Java操作JSON数据(3)--fastjson操作JSON数据

fastjson是阿里巴巴的开源json解析库，它可以解析json格式的字符串，支持将java bean序列化为json字符串，也可以从json字符串反序列化到javabean。本介绍下fastjson的基本使用方法，包括序列化和反序列化；文中所使用到的软件版本：java 1.8.0_191、gson 1.2.62。

1、引入依赖

<dependency>
    <groupid>com.alibaba</groupid>
    <artifactid>fastjson</artifactid>
    <version>1.2.62</version>
</dependency>

2、序列化

    public static string serialize() {
        mybean bean = new mybean();
        bean.sets("测试字符串");
        calendar calendar = calendar.getinstance();
        calendar.add(calendar.hour_of_day, -1);
        bean.setd(calendar.gettime());

        list<mybean> list = new arraylist<mybean>();
        list.add(bean);
        map<string, list<mybean>> map = new hashmap<string, list<mybean>>();
        map.put("data", list);
        
        /*
         * "yyyy-mm-dd hh:mm:ss" 设置日期格式，也可在类属性上使用@jsonfield(format="yyyy-mm-dd hh:mm:ss")注解来设置
         * serializerfeature.writemapnullvalue 输出值为null的字段
         * serializerfeature.writenullstringasempty 字符串如果为null则输出""
         */
        string result = json.tojsonstringwithdateformat(map, "yyyy-mm-dd hh:mm:ss", serializerfeature.writemapnullvalue, serializerfeature.writenullstringasempty); 
        system.out.println(result);
        return result;
    }

3、反序列化

    public static void deserialize() {
        string s = serialize();
        typereference<map<string, list<mybean>>> type = new typereference<map<string, list<mybean>>>(){};
        map<string, list<mybean>> map = json.parseobject(s, type);
        system.out.println(map);
        
        //直接通过api获取相应数据
        jsonobject jsonobject = json.parseobject(s);
        jsonarray jsonarray = jsonobject.getjsonarray("data");
        jsonobject bean = jsonarray.getjsonobject(0);
        system.out.println(bean.getstring("s"));
        //...
    }

4、完整例子

package com.inspur.demo.json;

import java.util.arraylist;
import java.util.calendar;
import java.util.hashmap;
import java.util.list;
import java.util.map;

import com.alibaba.fastjson.json;
import com.alibaba.fastjson.jsonarray;
import com.alibaba.fastjson.jsonobject;
import com.alibaba.fastjson.typereference;
import com.alibaba.fastjson.serializer.serializerfeature;

/**
 * fastjson操作json数据
 */
public class fastjsoncase {
    /**
     * 序列化
     */
    public static string serialize() {
        mybean bean = new mybean();
        bean.sets("测试字符串");
        calendar calendar = calendar.getinstance();
        calendar.add(calendar.hour_of_day, -1);
        bean.setd(calendar.gettime());

        list<mybean> list = new arraylist<mybean>();
        list.add(bean);
        map<string, list<mybean>> map = new hashmap<string, list<mybean>>();
        map.put("data", list);
        
        /*
         * "yyyy-mm-dd hh:mm:ss" 设置日期格式，也可在类属性上使用@jsonfield(format="yyyy-mm-dd hh:mm:ss")注解来设置
         * serializerfeature.writemapnullvalue 输出值为null的字段
         * serializerfeature.writenullstringasempty 字符串如果为null则输出""
         */
        string result = json.tojsonstringwithdateformat(map, "yyyy-mm-dd hh:mm:ss", serializerfeature.writemapnullvalue, serializerfeature.writenullstringasempty); 
        system.out.println(result);
        return result;
    }
    
    /**
     * 反序列化
     */
    public static void deserialize() {
        string s = serialize();
        typereference<map<string, list<mybean>>> type = new typereference<map<string, list<mybean>>>(){};
        map<string, list<mybean>> map = json.parseobject(s, type);
        system.out.println(map);
        
        //直接通过api获取相应数据
        jsonobject jsonobject = json.parseobject(s);
        jsonarray jsonarray = jsonobject.getjsonarray("data");
        jsonobject bean = jsonarray.getjsonobject(0);
        system.out.println(bean.getstring("s"));
        //...
    }
    
    
    public static void main(string[] args) {
        serialize();
        deserialize();
    }

}

package com.inspur.demo.json;

import java.util.arrays;
import java.util.date;

public class mybean {
    private string s = "字符串";
    private string s2;
    private string s3 = "字符串3";
    private int i = 123;
    private integer i2;
    private char c = '到';
    private char[] c2 = new char[]{'a', 'b'};
    private date d = new date();
    private date[] d2 = new date[]{new date(), new date()};
    public string gets() {
        return s;
    }
    public void sets(string s) {
        this.s = s;
    }
    public string gets2() {
        return s2;
    }
    public void sets2(string s2) {
        this.s2 = s2;
    }
    public string gets3() {
        return s3;
    }
    public void sets3(string s3) {
        this.s3 = s3;
    }
    public int geti() {
        return i;
    }
    public void seti(int i) {
        this.i = i;
    }
    public integer geti2() {
        return i2;
    }
    public void seti2(integer i2) {
        this.i2 = i2;
    }
    public char getc() {
        return c;
    }
    public void setc(char c) {
        this.c = c;
    }
    public char[] getc2() {
        return c2;
    }
    public void setc2(char[] c2) {
        this.c2 = c2;
    }
    public date getd() {
        return d;
    }
    public void setd(date d) {
        this.d = d;
    }
    public date[] getd2() {
        return d2;
    }
    public void setd2(date[] d2) {
        this.d2 = d2;
    }
    @override
    public string tostring() {
        return "mybean [s=" + s + ", s2=" + s2 + ", s3=" + s3 + ", i=" + i + ", i2=" + i2 + ", c=" + c + ", c2="
                + arrays.tostring(c2) + ", d=" + d + ", d2=" + arrays.tostring(d2) + "]";
    }
}