Json工具类库之Gson实战笔记

日常接口的数据传输通常使用xml或者json来传递数据，xml较庞大但是描述数据能力十分出众，json数据结构较小而且支持ajax传输，xml在数据传输和解析资源占用都比较逊色于json。因此日常的接口通常都使用json的数据格式进行传输。一方面能减少应用或者客户端如Android应用解析数据的资源占用，另一方面节省宝贵的数据传输时间。

Java中对Json的序列化和反序列化常用的工具有Json、Fastjson、Gson等。其中，Fastjson是阿里巴巴的开源产品，用Java语言实现，号称是速度最快的Json序列化工具。

今天学习了Gson工具，并做了Demo加深学习印象，直接贴上代码在代码中说明问题：

Person类:

/*
 * Copyright 2013 Alibaba.com All right reserved. This software is the
 * confidential and proprietary information of Alibaba.com ("Confidential
 * Information"). You shall not disclose such Confidential Information and shall
 * use it only in accordance with the terms of the license agreement you entered
 * into with Alibaba.com.
 */
package com.yunos.tv.common.util;

import java.lang.reflect.Type;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import com.google.gson.Gson;
import com.google.gson.reflect.TypeToken;

/**
 * 类GsonTest.java的实现描述：TODO 类实现描述
 * @author riqi 2013年8月5日 下午10:26:28
 */

class Person {

    private String name;

    private int    age;

    private Family family;

    public Person(String name, int age, Family family) {
        super();
        this.name = name;
        this.age = age;
        this.family = family;
    }

    public Family getFamily() {
        return family;
    }

    public void setFamily(Family family) {
        this.family = family;
    }

    @Override
    public String toString() {
        return "Person [name=" + name + ", age=" + age + ", family=" + family + "]";
    }
}

Family类:

class Family {

    private String father;

    private String mother;

    public Family(String father, String mother) {
        super();
        this.father = father;
        this.mother = mother;
    }

    @Override
    public String toString() {
        return "Family [father=" + father + ", mother=" + mother + "]";
    }

}

测试过程:

public class GsonTest {

    public static Gson gson = new Gson();

    public static void main(String[] args) {
        String name = "riqi";
        int age = 26;
        Family family = new Family("爸爸", "妈妈");

        // 序列化Map
        Map<String, Object> userMap = new HashMap<String, Object>();
        userMap.put("name", name);
        userMap.put("age", age);
        System.out.println(gson.toJson(userMap)); //{"age":26,"name":"riqi"}

        // 序列化List
        List<Object> userList = new ArrayList<Object>();
        userList.add(name);
        userList.add(age);
        System.out.println(gson.toJson(userList)); //["riqi",26]

        // 序列化对象
        System.out.println(gson.toJson(family)); //{"father":"爸爸","mother":"妈妈"}

        // 借助TypeToken泛型实现单个对象序列化和反序列化
        Person person = new Person(name, age, family);
        Type personType = new TypeToken<Person>() {
        }.getType();
        String personJsonTo = gson.toJson(person, personType);
        Person personJsonFrom = gson.fromJson(personJsonTo, personType);
        Family familyJsonFrom = personJsonFrom.getFamily();
        System.out.println(personJsonTo); //{"name":"riqi","age":26,"family":{"father":"爸爸","mother":"妈妈"}}
        System.out.println(personJsonFrom);//Person [name=riqi, age=26, family=Family [father=爸爸, mother=妈妈]]
        System.out.println(familyJsonFrom);//Family [father=爸爸, mother=妈妈]

        // 借助TypeToken泛型实现对象列表序列化和反序列化
        List<Person> personList = new ArrayList<Person>();
        Type personListType = new TypeToken<List<Person>>() {
        }.getType();
        for (int i = 0; i < 2; i++) {
            Person personTmp = new Person(name, age + i, family); // 年龄做了变化
            personList.add(personTmp);
        }
        String personListJsonTo = gson.toJson(personList, personListType);
        List<Person> personListJsonFrom = gson.fromJson(personListJsonTo, personListType);
        System.out.println(personListJsonTo);//[{"name":"riqi","age":26,"family":{"father":"爸爸","mother":"妈妈"}},{"name":"riqi","age":27,"family":{"father":"爸爸","mother":"妈妈"}}]
        System.out.println(personListJsonFrom);//[Person [name=riqi, age=26, family=Family [father=爸爸, mother=妈妈]], Person [name=riqi, age=27, family=Family [father=爸爸, mother=妈妈]]]
    }
}

对于日常的接口Json数据的序列化和反序列化，以上应该够用了。