Fastjson SerializerFeature详解

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SerializerFeature属性

名称含义备注 QuoteFieldNames 输出key时是否使用双引号,默认为true UseSingleQuotes 使用单引号而不是双引号,默认为false WriteMapNullValue 是否输出值为null的字段,默认为false WriteEnumUsingToString Enum输出name()或者original,默认为false UseISO8601DateFormat Date使用ISO8601格式输出，默认为false WriteNullListAsEmpty List字段如果为null,输出为[],而非null WriteNullStringAsEmpty 字符类型字段如果为null,输出为”“,而非null WriteNullNumberAsZero 数值字段如果为null,输出为0,而非null WriteNullBooleanAsFalse Boolean字段如果为null,输出为false,而非null SkipTransientField 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 SortField 按字段名称排序后输出。默认为false WriteTabAsSpecial 把\t做转义输出，默认为false 不推荐 PrettyFormat 结果是否格式化,默认为false WriteClassName 序列化时写入类型信息，默认为false。反序列化是需用到 DisableCircularReferenceDetect 消除对同一对象循环引用的问题，默认为false WriteSlashAsSpecial 对斜杠’/’进行转义 BrowserCompatible 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 WriteDateUseDateFormat 全局修改日期格式,默认为false。JSON.DEFFAULT_DATE_FORMAT = “yyyy-MM-dd”;JSON.toJSONString(obj, SerializerFeature.WriteDateUseDateFormat); DisableCheckSpecialChar 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 NotWriteRootClassName 含义 BeanToArray 将对象转为array输出 WriteNonStringKeyAsString 含义 NotWriteDefaultValue 含义 BrowserSecure 含义 IgnoreNonFieldGetter 含义 WriteEnumUsingName 含义

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;    }

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;    }

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));    }}

对应输出结果如下：

1、useSingleQuotes：
2、writeMapNullValue：
3、useISO8601DateFormat：
4、writeNullListAsEmpty：
5、writeNullStringAsEmpty：
6、prettyFormat：
7、writeDateUseDateFormat：
8、beanToArray：
9、自定义组合：showJsonBySelf：

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":[{"$ref</span>":<span class="hljs-value"><span class="hljs-string">"$.list[0]"},{"$ref</span>":<span class="hljs-value"><span class="hljs-string">"$.list[1]"},null,{"$ref</span>":<span class="hljs-value"><span class="hljs-string">"$.list[3]"}],"user3":{"$ref</span>":<span class="hljs-value"><span class="hljs-string">"$.list[0]"},"mapz":"mapz","mapo":"mapo","mapa":"mapa","user1":{"$ref</span>":<span class="hljs-value"><span class="hljs-string">"$.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"        }    }}

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