import lombok.Setter;
+
+@Getter
+@Setter
+public class DoubleClazz {
+    @JSONField(serializeFeatures = JSONWriter.Feature.WriteNulls)
+    private Double d;
+}
diff --git a/core/src/test/java/com/alibaba/fastjson2/issues_3000/issue3049/DoubleClazz2.java b/core/src/test/java/com/alibaba/fastjson2/issues_3000/issue3049/DoubleClazz2.java
new file mode 100644
index 0000000000..233e088de9
--- /dev/null
+++ b/core/src/test/java/com/alibaba/fastjson2/issues_3000/issue3049/DoubleClazz2.java
@@ -0,0 +1,10 @@
+package com.alibaba.fastjson2.issues_3000.issue3049;
+
+import lombok.Getter;
+import lombok.Setter;
+
+@Getter
+@Setter
+public class DoubleClazz2 {
+    private Double d;
+}
diff --git a/core/src/test/java/com/alibaba/fastjson2/issues_3000/issue3049/Issue3049.java b/core/src/test/java/com/alibaba/fastjson2/issues_3000/issue3049/Issue3049.java
new file mode 100644
index 0000000000..74de34d0a5
--- /dev/null
+++ b/core/src/test/java/com/alibaba/fastjson2/issues_3000/issue3049/Issue3049.java
@@ -0,0 +1,44 @@
+package com.alibaba.fastjson2.issues_3000.issue3049;
+
+import com.alibaba.fastjson2.JSON;
+import lombok.SneakyThrows;
+import org.junit.jupiter.api.Test;
+import org.skyscreamer.jsonassert.JSONAssert;
+
+/**
+ * @author 张治保
+ * @since 2024/10/8
+ */
+public class Issue3049 {
+    @Test
+    @SneakyThrows
+    void testDouble() {
+        DoubleClazz c = new DoubleClazz();
+        c.setD(1D);
+        JSONAssert.assertEquals("{\"d\":1.0}", JSON.toJSONString(c), true);
+        c.setD(null);
+        JSONAssert.assertEquals("{\"d\":null}", JSON.toJSONString(c), true);
+
+        DoubleClazz2 c2 = new DoubleClazz2();
+        c2.setD(1D);
+        JSONAssert.assertEquals("{\"d\":1.0}", JSON.toJSONString(c2), true);
+        c2.setD(null);
+        JSONAssert.assertEquals("{}", JSON.toJSONString(c2), true);
+    }
+
+    @Test
+    @SneakyThrows
+    void testLong() {
+        LongClazz c = new LongClazz();
+        c.setD(1L);
+        JSONAssert.assertEquals("{\"d\":1.0}", JSON.toJSONString(c), true);
+        c.setD(null);
+        JSONAssert.assertEquals("{\"d\":null}", JSON.toJSONString(c), true);
+
+        LongClazz2 c2 = new LongClazz2();
+        c2.setD(1L);
+        JSONAssert.assertEquals("{\"d\":1.0}", JSON.toJSONString(c2), true);
+        c2.setD(null);
+        JSONAssert.assertEquals("{}", JSON.toJSONString(c2), true);
+    }
+}
diff --git a/core/src/test/java/com/alibaba/fastjson2/issues_3000/issue3049/LongClazz.java b/core/src/test/java/com/alibaba/fastjson2/issues_3000/issue3049/LongClazz.java
new file mode 100644
index 0000000000..5cc9f5f3ee
--- /dev/null
+++ b/core/src/test/java/com/alibaba/fastjson2/issues_3000/issue3049/LongClazz.java
@@ -0,0 +1,13 @@
+package com.alibaba.fastjson2.issues_3000.issue3049;
+
+import com.alibaba.fastjson2.JSONWriter;
+import com.alibaba.fastjson2.annotation.JSONField;
+import lombok.Getter;
+import lombok.Setter;
+
+@Getter
+@Setter
+public class LongClazz {
+    @JSONField(serializeFeatures = JSONWriter.Feature.WriteNulls)
+    private Long d;
+}
diff --git a/core/src/test/java/com/alibaba/fastjson2/issues_3000/issue3049/LongClazz2.java b/core/src/test/java/com/alibaba/fastjson2/issues_3000/issue3049/LongClazz2.java
new file mode 100644
index 0000000000..eaeeebb0cd
--- /dev/null
+++ b/core/src/test/java/com/alibaba/fastjson2/issues_3000/issue3049/LongClazz2.java
@@ -0,0 +1,10 @@
+package com.alibaba.fastjson2.issues_3000.issue3049;
+
+import lombok.Getter;
+import lombok.Setter;
+
+@Getter
+@Setter
+public class LongClazz2 {
+    private Long d;
+}