深入理解Fastjson序列化特性SerializerFeature
最编程
2024-02-11 15:41:46
...
依赖
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>fastjson</artifactId>
<version>1.2.7</version>
</dependency>
<dependency> <groupId>com.alibaba</groupId> <artifactId>fastjson</artifactId> <version>1.2.7</version> </dependency>
SerializerFeature属性
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;
}
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:
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