新增SerializerFeature.WriteEnumUsingName用于在序列化时输出枚举的name()值。

Release Notes(1.1.42) https://github.com/alibaba/fastjson/wiki/Release-Notes(1.1.42)  “修复序列化时SerializerFeature.WriteEnumUsingToString不生效的bug“，这种做法会引起问题。如果重写了枚举的toString方法，会导致反序列化失败。而且，此fix (https://github.com/alibaba/fastjson/commit/6a2b502455b54367cc2554eb5e00d27056c07f13)只修改了部分代码，还有几个地方在启用WriteEnumUsingToString特性时，仍然使用name()。

此修改序列化枚举时默认用枚举的name()值，和以前的版本保持一致，并且修改了所有使用WriteEnumUsingToString特性的代码，让他真正生效。

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

@@ -88,7 +88,7 @@ public abstract class JSON implements JSONStreamAware, JSONAware {
         int features = 0;
         features |= SerializerFeature.QuoteFieldNames.getMask();
         features |= SerializerFeature.SkipTransientField.getMask();
-        features |= SerializerFeature.WriteEnumUsingToString.getMask();
+        features |= SerializerFeature.WriteEnumUsingName.getMask();
         features |= SerializerFeature.SortField.getMask();
         // features |=
         // com.alibaba.fastjson.serializer.SerializerFeature.WriteSlashAsSpecial.getMask();

src/main/java/com/alibaba/fastjson/serializer/EnumSerializer.java

@@ -32,11 +32,12 @@ public class EnumSerializer implements ObjectSerializer {
             return;
         }
 
-        if (serializer.isEnabled(SerializerFeature.WriteEnumUsingToString)) {
-            Enum<?> e = (Enum<?>) object;
+        Enum<?> e = (Enum<?>) object;
+        if(serializer.isEnabled(SerializerFeature.WriteEnumUsingName)){
+            serializer.write(e.name());
+        } else if (serializer.isEnabled(SerializerFeature.WriteEnumUsingToString)) {
             serializer.write(e.toString());
         } else {
-            Enum<?> e = (Enum<?>) object;
             out.writeInt(e.ordinal());
         }
     }

src/main/java/com/alibaba/fastjson/serializer/ObjectFieldSerializer.java

@@ -15,11 +15,11 @@
  */
 package com.alibaba.fastjson.serializer;
 
-import java.util.Collection;
-
 import com.alibaba.fastjson.annotation.JSONField;
 import com.alibaba.fastjson.util.FieldInfo;
 
+import java.util.Collection;
+
 /**
  * @author wenshao[szujobs@hotmail.com]
  */
@@ -31,6 +31,7 @@ public class ObjectFieldSerializer extends FieldSerializer {
     boolean                       writeNullBooleanAsFalse = false;
     boolean                       writeNullListAsEmpty    = false;
     boolean                       writeEnumUsingToString  = false;
+    boolean                       writeEnumUsingName      = false;
 
     private RuntimeSerializerInfo runtimeInfo;
 
@@ -57,6 +58,8 @@ public class ObjectFieldSerializer extends FieldSerializer {
                     writeNullListAsEmpty = true;
                 } else if (feature == SerializerFeature.WriteEnumUsingToString) {
                     writeEnumUsingToString = true;
+                }else if(feature == SerializerFeature.WriteEnumUsingName){
+                    writeEnumUsingName = true;
                 }
             }
         }
@@ -110,9 +113,15 @@ public class ObjectFieldSerializer extends FieldSerializer {
             return;
         }
 
-        if (writeEnumUsingToString == true && runtimeInfo.runtimeFieldClass.isEnum()) {
-            serializer.getWriter().writeString(((Enum<?>) propertyValue).name());
-            return;
+        if(runtimeInfo.runtimeFieldClass.isEnum()){
+            if(writeEnumUsingName){
+                serializer.getWriter().writeString(((Enum<?>) propertyValue).name());
+                return;
+            }
+            if(writeEnumUsingToString){
+                serializer.getWriter().writeString(((Enum<?>) propertyValue).toString());
+                return;
+            }
         }
 
         Class<?> valueClass = propertyValue.getClass();

src/main/java/com/alibaba/fastjson/serializer/SerializeWriter.java

@@ -115,6 +115,12 @@ public final class SerializeWriter extends Writer {
     public void config(SerializerFeature feature, boolean state) {
         if (state) {
             features |= feature.getMask();
+            //由于枚举序列化特性WriteEnumUsingToString和WriteEnumUsingName不能共存，需要检查
+            if(feature == SerializerFeature.WriteEnumUsingToString){
+                features &= ~SerializerFeature.WriteEnumUsingName.getMask();
+            }else if(feature == SerializerFeature.WriteEnumUsingName){
+                features &= ~SerializerFeature.WriteEnumUsingToString.getMask();
+            }
         } else {
             features &= ~feature.getMask();
         }
@@ -499,25 +505,34 @@ public final class SerializeWriter extends Writer {
             return;
         }
 
-        if (isEnabled(SerializerFeature.WriteEnumUsingToString)) {
-            if (isEnabled(SerializerFeature.UseSingleQuotes)) {
-                write('\'');
-                write(value.name());
-                write('\'');
-                write(c);
+        if (isEnabled(SerializerFeature.WriteEnumUsingName)) {
+            writeEnumValue(value.name(),c);
+            return;
+        }
 
-            } else {
-                write('\"');
-                write(value.name());
-                write('\"');
-                write(c);
-            }
+        if (isEnabled(SerializerFeature.WriteEnumUsingToString)) {
+            writeEnumValue(value.toString(),c);
             return;
         }
 
         writeIntAndChar(value.ordinal(), c);
     }
 
+    private void writeEnumValue(String value,char c){
+        if (isEnabled(SerializerFeature.UseSingleQuotes)) {
+            write('\'');
+            write(value);
+            write('\'');
+            write(c);
+
+        } else {
+            write('\"');
+            write(value);
+            write('\"');
+            write(c);
+        }
+    }
+
     public void writeIntAndChar(int i, char c) {
         if (i == Integer.MIN_VALUE) {
             write("-2147483648");
@@ -1423,20 +1438,23 @@ public final class SerializeWriter extends Writer {
             return;
         }
 
-        if (isEnabled(SerializerFeature.WriteEnumUsingToString)) {
-            if (isEnabled(SerializerFeature.UseSingleQuotes)) {
-                writeFieldValue(seperator, name, value.name());
-            } else {
-                writeFieldValueStringWithDoubleQuote(seperator, name, value.name(), false);
-                return;
-            }
-
-            // writeStringWithDoubleQuote
+        if (isEnabled(SerializerFeature.WriteEnumUsingName)) {
+            writeEnumFieldValue(seperator,name,value.name());
+        }else if(isEnabled(SerializerFeature.WriteEnumUsingToString)){
+            writeEnumFieldValue(seperator,name,value.toString());
         } else {
             writeFieldValue(seperator, name, value.ordinal());
         }
     }
 
+    private void writeEnumFieldValue(char seperator,String name,String value){
+        if (isEnabled(SerializerFeature.UseSingleQuotes)) {
+            writeFieldValue(seperator, name, value);
+        } else {
+            writeFieldValueStringWithDoubleQuote(seperator, name, value, false);
+        }
+    }
+
     public void writeFieldValue(char seperator, String name, BigDecimal value) {
         write(seperator);
         writeFieldName(name);

src/main/java/com/alibaba/fastjson/serializer/SerializerFeature.java

@@ -29,9 +29,13 @@ public enum SerializerFeature {
      */
     WriteMapNullValue,
     /**
-     * 
+     * 用枚举toString()值输出
      */
     WriteEnumUsingToString,
+    /**
+     * 用枚举name()输出
+     */
+    WriteEnumUsingName,
     /**
      * 
      */

src/test/java/com/alibaba/json/bvt/serializer/EnumTest3.java

@@ -0,0 +1,129 @@
+/*
+ * www.yiji.com Inc.
+ * Copyright (c) 2014 All Rights Reserved
+ */
+
+/*
+ * 修订记录:
+ * qzhanbo@yiji.com 2015-03-01 00:55 创建
+ *
+ */
+package com.alibaba.json.bvt.serializer;
+
+import com.alibaba.fastjson.JSON;
+import com.alibaba.fastjson.serializer.SerializeWriter;
+import com.alibaba.fastjson.serializer.SerializerFeature;
+import org.junit.Assert;
+import org.junit.Test;
+
+import java.util.EnumMap;
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * @author bohr.qiu@gmail.com
+ */
+public class EnumTest3 {
+	@Test
+	public void testDefault() throws Exception {
+		String json = JSON.toJSONString(Sex.M);
+		Assert.assertEquals(json, "\"M\"");
+		
+		Pojo pojo = new Pojo();
+		pojo.setSex(Sex.M);
+		json = JSON.toJSONString(pojo);
+		Assert.assertEquals(json, "{\"sex\":\"M\"}");
+
+        try {
+            JSON.parseObject(json, Pojo.class);
+            Assert.assertTrue(true);
+        } catch (Exception e) {
+            Assert.fail("枚举默认序列化name值，可以反序列化成功");
+        }
+
+		Map<String, Pojo> map = new HashMap<String, Pojo>();
+		map.put("a", pojo);
+		json = JSON.toJSONString(map);
+		Assert.assertEquals(json, "{\"a\":{\"sex\":\"M\"}}");
+		
+		Map<Sex, Pojo> enumMap = new EnumMap<Sex, Pojo>(Sex.class);
+		enumMap.put(Sex.M, pojo);
+		json = JSON.toJSONString(enumMap);
+		Assert.assertEquals(json, "{\"M\":{\"sex\":\"M\"}}");
+	}
+
+    @Test
+    public void testDefault1() throws Exception {
+        JSON.DUMP_CLASS = "/Users/bohr/Downloads/tmp";
+        String json = JSON.toJSONString(Sex.M, SerializerFeature.WriteEnumUsingToString);
+        Assert.assertEquals(json, "\"男\"");
+
+        Pojo pojo = new Pojo();
+        pojo.setSex(Sex.M);
+        json = JSON.toJSONString(pojo, SerializerFeature.WriteEnumUsingToString);
+        Assert.assertEquals(json, "{\"sex\":\"男\"}");
+
+        try {
+            JSON.parseObject(json, Pojo.class);
+            Assert.fail("toString的结果不能转换成枚举");
+        } catch (Exception e) {
+            Assert.assertTrue(true);
+        }
+
+        Map<String, Pojo> map = new HashMap<String, Pojo>();
+        map.put("a", pojo);
+        json = JSON.toJSONString(map, SerializerFeature.WriteEnumUsingToString);
+        Assert.assertEquals(json, "{\"a\":{\"sex\":\"男\"}}");
+
+        Map<Sex, Pojo> enumMap = new EnumMap<Sex, Pojo>(Sex.class);
+        enumMap.put(Sex.M, pojo);
+        json = JSON.toJSONString(enumMap, SerializerFeature.WriteEnumUsingToString);
+        Assert.assertEquals(json, "{\"男\":{\"sex\":\"男\"}}");
+    }
+
+    @Test
+    public void testName() throws Exception {
+        Assert.assertEquals("\"男\"", JSON.toJSONString(Sex.M, SerializerFeature.WriteEnumUsingToString));
+        Assert.assertEquals("\"女\"", JSON.toJSONString(Sex.W, SerializerFeature.WriteEnumUsingToString));
+    }
+
+    @Test
+    public void testWriterSerializerFeature() throws Exception {
+        SerializeWriter writer=new SerializeWriter();
+        writer.config(SerializerFeature.WriteEnumUsingToString,true);
+        Assert.assertTrue(writer.isEnabled(SerializerFeature.WriteEnumUsingToString));
+        writer.config(SerializerFeature.WriteEnumUsingName,true);
+        Assert.assertTrue(writer.isEnabled(SerializerFeature.WriteEnumUsingName));
+        Assert.assertFalse(writer.isEnabled(SerializerFeature.WriteEnumUsingToString));
+        writer.config(SerializerFeature.WriteEnumUsingToString,true);
+        Assert.assertTrue(writer.isEnabled(SerializerFeature.WriteEnumUsingToString));
+        Assert.assertFalse(writer.isEnabled(SerializerFeature.WriteEnumUsingName));
+    }
+
+    public static enum Sex {
+		M("男"),
+		W("女");
+		private String msg;
+		
+		Sex(String msg) {
+			this.msg = msg;
+		}
+		
+		@Override
+		public String toString() {
+			return msg;
+		}
+	}
+	
+	public static class Pojo {
+		private Sex sex;
+		
+		public Sex getSex() {
+			return sex;
+		}
+		
+		public void setSex(Sex sex) {
+			this.sex = sex;
+		}
+	}
+}