diff --git a/src/org/redkale/convert/EnMember.java b/src/org/redkale/convert/EnMember.java
index 2768ec71b..f6f295522 100644
--- a/src/org/redkale/convert/EnMember.java
+++ b/src/org/redkale/convert/EnMember.java
@@ -21,14 +21,14 @@ import org.redkale.util.Attribute;
 @SuppressWarnings("unchecked")
 public final class EnMember<W extends Writer, T, F> implements Comparable<EnMember<W, T, F>> {
 
-    private final Attribute<T, F> attribute;
+    final Attribute<T, F> attribute;
 
     final Encodeable<W, F> encoder;
 
-    private final boolean istring;
+    final boolean istring;
 
-    //private final boolean isnumber;
-    private final boolean isbool;
+    //final boolean isnumber;
+    final boolean isbool;
 
     public EnMember(Attribute<T, F> attribute, Encodeable<W, F> encoder) {
         this.attribute = attribute;
@@ -52,21 +52,6 @@ public final class EnMember<W extends Writer, T, F> implements Comparable<EnMemb
         return attribute.field().equals(name);
     }
 
-    public boolean write(final W out, final boolean comma, final T obj) {
-        F value = attribute.get(obj);
-        if (value == null) return comma;
-        if (out.tiny()) {
-            if (istring) {
-                if (((CharSequence) value).length() == 0) return comma;
-            } else if (isbool) {
-                if (!((Boolean) value)) return comma;
-            }
-        }
-        out.writeField(comma, attribute);
-        encoder.convertTo(out, value);
-        return true;
-    }
-
     @Override
     public final int compareTo(EnMember<W, T, F> o) {
         if (o == null) return 1;
diff --git a/src/org/redkale/convert/ObjectDecoder.java b/src/org/redkale/convert/ObjectDecoder.java
index 5ca3f4218..0fe9b0fa2 100644
--- a/src/org/redkale/convert/ObjectDecoder.java
+++ b/src/org/redkale/convert/ObjectDecoder.java
@@ -10,12 +10,13 @@ import java.lang.reflect.*;
 import java.util.Arrays;
 import java.util.HashSet;
 import java.util.Set;
-import java.util.concurrent.atomic.AtomicInteger;
 import org.redkale.util.*;
 
 /**
  *
- * <p> 详情见: http://www.redkale.org
+ * <p>
+ * 详情见: http://www.redkale.org
+ *
  * @author zhangjx
  * @param <R> Reader输入的子类
  * @param <T> 反解析的数据类型
@@ -164,9 +165,9 @@ public final class ObjectDecoder<R extends Reader, T> implements Decodeable<R, T
      */
     @Override
     public final T convertFrom(final R in) {
-        final String clazz = in.readClassName();
-        if (clazz != null && !clazz.isEmpty()) return (T) factory.loadDecoder(factory.getEntity(clazz)).convertFrom(in);
-        if (in.readObjectB() == Reader.SIGN_NULL) return null;
+        final String clazz = in.readObjectB(typeClass);
+        if (clazz == null) return null;
+        if (!clazz.isEmpty()) return (T) factory.loadDecoder(factory.getEntity(clazz)).convertFrom(in);
         if (!this.inited) {
             synchronized (lock) {
                 try {
@@ -178,16 +179,14 @@ public final class ObjectDecoder<R extends Reader, T> implements Decodeable<R, T
         }
         if (this.creatorConstructorMembers == null) {  //空构造函数
             final T result = this.creator.create();
-            final AtomicInteger index = new AtomicInteger();
             while (in.hasNext()) {
-                DeMember member = in.readField(index, members);
+                DeMember member = in.readFieldName(members);
                 in.skipBlank();
                 if (member == null) {
                     in.skipValue(); //跳过不存在的属性的值
                 } else {
                     member.read(in, result);
                 }
-                index.incrementAndGet();
             }
             in.readObjectE();
             return result;
@@ -195,10 +194,9 @@ public final class ObjectDecoder<R extends Reader, T> implements Decodeable<R, T
             final DeMember<R, T, ?>[] fields = this.creatorConstructorMembers;
             final Object[] constructorParams = new Object[fields.length];
             final Object[][] otherParams = new Object[this.members.length][2];
-            final AtomicInteger index = new AtomicInteger();
             int oc = 0;
             while (in.hasNext()) {
-                DeMember member = in.readField(index, members);
+                DeMember member = in.readFieldName(members);
                 in.skipBlank();
                 if (member == null) {
                     in.skipValue(); //跳过不存在的属性的值
@@ -214,7 +212,6 @@ public final class ObjectDecoder<R extends Reader, T> implements Decodeable<R, T
                     }
                     if (flag) otherParams[oc++] = new Object[]{member.attribute, val};
                 }
-                index.incrementAndGet();
             }
             in.readObjectE();
             final T result = this.creator.create(constructorParams);
diff --git a/src/org/redkale/convert/ObjectEncoder.java b/src/org/redkale/convert/ObjectEncoder.java
index 23830d972..935d17168 100644
--- a/src/org/redkale/convert/ObjectEncoder.java
+++ b/src/org/redkale/convert/ObjectEncoder.java
@@ -12,7 +12,9 @@ import org.redkale.util.*;
 
 /**
  *
- * <p> 详情见: http://www.redkale.org
+ * <p>
+ * 详情见: http://www.redkale.org
+ *
  * @author zhangjx
  * @param <W> Writer输出的子类
  * @param <T> 序列化的数据类型
@@ -102,8 +104,7 @@ public final class ObjectEncoder<W extends Writer, T> implements Encodeable<W, T
     @Override
     public final void convertTo(W out, T value) {
         if (value == null) {
-            out.wirteClassName(null);
-            out.writeNull();
+            out.writeObjectNull(null);
             return;
         }
         if (!this.inited) {
@@ -121,10 +122,9 @@ public final class ObjectEncoder<W extends Writer, T> implements Encodeable<W, T
             factory.loadEncoder(clz).convertTo(out, value);
             return;
         }
-        out.writeObjectB(members.length, value);
-        boolean comma = false;
+        out.writeObjectB(value);
         for (EnMember member : members) {
-            comma = member.write(out, comma, value);
+            out.writeObjectField(member, value);
         }
         out.writeObjectE(value);
     }
diff --git a/src/org/redkale/convert/Reader.java b/src/org/redkale/convert/Reader.java
index 2789fa845..4f9db92bb 100644
--- a/src/org/redkale/convert/Reader.java
+++ b/src/org/redkale/convert/Reader.java
@@ -5,8 +5,6 @@
  */
 package org.redkale.convert;
 
-import java.util.concurrent.atomic.AtomicInteger;
-
 /**
  *
  * <p>
@@ -14,7 +12,10 @@ import java.util.concurrent.atomic.AtomicInteger;
  *
  * @author zhangjx
  */
-public interface Reader {
+public abstract class Reader {
+
+    //当前对象字段名的游标
+    protected int fieldIndex;
 
     public static final short SIGN_NULL = -1;
 
@@ -25,141 +26,143 @@ public interface Reader {
      *
      * @return 是否还存在下个元素或字段
      */
-    public boolean hasNext();
+    public abstract boolean hasNext();
 
     /**
      * 跳过值(不包含值前面的字段)
      */
-    public void skipValue();
+    public abstract void skipValue();
 
     /**
      * /跳过字段与值之间的多余内容， json就是跳过:符, map跳过:
      */
-    public void skipBlank();
+    public abstract void skipBlank();
 
     /**
-     * 读取对象的开头 返回字段数
+     * 读取对象的类名， 返回 null 表示对象为null， 返回空字符串表示当前class与返回的class一致，返回非空字符串表示class是当前class的子类。
      *
      * @return 返回字段数
      */
-    public int readObjectB();
+    public String readObjectB(final Class clazz) {
+        this.fieldIndex = 0;
+        return null;
+    }
 
     /**
      * 读取对象的尾端
      *
      */
-    public void readObjectE();
+    public abstract void readObjectE();
 
     /**
      * 读取数组的开头并返回数组的长度
      *
      * @return 返回数组的长度
      */
-    public int readArrayB();
+    public abstract int readArrayB();
 
     /**
      * 读取数组的尾端
      *
      */
-    public void readArrayE();
+    public abstract void readArrayE();
 
     /**
      * 读取map的开头并返回map的size
      *
      * @return 返回map的size
      */
-    public int readMapB();
+    public abstract int readMapB();
 
     /**
      * 读取数组的尾端
      *
      */
-    public void readMapE();
+    public abstract void readMapE();
 
     /**
      * 根据字段读取字段对应的DeMember
      *
-     * @param index   当前members的游标位置
      * @param members DeMember的全量集合
      * @return 匹配的DeMember
      */
-    public DeMember readField(final AtomicInteger index, final DeMember[] members);
+    public abstract DeMember readFieldName(final DeMember[] members);
 
     /**
      * 读取一个boolean值
      *
      * @return boolean值
      */
-    public boolean readBoolean();
+    public abstract boolean readBoolean();
 
     /**
      * 读取一个byte值
      *
      * @return byte值
      */
-    public byte readByte();
+    public abstract byte readByte();
 
     /**
      * 读取一个char值
      *
      * @return char值
      */
-    public char readChar();
+    public abstract char readChar();
 
     /**
      * 读取一个short值
      *
      * @return short值
      */
-    public short readShort();
+    public abstract short readShort();
 
     /**
      * 读取一个int值
      *
      * @return int值
      */
-    public int readInt();
+    public abstract int readInt();
 
     /**
      * 读取一个long值
      *
      * @return long值
      */
-    public long readLong();
+    public abstract long readLong();
 
     /**
      * 读取一个float值
      *
      * @return float值
      */
-    public float readFloat();
+    public abstract float readFloat();
 
     /**
      * 读取一个double值
      *
      * @return double值
      */
-    public double readDouble();
+    public abstract double readDouble();
 
     /**
      * 读取无转义字符长度不超过255的字符串， 例如枚举值、字段名、类名字符串等
      *
      * @return String值
      */
-    public String readSmallString();
+    public abstract String readSmallString();
 
     /**
      * 读取反解析对象的类名
      *
      * @return 类名
      */
-    public String readClassName();
+    public abstract String readClassName();
 
     /**
      * 读取一个String值
      *
      * @return String值
      */
-    public String readString();
+    public abstract String readString();
 
 }
diff --git a/src/org/redkale/convert/Writer.java b/src/org/redkale/convert/Writer.java
index b271b8739..e0069b1fa 100644
--- a/src/org/redkale/convert/Writer.java
+++ b/src/org/redkale/convert/Writer.java
@@ -14,156 +14,191 @@ import org.redkale.util.Attribute;
  *
  * @author zhangjx
  */
-public interface Writer {
+public abstract class Writer {
+
+    //当前对象输出字段名之前是否需要分隔符， JSON字段间的分隔符为,逗号
+    protected boolean comma;
 
     /**
      * 当tiny=true时， 字符串为空、boolean为false的字段值都会被跳过， 不会输出。
      *
      * @return 是否简化
      */
-    public boolean tiny();
+    public abstract boolean tiny();
 
     /**
      * 输出null值
      */
-    public void writeNull();
+    public abstract void writeNull();
 
     /**
      * 写入类名
      *
      * @param clazz 类名
      */
-    public void wirteClassName(String clazz);
+    public abstract void wirteClassName(String clazz);
 
     /**
      * 输出一个对象前的操作
+     * 注： 覆盖此方法必须要先调用父方法 super.writeObjectB(obj);
      *
-     * @param fieldCount 字段个数
-     *
-     * @param obj        写入的对象
+     * @param obj 写入的对象
      */
-    public void writeObjectB(int fieldCount, Object obj);
+    public void writeObjectB(Object obj) {
+        this.comma = false;
+    }
+
+    /**
+     * 输出一个为null的对象
+     *
+     * @param clazz 对象的类名
+     */
+    public final void writeObjectNull(final Class clazz) {
+        wirteClassName(null);
+        writeNull();
+    }
+
+    /**
+     * 输出一个对象的某个字段
+     *
+     * @param member 字段
+     *
+     * @param obj    写入的对象
+     */
+    public final void writeObjectField(final EnMember member, Object obj) {
+        Object value = member.attribute.get(obj);
+        if (value == null) return;
+        if (tiny()) {
+            if (member.istring) {
+                if (((CharSequence) value).length() == 0) return;
+            } else if (member.isbool) {
+                if (!((Boolean) value)) return;
+            }
+        }
+        this.writeFieldName(member.attribute);
+        member.encoder.convertTo(this, value);
+        this.comma = true;
+    }
 
     /**
      * 输出一个对象后的操作
      *
      * @param obj 写入的对象
      */
-    public void writeObjectE(Object obj);
+    public abstract void writeObjectE(Object obj);
 
     /**
      * 输出一个数组前的操作
      *
      * @param size 数组长度
      */
-    public void writeArrayB(int size);
+    public abstract void writeArrayB(int size);
 
     /**
      * 输出数组元素间的间隔符
      *
      */
-    public void writeArrayMark();
+    public abstract void writeArrayMark();
 
     /**
      * 输出一个数组后的操作
      *
      */
-    public void writeArrayE();
+    public abstract void writeArrayE();
 
     /**
      * 输出一个Map前的操作
      *
      * @param size map大小
      */
-    public void writeMapB(int size);
+    public abstract void writeMapB(int size);
 
     /**
      * 输出一个Map中key与value间的间隔符
      *
      */
-    public void writeMapMark();
+    public abstract void writeMapMark();
 
     /**
      * 输出一个Map后的操作
      *
      */
-    public void writeMapE();
+    public abstract void writeMapE();
 
     /**
-     * 输出一个字段
+     * 输出一个字段名
      *
-     * @param comma     是否非第一个字段
      * @param attribute 字段的Attribute对象
      */
-    public void writeField(boolean comma, Attribute attribute);
+    public abstract void writeFieldName(Attribute attribute);
 
     /**
      * 写入一个boolean值
      *
      * @param value boolean值
      */
-    public void writeBoolean(boolean value);
+    public abstract void writeBoolean(boolean value);
 
     /**
      * 写入一个byte值
      *
      * @param value byte值
      */
-    public void writeByte(byte value);
+    public abstract void writeByte(byte value);
 
     /**
      * 写入一个char值
      *
      * @param value char值
      */
-    public void writeChar(char value);
+    public abstract void writeChar(char value);
 
     /**
      * 写入一个short值
      *
      * @param value short值
      */
-    public void writeShort(short value);
+    public abstract void writeShort(short value);
 
     /**
      * 写入一个int值
      *
      * @param value int值
      */
-    public void writeInt(int value);
+    public abstract void writeInt(int value);
 
     /**
      * 写入一个long值
      *
      * @param value long值
      */
-    public void writeLong(long value);
+    public abstract void writeLong(long value);
 
     /**
      * 写入一个float值
      *
      * @param value float值
      */
-    public void writeFloat(float value);
+    public abstract void writeFloat(float value);
 
     /**
      * 写入一个double值
      *
      * @param value double值
      */
-    public void writeDouble(double value);
+    public abstract void writeDouble(double value);
 
     /**
      * 写入无转义字符长度不超过255的字符串， 例如枚举值、字段名、类名字符串等 *
      *
      * @param value 非空且不含需要转义的字符的String值
      */
-    public void writeSmallString(String value);
+    public abstract void writeSmallString(String value);
 
     /**
      * 写入一个String值
      *
      * @param value String值
      */
-    public void writeString(String value);
+    public abstract void writeString(String value);
 }
diff --git a/src/org/redkale/convert/bson/BsonReader.java b/src/org/redkale/convert/bson/BsonReader.java
index b43d4bbe5..13183a27c 100644
--- a/src/org/redkale/convert/bson/BsonReader.java
+++ b/src/org/redkale/convert/bson/BsonReader.java
@@ -5,7 +5,6 @@
  */
 package org.redkale.convert.bson;
 
-import java.util.concurrent.atomic.*;
 import java.util.function.*;
 import org.redkale.convert.*;
 import static org.redkale.convert.Reader.SIGN_NULL;
@@ -19,7 +18,7 @@ import org.redkale.util.*;
  *
  * @author zhangjx
  */
-public class BsonReader implements Reader {
+public class BsonReader extends Reader {
 
     public static final short SIGN_OBJECTB = (short) 0xBB;
 
@@ -156,19 +155,18 @@ public class BsonReader implements Reader {
         }
     }
 
-    /**
-     * 判断下一个非空白字节是否为{
-     *
-     */
     @Override
-    public final int readObjectB() {
+    public final String readObjectB(final Class clazz) {
+        this.fieldIndex = 0; //必须要重置为0
+        final String newcls = readClassName();
+        if (newcls != null && !newcls.isEmpty()) return newcls;
         short bt = readShort();
-        if (bt == Reader.SIGN_NULL) return bt;
+        if (bt == Reader.SIGN_NULL) return null;
         if (bt != SIGN_OBJECTB) {
             throw new ConvertException("a bson object must begin with " + (SIGN_OBJECTB)
                     + " (position = " + position + ") but '" + currentByte() + "'");
         }
-        return bt;
+        return "";
     }
 
     @Override
@@ -230,24 +228,20 @@ public class BsonReader implements Reader {
     }
 
     @Override
-    public final DeMember readField(final AtomicInteger index, final DeMember[] members) {
+    public final DeMember readFieldName(final DeMember[] members) {
         final String exceptedfield = readSmallString();
         this.typeval = readByte();
         final int len = members.length;
-        int v = index.get();
-        if (v >= len) {
-            v = 0;
-            index.set(0);
-        }
-        for (int k = v; k < len; k++) {
+        if (this.fieldIndex >= len) this.fieldIndex = 0;
+        for (int k = this.fieldIndex; k < len; k++) {
             if (exceptedfield.equals(members[k].getAttribute().field())) {
-                index.set(k);
+                this.fieldIndex = k;
                 return members[k];
             }
         }
-        for (int k = 0; k < v; k++) {
+        for (int k = 0; k < this.fieldIndex; k++) {
             if (exceptedfield.equals(members[k].getAttribute().field())) {
-                index.set(k);
+                this.fieldIndex = k;
                 return members[k];
             }
         }
diff --git a/src/org/redkale/convert/bson/BsonWriter.java b/src/org/redkale/convert/bson/BsonWriter.java
index e5de19e23..40c1925d3 100644
--- a/src/org/redkale/convert/bson/BsonWriter.java
+++ b/src/org/redkale/convert/bson/BsonWriter.java
@@ -12,10 +12,12 @@ import org.redkale.util.*;
 
 /**
  *
- * <p> 详情见: http://www.redkale.org
+ * <p>
+ * 详情见: http://www.redkale.org
+ *
  * @author zhangjx
  */
-public class BsonWriter implements Writer {
+public class BsonWriter extends Writer {
 
     private static final int defaultSize = Integer.getInteger("convert.bson.writer.buffer.defsize", 1024);
 
@@ -171,7 +173,8 @@ public class BsonWriter implements Writer {
     }
 
     @Override
-    public final void writeObjectB(int fieldCount, Object obj) {
+    public final void writeObjectB(Object obj) {
+        super.writeObjectB(obj);
         writeSmallString("");
         writeShort(BsonReader.SIGN_OBJECTB);
     }
@@ -183,7 +186,7 @@ public class BsonWriter implements Writer {
     }
 
     @Override
-    public final void writeField(boolean comma, Attribute attribute) {
+    public final void writeFieldName( Attribute attribute) {
         writeByte(BsonReader.SIGN_HASNEXT);
         writeSmallString(attribute.field());
         byte typeval = 127;  //字段的类型值
diff --git a/src/org/redkale/convert/ext/CompletionHandlerSimpledCoder.java b/src/org/redkale/convert/ext/CompletionHandlerSimpledCoder.java
index 2484a4c40..b4882a8a5 100644
--- a/src/org/redkale/convert/ext/CompletionHandlerSimpledCoder.java
+++ b/src/org/redkale/convert/ext/CompletionHandlerSimpledCoder.java
@@ -8,10 +8,12 @@ package org.redkale.convert.ext;
 import java.nio.channels.*;
 import org.redkale.convert.*;
 
-/** 
+/**
  * java.nio.channels.CompletionHandler 的SimpledCoder实现, 只输出null
- * 
- * <p> 详情见: http://www.redkale.org
+ *
+ * <p>
+ * 详情见: http://www.redkale.org
+ *
  * @author zhangjx
  * @param <R> Reader输入的子类型
  * @param <W> Writer输出的子类型
@@ -22,12 +24,12 @@ public final class CompletionHandlerSimpledCoder<R extends Reader, W extends Wri
 
     @Override
     public void convertTo(W out, CompletionHandler value) {
-        out.writeNull();
+        out.writeObjectNull(CompletionHandler.class);
     }
 
     @Override
     public CompletionHandler convertFrom(R in) {
-        in.readObjectB();
+        in.readObjectB(CompletionHandler.class);
         return null;
     }
 
diff --git a/src/org/redkale/convert/json/JsonByteBufferReader.java b/src/org/redkale/convert/json/JsonByteBufferReader.java
index e8ce607ee..3c64f78c0 100644
--- a/src/org/redkale/convert/json/JsonByteBufferReader.java
+++ b/src/org/redkale/convert/json/JsonByteBufferReader.java
@@ -113,11 +113,11 @@ public class JsonByteBufferReader extends JsonReader {
      * @return SIGN_NOLENGTH 或 SIGN_NULL
      */
     @Override
-    public final int readObjectB() {
+    public final String readObjectB(final Class clazz) {
         char ch = nextGoodChar();
-        if (ch == '{') return SIGN_NOLENGTH;
-        if (ch == 'n' && nextChar() == 'u' && nextChar() == 'l' && nextChar() == 'l') return SIGN_NULL;
-        if (ch == 'N' && nextChar() == 'U' && nextChar() == 'L' && nextChar() == 'L') return SIGN_NULL;
+        if (ch == '{') return "";
+        if (ch == 'n' && nextChar() == 'u' && nextChar() == 'l' && nextChar() == 'l') return null;
+        if (ch == 'N' && nextChar() == 'U' && nextChar() == 'L' && nextChar() == 'L') return null;
         throw new ConvertException("a json object text must begin with '{' (position = " + position + ") but '" + ch + "'");
     }
 
diff --git a/src/org/redkale/convert/json/JsonReader.java b/src/org/redkale/convert/json/JsonReader.java
index 837066222..98a3d324a 100644
--- a/src/org/redkale/convert/json/JsonReader.java
+++ b/src/org/redkale/convert/json/JsonReader.java
@@ -5,7 +5,6 @@
  */
 package org.redkale.convert.json;
 
-import java.util.concurrent.atomic.*;
 import java.util.function.*;
 import org.redkale.convert.*;
 import static org.redkale.convert.Reader.*;
@@ -18,7 +17,7 @@ import org.redkale.util.*;
  *
  * @author zhangjx
  */
-public class JsonReader implements Reader {
+public class JsonReader extends Reader {
 
     protected int position = -1;
 
@@ -169,21 +168,23 @@ public class JsonReader implements Reader {
     /**
      * 判断下一个非空白字符是否为{
      *
-     * @return SIGN_NOLENGTH 或 SIGN_NULL
+     * @param clazz 类名
+     * @return 返回 null 表示对象为null， 返回空字符串表示当前class与返回的class一致，返回非空字符串表示class是当前class的子类。
      */
     @Override
-    public int readObjectB() {
+    public String readObjectB(final Class clazz) {
+        this.fieldIndex = 0; //必须要重置为0
         char ch = this.text[++this.position];
-        if (ch == '{') return SIGN_NOLENGTH;
+        if (ch == '{') return "";
         if (ch <= ' ') {
             for (;;) {
                 ch = this.text[++this.position];
                 if (ch > ' ') break;
             }
-            if (ch == '{') return SIGN_NOLENGTH;
+            if (ch == '{') return "";
         }
-        if (ch == 'n' && text[++position] == 'u' && text[++position] == 'l' && text[++position] == 'l') return SIGN_NULL;
-        if (ch == 'N' && text[++position] == 'U' && text[++position] == 'L' && text[++position] == 'L') return SIGN_NULL;
+        if (ch == 'n' && text[++position] == 'u' && text[++position] == 'l' && text[++position] == 'l') return null;
+        if (ch == 'N' && text[++position] == 'U' && text[++position] == 'L' && text[++position] == 'L') return null;
         throw new ConvertException("a json object text must begin with '{' (position = " + position + ") but '" + ch + "' in (" + new String(this.text) + ")");
     }
 
@@ -416,23 +417,19 @@ public class JsonReader implements Reader {
     }
 
     @Override
-    public final DeMember readField(final AtomicInteger index, final DeMember[] members) {
+    public final DeMember readFieldName(final DeMember[] members) {
         final String exceptedfield = this.readSmallString();
         final int len = members.length;
-        int v = index.get();
-        if (v >= len) {
-            v = 0;
-            index.set(0);
-        }
-        for (int k = v; k < len; k++) {
+        if (this.fieldIndex >= len) this.fieldIndex = 0;
+        for (int k = this.fieldIndex; k < len; k++) {
             if (exceptedfield.equals(members[k].getAttribute().field())) {
-                index.set(k);
+                this.fieldIndex = k;
                 return members[k];
             }
         }
-        for (int k = 0; k < v; k++) {
+        for (int k = 0; k < this.fieldIndex; k++) {
             if (exceptedfield.equals(members[k].getAttribute().field())) {
-                index.set(k);
+                this.fieldIndex = k;
                 return members[k];
             }
         }
diff --git a/src/org/redkale/convert/json/JsonWriter.java b/src/org/redkale/convert/json/JsonWriter.java
index 7a2c46dc0..4b4294976 100644
--- a/src/org/redkale/convert/json/JsonWriter.java
+++ b/src/org/redkale/convert/json/JsonWriter.java
@@ -19,7 +19,7 @@ import org.redkale.util.*;
  *
  * @author zhangjx
  */
-public class JsonWriter implements Writer {
+public class JsonWriter extends Writer {
 
     private static final char[] CHARS_TUREVALUE = "true".toCharArray();
 
@@ -159,8 +159,8 @@ public class JsonWriter implements Writer {
     }
 
     @Override
-    public final void writeField(boolean comma, Attribute attribute) {
-        if (comma) writeTo(',');
+    public final void writeFieldName(Attribute attribute) {
+        if (this.comma) writeTo(',');
         writeTo(true, attribute.field());
         writeTo(':');
     }
@@ -225,7 +225,8 @@ public class JsonWriter implements Writer {
     }
 
     @Override
-    public final void writeObjectB(int fieldCount, Object obj) {
+    public final void writeObjectB(Object obj) {
+        super.writeObjectB(obj);
         writeTo('{');
     }