Json转换凶器Gson之实例三-Map处理(上) _JavaScript

Json转换利器Gson之实例三-Map处理(上)

Map的存储结构式Key/Value形式,Key 和 Value可以是普通类型,也可以是自己写的JavaBean(本文),还可以是带有泛型的List(下一篇博客).本例中您要重点看如何将Json转回为普通JavaBean对象时TypeToken的定义.

实体类:

public?class?Point?{??
????private?int?x;??
????private?int?y;??
??
????public?Point(int?x,?int?y)?{??
????????this.x?=?x;??
????????this.y?=?y;??
????}??
??
????public?int?getX()?{??
????????return?x;??
????}??
??
????public?void?setX(int?x)?{??
????????this.x?=?x;??
????}??
??
????public?int?getY()?{??
????????return?y;??
????}??
??
????public?void?setY(int?y)?{??
????????this.y?=?y;??
????}??
??
????@Override??
????public?String?toString()?{??
????????return?"Point?[x="?+?x?+?",?y="?+?y?+?"]";??
????}??
??
}??

测试类:

import?java.util.LinkedHashMap;??
import?java.util.Map;??
??
import?com.google.gson.Gson;??
import?com.google.gson.GsonBuilder;??
import?com.google.gson.reflect.TypeToken;??
??
public?class?GsonTest3?{??
??
????public?static?void?main(String[]?args)?{??
????????Gson?gson?=?new?GsonBuilder().enableComplexMapKeySerialization()??
????????????????.create();??
??
????????Map<Point,?String>?map1?=?new?LinkedHashMap<Point,?String>();//?使用LinkedHashMap将结果按先进先出顺序排列??
????????map1.put(new?Point(5,?6),?"a");??
????????map1.put(new?Point(8,?8),?"b");??
????????String?s?=?gson.toJson(map1);??
????????System.out.println(s);//?结果:[[{"x":5,"y":6},"a"],[{"x":8,"y":8},"b"]]??
??
????????Map<Point,?String>?retMap?=?gson.fromJson(s,??
????????????????new?TypeToken<Map<Point,?String>>()?{??
????????????????}.getType());??
????????for?(Point?p?:?retMap.keySet())?{??
????????????System.out.println("key:"?+?p?+?"?values:"?+?retMap.get(p));??
????????}??
????????System.out.println(retMap);??
??
????????System.out.println("----------------------------------");??
????????Map<String,?Point>?map2?=?new?LinkedHashMap<String,?Point>();??
????????map2.put("a",?new?Point(3,?4));??
????????map2.put("b",?new?Point(5,?6));??
????????String?s2?=?gson.toJson(map2);??
????????System.out.println(s2);??
??
????????Map<String,?Point>?retMap2?=?gson.fromJson(s2,??
????????????????new?TypeToken<Map<String,?Point>>()?{??
????????????????}.getType());??
????????for?(String?key?:?retMap2.keySet())?{??
????????????System.out.println("key:"?+?key?+?"?values:"?+?retMap2.get(key));??
????????}??
??
????}??
}??

结果:

[[{"x":5,"y":6},"a"],[{"x":8,"y":8},"b"]]??
key:Point?[x=5,?y=6]?values:a??
key:Point?[x=8,?y=8]?values:b??
{Point?[x=5,?y=6]=a,?Point?[x=8,?y=8]=b}??
----------------------------------??
{"a":{"x":3,"y":4},"b":{"x":5,"y":6}}??
key:a?values:Point?[x=3,?y=4]??
key:b?values:Point?[x=5,?y=6]??