fastjson SerializerFeature详解

系统管理员 2022-05-20 01:52 141阅读 0赞

# fastjson SerializerFeature详解 #

# 依赖 #

<dependency>
                <groupId>com.alibaba</groupId>
                <artifactId>fastjson</artifactId>
                <version>1.2.7</version>
            </dependency>

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# SerializerFeature属性 #

<table> 
 <thead> 
  <tr> 
   <th align="center">名称</th> 
   <th align="center">含义</th> 
   <th align="center">备注</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td align="center">QuoteFieldNames</td> 
   <td align="center">输出key时是否使用双引号,默认为true</td> 
   <td align="center">&nbsp;</td> 
  </tr> 
  <tr> 
   <td align="center">UseSingleQuotes</td> 
   <td align="center">使用单引号而不是双引号,默认为false</td> 
   <td align="center">&nbsp;</td> 
  </tr> 
  <tr> 
   <td align="center">WriteMapNullValue</td> 
   <td align="center">是否输出值为null的字段,默认为false</td> 
   <td align="center">&nbsp;</td> 
  </tr> 
  <tr> 
   <td align="center">WriteEnumUsingToString</td> 
   <td align="center">Enum输出name()或者original,默认为false</td> 
   <td align="center">&nbsp;</td> 
  </tr> 
  <tr> 
   <td align="center">UseISO8601DateFormat</td> 
   <td align="center">Date使用ISO8601格式输出，默认为false</td> 
   <td align="center">&nbsp;</td> 
  </tr> 
  <tr> 
   <td align="center">WriteNullListAsEmpty</td> 
   <td align="center">List字段如果为null,输出为[],而非null</td> 
   <td align="center">&nbsp;</td> 
  </tr> 
  <tr> 
   <td align="center">WriteNullStringAsEmpty</td> 
   <td align="center">字符类型字段如果为null,输出为”“,而非null</td> 
   <td align="center">&nbsp;</td> 
  </tr> 
  <tr> 
   <td align="center">WriteNullNumberAsZero</td> 
   <td align="center">数值字段如果为null,输出为0,而非null</td> 
   <td align="center">&nbsp;</td> 
  </tr> 
  <tr> 
   <td align="center">WriteNullBooleanAsFalse</td> 
   <td align="center">Boolean字段如果为null,输出为false,而非null</td> 
   <td align="center">&nbsp;</td> 
  </tr> 
  <tr> 
   <td align="center">SkipTransientField</td> 
   <td align="center">如果是true，类中的Get方法对应的Field是transient，序列化时将会被忽略。默认为true</td> 
   <td align="center">&nbsp;</td> 
  </tr> 
  <tr> 
   <td align="center">SortField</td> 
   <td align="center">按字段名称排序后输出。默认为false</td> 
   <td align="center">&nbsp;</td> 
  </tr> 
  <tr> 
   <td align="center">WriteTabAsSpecial</td> 
   <td align="center">把\t做转义输出，默认为false</td> 
   <td align="center"><code>不推荐</code></td> 
  </tr> 
  <tr> 
   <td align="center">PrettyFormat</td> 
   <td align="center">结果是否格式化,默认为false</td> 
   <td align="center">&nbsp;</td> 
  </tr> 
  <tr> 
   <td align="center">WriteClassName</td> 
   <td align="center">序列化时写入类型信息，默认为false。反序列化是需用到</td> 
   <td align="center">&nbsp;</td> 
  </tr> 
  <tr> 
   <td align="center">DisableCircularReferenceDetect</td> 
   <td align="center">消除对同一对象循环引用的问题，默认为false</td> 
   <td align="center">&nbsp;</td> 
  </tr> 
  <tr> 
   <td align="center">WriteSlashAsSpecial</td> 
   <td align="center">对斜杠’/’进行转义</td> 
   <td align="center">&nbsp;</td> 
  </tr> 
  <tr> 
   <td align="center">BrowserCompatible</td> 
   <td align="center">将中文都会序列化为\uXXXX格式，字节数会多一些，但是能兼容IE 6，默认为false</td> 
   <td align="center">&nbsp;</td> 
  </tr> 
  <tr> 
   <td align="center">WriteDateUseDateFormat</td> 
   <td align="center">全局修改日期格式,默认为false。JSON.DEFFAULT_DATE_FORMAT = “yyyy-MM-dd”;JSON.toJSONString(obj, SerializerFeature.WriteDateUseDateFormat);</td> 
   <td align="center">&nbsp;</td> 
  </tr> 
  <tr> 
   <td align="center">DisableCheckSpecialChar</td> 
   <td align="center">一个对象的字符串属性中如果有特殊字符如双引号，将会在转成json时带有反斜杠转移符。如果不需要转义，可以使用这个属性。默认为false</td> 
   <td align="center">&nbsp;</td> 
  </tr> 
  <tr> 
   <td align="center">NotWriteRootClassName</td> 
   <td align="center">含义</td> 
   <td align="center">&nbsp;</td> 
  </tr> 
  <tr> 
   <td align="center">BeanToArray</td> 
   <td align="center">将对象转为array输出</td> 
   <td align="center">&nbsp;</td> 
  </tr> 
  <tr> 
   <td align="center">WriteNonStringKeyAsString</td> 
   <td align="center">含义</td> 
   <td align="center">&nbsp;</td> 
  </tr> 
  <tr> 
   <td align="center">NotWriteDefaultValue</td> 
   <td align="center">含义</td> 
   <td align="center">&nbsp;</td> 
  </tr> 
  <tr> 
   <td align="center">BrowserSecure</td> 
   <td align="center">含义</td> 
   <td align="center">&nbsp;</td> 
  </tr> 
  <tr> 
   <td align="center">IgnoreNonFieldGetter</td> 
   <td align="center">含义</td> 
   <td align="center">&nbsp;</td> 
  </tr> 
  <tr> 
   <td align="center">WriteEnumUsingName</td> 
   <td align="center">含义</td> 
   <td align="center">&nbsp;</td> 
  </tr> 
 </tbody> 
</table>

# 示例 #

## 准备 ##

*  User、Word来模拟各种数据类型。
 *  SerializerFeatureTest：JSON部分示例的示例方法。

## User类型：缺省get、set方法 ##

public class User {
    
        private int id;
        private String name;
        private String add;
        private String old;
        }

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## Word类型：缺省get、set方法 ##

public class Word {
    
        private String d;
        private String e;
        private String f;
        private String a;
        private int b;
        private boolean c;
        private Date date;
        private Map<String , Object> map;
        private List<User> list;
        }

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### SerializerFeatureTest:测试类 ###

public class SerializerFeatureTest { 
    
        private static Word word;
    
        private static void init() {
            word = new Word();
            word.setA("a");
            word.setB(2);
            word.setC(true);
            word.setD("d");
            word.setE("");
            word.setF(null);
            word.setDate(new Date());
    
            List<User> list = new ArrayList<User>();
            User user1 = new User();
            user1.setId(1);
            user1.setOld("11");
            user1.setName("用户1");
            user1.setAdd("北京");
            User user2 = new User();
            user2.setId(2);
            user2.setOld("22");
            user2.setName("用户2");
            user2.setAdd("上海");
            User user3 = new User();
            user3.setId(3);
            user3.setOld("33");
            user3.setName("用户3");
            user3.setAdd("广州");
    
            list.add(user3);
            list.add(user2);
            list.add(null);
            list.add(user1);
    
            word.setList(list);
    
            Map<String , Object> map = new HashedMap();
            map.put("mapa", "mapa");
            map.put("mapo", "mapo");
            map.put("mapz", "mapz");
            map.put("user1", user1);
            map.put("user3", user3);
            map.put("user4", null);
            map.put("list", list);
            word.setMap(map);
        }
    
        public static void main(String[] args) {
            init();
    // useSingleQuotes();
    // writeMapNullValue();
    // useISO8601DateFormat();
    // writeNullListAsEmpty();
    // writeNullStringAsEmpty();
    // sortField();
    // prettyFormat();
    // writeDateUseDateFormat();
    // beanToArray();
            showJsonBySelf();
        }
    
        /** * 9:自定义 * 格式化输出 * 显示值为null的字段 * 将为null的字段值显示为"" * DisableCircularReferenceDetect:消除循环引用 */
        private static void showJsonBySelf() {
            System.out.println(JSON.toJSONString(word));
            System.out.println(JSON.toJSONString(word, SerializerFeature.PrettyFormat,
                    SerializerFeature.WriteMapNullValue, SerializerFeature.WriteNullStringAsEmpty,
                    SerializerFeature.DisableCircularReferenceDetect,
                    SerializerFeature.WriteNullListAsEmpty));
        }
    
        /** * 8: * 将对象转为array输出 */
        private static void beanToArray() {
            word.setMap(null);
            word.setList(null);
            System.out.println(JSON.toJSONString(word));
            System.out.println(JSON.toJSONString(word, SerializerFeature.BeanToArray));
        }
    
        /** * 7: * WriteDateUseDateFormat:全局修改日期格式,默认为false。 */
        private static void writeDateUseDateFormat() {
            word.setMap(null);
            word.setList(null);
            System.out.println(JSON.toJSONString(word));
            JSON.DEFFAULT_DATE_FORMAT = "yyyy-MM-dd";
            System.out.println(JSON.toJSONString(word, SerializerFeature.WriteDateUseDateFormat));
        }
    
        /** * 6: * PrettyFormat */
        private static void prettyFormat() {
            word.setMap(null);
            word.setList(null);
            System.out.println(JSON.toJSONString(word));
            System.out.println(JSON.toJSONString(word, SerializerFeature.PrettyFormat));
        }
    
        /** * SortField:按字段名称排序后输出。默认为false * 这里使用的是fastjson：为了更好使用sort field martch优化算法提升parser的性能，fastjson序列化的时候， * 缺省把SerializerFeature.SortField特性打开了。 * 反序列化的时候也缺省把SortFeidFastMatch的选项打开了。 * 这样，如果你用fastjson序列化的文本，输出的结果是按照fieldName排序输出的，parser时也能利用这个顺序进行优化读取。 * 这种情况下，parser能够获得非常好的性能。 */
        private static void sortField() {
            System.out.println(JSON.toJSONString(word));
            System.out.println(JSON.toJSONString(word, SerializerFeature.SortField));
        }
    
        /** * 5: * WriteNullStringAsEmpty:字符类型字段如果为null,输出为"",而非null * 需要配合WriteMapNullValue使用，现将null输出 */
        private static void writeNullStringAsEmpty() {
            word.setE(null);
            System.out.println(JSONObject.toJSONString(word));
            System.out.println("设置WriteMapNullValue后：");
            System.out.println(JSONObject.toJSONString(word, SerializerFeature.WriteMapNullValue));
            System.out.println("设置WriteMapNullValue、WriteNullStringAsEmpty后：");
            System.out.println(JSONObject.toJSONString(word, SerializerFeature.WriteMapNullValue, SerializerFeature.WriteNullStringAsEmpty));
        }
    
    
        /** * 4: * WriteNullListAsEmpty:List字段如果为null,输出为[],而非null * 需要配合WriteMapNullValue使用，现将null输出 */
        private static void writeNullListAsEmpty() {
            word.setList(null);
            System.out.println(JSONObject.toJSONString(word));
            System.out.println("设置WriteNullListAsEmpty后：");
            System.out.println(JSONObject.toJSONString(word, SerializerFeature.WriteMapNullValue, SerializerFeature.WriteNullListAsEmpty));
        }
    
        /** * 3: * UseISO8601DateFormat:Date使用ISO8601格式输出，默认为false */
        private static void useISO8601DateFormat() {
            System.out.println(JSONObject.toJSONString(word));
            System.out.println("设置UseISO8601DateFormat后：");
            System.out.println(JSONObject.toJSONString(word, SerializerFeature.UseISO8601DateFormat));
        }
    
        /** * 2: * WriteMapNullValue:是否输出值为null的字段,默认为false */
        private static void writeMapNullValue() {
            System.out.println(JSONObject.toJSONString(word));
            System.out.println("设置WriteMapNullValue后：");
            System.out.println(JSONObject.toJSONString(word, SerializerFeature.WriteMapNullValue));
        }
    
        /** * 1: * UseSingleQuotes:使用单引号而不是双引号,默认为false */
        private static void useSingleQuotes() {
            System.out.println(JSONObject.toJSONString(word));
            System.out.println("设置useSingleQuotes后：");
            System.out.println(JSONObject.toJSONString(word, SerializerFeature.UseSingleQuotes));
        }
    }

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## 对应输出结果如下： ##

*  1、useSingleQuotes：  
    ![这里写图片描述][20160914162745717]
 *  2、writeMapNullValue：  
    ![这里写图片描述][20160914162804474]
 *  3、useISO8601DateFormat：  
    ![这里写图片描述][20160914162819850]
 *  4、writeNullListAsEmpty：  
    ![这里写图片描述][20160914162835389]
 *  5、writeNullStringAsEmpty：  
    ![这里写图片描述][20160914162849530]
 *  6、prettyFormat：  
    ![这里写图片描述][20160914162904593]
 *  7、writeDateUseDateFormat：  
    ![这里写图片描述][20160914162919077]
 *  8、beanToArray：  
    ![这里写图片描述][20160914162933874]
 *  9、自定义组合：showJsonBySelf：  
    ![这里写图片描述][20160914162947258]  
    此时完整的输出如下：

{"a":"a","b":2,"c":true,"d":"d","date":1473839656840,"e":"","list":[{"add":"广州","id":3,"name":"用户3","old":"33"},{"add":"上海","id":2,"name":"用户2","old":"22"},null,{"add":"北京","id":1,"name":"用户1","old":"11"}],"map":{"list":[{"$ref":"$.list[0]"},{"$ref":"$.list[1]"},null,{"$ref":"$.list[3]"}],"user3":{"$ref":"$.list[0]"},"mapz":"mapz","mapo":"mapo","mapa":"mapa","user1":{"$ref":"$.list[3]"}}}
    {
        "a":"a",
        "b":2,
        "c":true,
        "d":"d",
        "date":1473839656840,
        "e":"",
        "f":"",
        "list":[ { "add":"广州", "id":3, "name":"用户3", "old":"33" }, { "add":"上海", "id":2, "name":"用户2", "old":"22" }, null, { "add":"北京", "id":1, "name":"用户1", "old":"11" } ],
        "map":{ "list":[ { "add":"广州", "id":3, "name":"用户3", "old":"33" }, { "add":"上海", "id":2, "name":"用户2", "old":"22" }, null, { "add":"北京", "id":1, "name":"用户1", "old":"11" } ], "user4":null, "user3":{ "add":"广州", "id":3, "name":"用户3", "old":"33" }, "mapz":"mapz", "mapo":"mapo", "mapa":"mapa", "user1":{ "add":"北京", "id":1, "name":"用户1", "old":"11" } } }

注意：  
\- [fastjson把对象转化成json避免$ref][fastjson_json_ref]

学习地址：  
\- [http://blog.csdn.net/glarystar/article/details/6654494][http_blog.csdn.net_glarystar_article_details_6654494]  
\- [http://blog.csdn.net/u013163567/article/details/50736096][http_blog.csdn.net_u013163567_article_details_50736096]

项目github地址：  
\- [https://github.com/gubaijin/buildmavenweb][https_github.com_gubaijin_buildmavenweb]

[20160914162745717]: /images/20220520/23d79c88ae82410da665b518d7e05937.png
[20160914162804474]: /images/20220520/eb9a12286a664007b37ec6618d856aae.png
[20160914162819850]: /images/20220520/b3e2323c0ae44a80ab256de721434332.png
[20160914162835389]: /images/20220520/882420302adb4b46a82739588cc62517.png
[20160914162849530]: /images/20220520/3cfb3713e1b847bdab51cd2263cee2ab.png
[20160914162904593]: /images/20220520/3b31d09a5ab14633b88afbaf0e468536.png
[20160914162919077]: /images/20220520/fe89ac0a85de4c139952ee29a6f7376c.png
[20160914162933874]: /images/20220520/9abae3a8a5f74acf826b436758a4f990.png
[20160914162947258]: /images/20220520/de0972b98d67471082a6b1d0123a4af1.png
[fastjson_json_ref]: http://blog.csdn.net/u010246789/article/details/52538953
[http_blog.csdn.net_glarystar_article_details_6654494]: http://blog.csdn.net/glarystar/article/details/6654494
[http_blog.csdn.net_u013163567_article_details_50736096]: http://blog.csdn.net/u013163567/article/details/50736096
[https_github.com_gubaijin_buildmavenweb]: https://github.com/gubaijin/buildmavenweb