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Fastjson中Obejct/Map/JSON/String之间互相转换呢?

陈欣 fastjson 发布时间:2023-08-23 09:22:10 阅读数:7263 1
下文笔者讲述Fastjson中Object,Map,JSON,String之间互相转换的示例分享,如下所示

Fastjson简介

Fastjson是使用Java语言编写的高性能功能完善JSON库
    它采用一种“假定有序快速匹配”的算法
    将JSON Parse的性能提升到极致
    是Java语言中最快的JSON库
    Fastjson接口简单易用
     目前已被广泛使用在
     缓存序列化、协议交互、Web输出、Android客户端等多种应用场景

Fastjson中主要特点

快速FAST(比其它任何基于Java的解析器和生成器更快，包括jackson)
强大(支持普通JDK类包括任意Java Bean Class、Collection、Map、Date或enum)
零依赖(没有依赖其它任何类库除了JDK)
开源
   使用Apache License 2.0协议开源

获得Fastjson

https://github.com/alibaba/fastjson

Fastjson Obejct/Map/JSON/String 互转方法

Fastjson API入口类
com.alibaba.fastjson.JSON
常用的序列化操作都可以在JSON类上的静态方法直接完成 

public static final Object parse(String text); //JSON文本parse为JSONObject或者JSONArray
public static final JSONObject parseObject(String text)； //JSON文本parse成JSONObject
public static final <T> T parseObject(String text, Class<T> clazz); //JSON文本parse为JavaBean
public static final JSONArray parseArray(String text); //JSON文本parse成JSONArray
public static final <T> list<T> parseArray(String text, Class<T> clazz); //JSON文本parse成JavaBean集合
public static final String toJSONString(Object object); //将JavaBean序列化为JSON文本
public static final String toJSONString(Object object, boolean prettyFormat); //将JavaBean序列化为带格式的JSON文本
public static final Object toJSON(Object javaObject); //将JavaBean转换为JSONObject或者JSONArray

Fastjson中常见类库说明

SerializeWriter:
    类似于StringBuffer

JSONArray:
   类似于List<Object>

JSONObject:
   类似于Map<String, Object>

JSON反序列化没有真正数组
      本质类型都是List<Object>

示例代码

package com.java265.json; 

import com.alibaba.fastjson.JSON; 
import com.alibaba.fastjson.serializer.SerializeConfig; 
import com.alibaba.fastjson.serializer.SimpleDateFormatSerializer; 

import java.util.*; 

 
public class Foo { 
	private String vString = "vStringhehhehe"; 
	private char vchar = 'x'; 

	private byte vbyte = 64; 
	private short vshort = 128; 
	private int vint = 65535; 
	private long vlong = 9999999L; 

	private float vfloat = 12.1f; 
	private double vdouble = 22.203d; 

	private boolean vboolean = false; 

//	private Date vdate = new Date(); 
	private Date dddd = new Date(); 
	private Date vDate = new Date(); 
	private Date v_Date = new Date(); 
	private Object vnull = null; 

	private String[] avString = {"aaa", "bbb", "ccc"}; 
	private int[] avint = {1, 2, 3, 4}; 
	private boolean[] avboolean = {true, false, true, true}; 

	private List<String> listString = new ArrayList<String>(); 
	private Map<String, String> map = new HashMap<String, String>(); 

	private Bar bar = new Bar(); 
	private Bar[] avBar = {new Bar(), new Bar()}; 
	private List<Bar> listBar = new ArrayList<Bar>(); 

	{ 
		listString.add("listString1"); 
		listString.add("listString2"); 
		listString.add("listString3"); 

		map.put("x", "s11111x"); 
		map.put("y", "s22222y"); 
		map.put("z", "s33333z"); 

		listBar.add(new Bar()); 
		listBar.add(new Bar()); 
		listBar.add(new Bar()); 
	} 



	public String getvString() { 
		return vString; 
	} 

	public void setvString(String vString) { 
		this.vString = vString; 
	} 

	public char getVchar() { 
		return vchar; 
	} 

	public void setVchar(char vchar) { 
		this.vchar = vchar; 
	} 

	public byte getVbyte() { 
		return vbyte; 
	} 

	public void setVbyte(byte vbyte) { 
		this.vbyte = vbyte; 
	} 

	public short getVshort() { 
		return vshort; 
	} 

	public void setVshort(short vshort) { 
		this.vshort = vshort; 
	} 

	public int getVint() { 
		return vint; 
	} 

	public void setVint(int vint) { 
		this.vint = vint; 
	} 

	public long getVlong() { 
		return vlong; 
	} 

	public void setVlong(long vlong) { 
		this.vlong = vlong; 
	} 

	public float getVfloat() { 
		return vfloat; 
	} 

	public void setVfloat(float vfloat) { 
		this.vfloat = vfloat; 
	} 

	public double getVdouble() { 
		return vdouble; 
	} 

	public void setVdouble(double vdouble) { 
		this.vdouble = vdouble; 
	} 

	public boolean isVboolean() { 
		return vboolean; 
	} 

	public void setVboolean(boolean vboolean) { 
		this.vboolean = vboolean; 
	} 

	public Date getDddd() { 
		return dddd; 
	} 

	public void setDddd(Date dddd) { 
		this.dddd = dddd; 
	} 

	public Date getV_Date() { 
		return v_Date; 
	} 

	public void setV_Date(Date v_Date) { 
		this.v_Date = v_Date; 
	} 

	public Date getvDate() { 
		return vDate; 
	} 

	public void setvDate(Date vDate) { 
		this.vDate = vDate; 
	} 

	public Object getVnull() { 
		return vnull; 
	} 

	public void setVnull(Object vnull) { 
		this.vnull = vnull; 
	} 

	public String[] getAvString() { 
		return avString; 
	} 

	public void setAvString(String[] avString) { 
		this.avString = avString; 
	} 

	public int[] getAvint() { 
		return avint; 
	} 

	public void setAvint(int[] avint) { 
		this.avint = avint; 
	} 

	public boolean[] getAvboolean() { 
		return avboolean; 
	} 

	public void setAvboolean(boolean[] avboolean) { 
		this.avboolean = avboolean; 
	} 

	public List<String> getListString() { 
		return listString; 
	} 

	public void setListString(List<String> listString) { 
		this.listString = listString; 
	} 

	public Map<String, String> getMap() { 
		return map; 
	} 

	public void setMap(Map<String, String> map) { 
		this.map = map; 
	} 

	public Bar getBar() { 
		return bar; 
	} 

	public void setBar(Bar bar) { 
		this.bar = bar; 
	} 

	public Bar[] getAvBar() { 
		return avBar; 
	} 

	public void setAvBar(Bar[] avBar) { 
		this.avBar = avBar; 
	} 

	public List<Bar> getListBar() { 
		return listBar; 
	} 

	public void setListBar(List<Bar> listBar) { 
		this.listBar = listBar; 
	} 
}


package com.java265..json; 

import com.alibaba.fastjson.JSON; 
import com.alibaba.fastjson.serializer.SerializeConfig; 
import com.alibaba.fastjson.serializer.SimpleDateFormatSerializer; 

import java.util.Date; 
import java.util.Random; 

  
public class Bar { 
	public static SerializeConfig mapping = new SerializeConfig(); 
	private String barName; 
	private int barAge; 
	private Date barDate = new Date(); 
	static { 
		mapping.put(Date.class, new SimpleDateFormatSerializer("yyyy-MM-dd")); 
	} 
	{ 
		Random r = new Random(); 
		barName = "sss_"+String.valueOf(r.nextFloat()); 
		barAge = r.nextInt(); 
	} 

	public static void main(String[] args) { 
		Object obj = JSON.toJSON(new Bar()); 
		String x1 = JSON.toJSONString(new Bar(), true); 
		System.out.println(x1); 
		String x2 = JSON.toJSONString(new Bar(), mapping); 
		System.out.println(x2); 
	} 

	public String getBarName() { 
		return barName; 
	} 

	public void setBarName(String barName) { 
		this.barName = barName; 
	} 

	public int getBarAge() { 
		return barAge; 
	} 

	public void setBarAge(int barAge) { 
		this.barAge = barAge; 
	} 

	public Date getBarDate() { 
		return barDate; 
	} 

	public void setBarDate(Date barDate) { 
		this.barDate = barDate; 
	} 

	@Override 
	public String toString() { 
		return "Bar{" + 
				"barName='" + barName + '\'' + 
				", barAge=" + barAge + 
				", barDate=" + barDate + 
				'}'; 
	} 
}


package com.java265.json; 

import com.alibaba.fastjson.JSON; 
import com.alibaba.fastjson.JSONArray; 
import com.alibaba.fastjson.serializer.SerializeConfig; 
import com.alibaba.fastjson.serializer.SimpleDateFormatSerializer; 

import java.util.*; 
 
public class Test { 
	private static SerializeConfig mapping = new SerializeConfig(); static { 
		mapping.put(Date.class, new SimpleDateFormatSerializer("yyyy-MM-dd HH:mm:ss")); 
	} 

	public static void main(String[] args) { 
		Foo f1 = new Foo(); 
		Date date = new Date(); 
		String text = JSON.toJSONString(date, mapping); 
		System.out.println(text); 
		System.out.println(JSON.toJSONString(f1, true)); 
		String x2 =JSON.toJSONString(f1, mapping); 
		System.out.println(x2); 
	} 

	public static void json2List(){ 
		//List -> JSON array 
		List<Bar> barList = new ArrayList<Bar>(); 
		barList.add(new Bar()); 
		barList.add(new Bar()); 
		barList.add(new Bar()); 
		String json= JSON.toJSONString(barList, true); 
		System.out.println(json); 
		//JSON array -> List 
		List<Bar> barList1 = JSON.parseArray(json,Bar.class); 
		for (Bar bar : barList1) { 
			System.out.println(bar.toString()); 
		} 
	} 

	public static void json2Map(){ 
		//Map -> JSON 
		Map<String,Bar> map = new HashMap<String, Bar>(); 
		map.put("a",new Bar()); 
		map.put("b",new Bar()); 
		map.put("c",new Bar()); 
		String json = JSON.toJSONString(map,true); 
		System.out.println(json); 
		//JSON -> Map 
		Map<String,Bar> map1 = (Map<String,Bar>)JSON.parse(json); 
		for (String key : map1.keySet()) { 
			System.out.println(key+":"+map1.get(key)); 
		} 
	} 

	public static void array2JSON(){ 
		String[] arr_String    = {"a","b","c"}; 
		String json_arr_String = JSON.toJSONString(arr_String,true); 
		System.out.println(json_arr_String); 
		JSONArray jsonArray = JSON.parseArray(json_arr_String); 
		for (Object o : jsonArray) { 
			System.out.println(o); 
		} 
		System.out.println(jsonArray); 
	} 
	public static void array2JSON2(){ 
		Bar[] arr_Bar    = {new Bar(),new Bar(),new Bar()}; 
		String json_arr_Bar = JSON.toJSONString(arr_Bar,true); 
		System.out.println(json_arr_Bar); 
		JSONArray jsonArray = JSON.parseArray(json_arr_Bar); 
		for (Object o : jsonArray) { 
			System.out.println(o); 
		} 
		System.out.println(jsonArray); 
	} 

	public static void map2JSON(){ 
		Map map = new HashMap(); 
		map.put("a","aaa"); 
		map.put("b","bbb"); 
		map.put("c","ccc"); 
		String json=JSON.toJSONString(map); 
		System.out.println(json); 
		Map map1 = JSON.parseObject(json); 
		for (Object o : map.entrySet()) { 
			Map.Entry<String,String> entry = (Map.Entry<String,String>)o; 
			System.out.println(entry.getKey()+"--->"+entry.getValue()); 
		} 
	} 
}
 
SerializeConfig
   对序列化过程中一些序列化过程的特殊配置
     这里用作日期格式的定义
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