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。本文介绍下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、fastjson1.2.62。

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.abc.demo.general.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) + "]";
    }
}

package com.abc.demo.general.json;

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;

import java.util.*;

/**
 * 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();
    }

}